CYNGOR CEFN GWLAD CYMRU COUNTRYSIDE COUNCIL FOR WALES

The autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

D.K.Clements & P.Skidmore 2002

CCW CONTRACT SCIENCE REPORT No. 525

CCW CONTRACT SCIENCE REPORT

TITLE: The autecology of the hornet robberfly Asilus crabroniformis in Wales, 1997-1999

REPORT No.: 525

AUTHOR: D.K.Clements & P.Skidmore

PUBLICATION DATE: July 2002

NOMINATED OFFICER: Dr. Mike Howe

RESTRICTION: Nil

DISTRIBUTION:

Core: CCW HEADQUARTERS, LIBRARY ENGLISH NATURE, LIBRARY SCOTTISH NATURAL HERITAGE, LIBRARY BRITISH LIBRARY, DOCUMENT SUPPLY CENTRE NATIONAL LIBRARY OF WALES, ABERYSTWYTH CCW SOUTH AREA (CARDIFF), LIBRARY CCW WEST AREA (ABERYSTWYTH), LIBRARY CCW EAST AREA (LLANDRINDOD WELLS), LIBRARY CCW NORTH-WEST AREA (BANGOR), LIBRARY CCW NORTH-EAST AREA (MOLD), LIBRARY INVERTEBRATE ECOLOGIST, CCW HQ

Others: ENGLISH NATURE, INVERTEBRATE SPECIALIST SCOTTISH NATURAL HERITAGE, INVERTEBRATE SPECIALIST CCW SENIOR CONSERVATION OFFICER, SWANSEA CCW SENIOR CONSERVATION OFFICER, GWENT CCW WARDEN, CRYMLYN BOG GWENT WILDLIFE TRUST A.E.STUBBS

The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

CONTENTS

Summary

Section 1.0 : Introduction

Section 2.0 : Approach & Methods

Section 3.0 : Results

Section 4.0 : Discussion & Conclusions

Section 5.0 : Summary of the Three-Year Study Results

Section 6.0 : References

Acknowledgements

Figure 1 : Map showing the eastern area of Kilvey Hill and western pastures of Crymlyn Bog, indicating main areas of occupation by Asilus crabroniformis in 1999

Figure 2 : Habitats of pasture areas 1 & 2 of Crymlyn Bog

Figure 3 : Habitats of pasture area 5 of Crymlyn Bog

Figure 4 : Habitats of pasture areas 3, 4 and The Mound at Crymlyn Bog

Figure 5 : Recorded movements of five adult Asilus crabroniformis in Crymlyn Bog and the eastern pastures of Kilvey Hill in 1999

Figures 6-10 : Recorded movements of adult of adult Asilus crabroniformis at Brockwell’s Meadows in 1999

Figure 11 : Crymlyn Bog & Kilvey hill area, showing recorded distribution of Asilus crabroniformis in 1999

Figure 12 : Survey of the Usk Valley, Monmouthshire, for Asilus crabroniformis in 1999

Figure 13 : Frame used for captive rearing of Asilus larvae (empty)

Figure 14 : Geotrupes larva in-situ in rearing frame

Figure 15 : Mature larva of Asilus crabroniformis, dorsal view

Figure 16 : Mature larva in side view, showing polygons on sides

Figure 17 : Head capsule of mature larva

Figure 18 : Typical field excavation for larvae of Asilus crabroniformis

Figure 19 : Adult Asilus showing simultaneous capture of a Sarcophaga sp. and Enallagma cyathigerum

Appendix 1 : Survey Results - Day Notes

Appendix 2 : Tabulated Results

Appendix 3 : Survey of Kilvey Hill and the northern parts of Crymlyn Valley, Glamorgan

Appendix 4 : Survey of the Usk Valley, Monmouthshire

The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Summary

This report sets out the results of the final year of a three-year study into the autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales.

The main objectives of this part of the study were to use mark-recapture techniques on adults at Brockwell’s Meadows in Gwent, and Crymlyn Bog/Kilvey Hill in Glamorgan, to investigate adult population sizes and other factors such as longevity and dispersal. Efforts were also continued to find larvae in the field and to study larval behaviour. A subsidiary objective was to investigate the distribution of the species in the valley of the River Usk in Monmouthshire (Gwent).

The study estimated that the total population of adults at Crymlyn Bog varied between 67 to 179 in the period between 27 July - 11 September, peaking between 18-19 August. On the adjacent Kilvey Hill a more limited survey estimated numbers between 155 - 231 in the period 30 July to 11 September. The study at Brockwell’s Meadows estimated adult numbers varying from 51 to 104 in the period 29 July to 1 September, peaking between 31 July - 1 August. The study concluded that the numbers of adults observed by traditional means at any one time typically represent between about 10-20% of the estimated total population, and that the populations at the two sites therefore probably reside in the low hundreds throughout much of the flight period.

Slightly greater numbers of males than females were present, possibly suggesting that females disperse away from emergence sites although it was impossible to detect any clear trends.

Adults were found to be capable of travelling over distances of at least 430m. Typically this appears to be by means of short movements from one patch of dung to another (‘dung-hopping’) although in some instances there was evidence of sustained flight. Long movements of this order could either occur over short time periods (ie several hours) or over longer periods of several days. No clear sexual differences could be found.

Adults longevities of at least 10 days were found to be fairly common, with an average of 15.9 days and a maximum of at least 34 days longevity being observed in the field.

These results are broadly in line with those of two independent studies carried out by researchers in Gwynedd and Oxfordshire.

Rearing experiments and field searches showed that the larvae of Asilus are free-living in the soil, and are almost certainly predatory on the larvae of geotrupine beetles, although this latter point could not be proven definitively. A final instar Asilus larva was encountered in the field, photographed and reared in captivity but showed no inclination to feed over a two month period, before successfully pupating and hatching. The rearing experiments suggest that a one-year life- cycle is possible but may not always be the norm, and that larvae may go without feeding for long periods. It is suggested that the life-cycle period varies according to food availability.

The distributional studies in the valley of the River Usk in Monmouthshire found no evidence of this species in any of the areas examined, even at sites where there were historic records. However, a secondary study of the distribution around Crymlyn Bog and Kilvey Hill in Glamorgan found evidence to suggest that a large area of suitable habitat surrounding Crymlyn Bog and Kilvey Hill is occupied by Asilus.

The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Crynodeb

The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

1.0 INTRODUCTION

1.1 This report has been prepared by David Clements (DKC) and Peter Skidmore (PS) on behalf of the Countryside Council for Wales (CCW).

1.2 This is the final report of a three-year study into the autecology of the hornet robberfly (Asilus crabroniformis) in Wales, carried out during the period 1997-1999. The report sets out the results of survey activities carried out during the summer of 1999, together with a résumé of the findings from the previous two years. Preparation of the final report was delayed by the personal circumstances of the main author.

1.3 Project objectives in the 1999 survey season included the use of mark-recapture techniques to investigate factors such as population dynamics, adult longevity and dispersal. Continuing efforts were also made to find larvae in the field, and to establish their life history and mode of feeding. A subsidiary objective was to carry out surveys to locate new breeding localities for this species in the floodplain of the River Usk in Monmouthshire.

1.4 As in 1998, some additional input was made by Dr Jonty Denton, who has been independently studying this species at Thursley Common in Surrey. The late completion of the present report has also meant that data from two other, independent studies could be incorporated in the discussion. These studies were carried out in Oxfordshire and Gwynedd during 1999-2000 (J. Smith 2000; Lloyd 2001) and also looked at Asilus population dynamics using mark-recapture techniques.

1.5 Full accounts of the previous two years’ work are provided by Clements & Skidmore (1998) and Clements et al (1999), to which reference should also be made.

CCW Contract Science Report No. 525: July 2002 1 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

2.0 APPROACH AND METHODS

2.1 As in previous years, research was concentrated at two sites in South Wales: Crymlyn Bog SSSI near Swansea in Glamorgan, and Brockwell’s Meadows SSSI near Newport in Gwent.

2.2 Crymlyn Bog was primarily studied by PS. The Asilus population at this site is distributed throughout a series of traditionally grazed pastures at the edge of an extensive area of lowland fen, bog and swamp near the mouth of the River Neath. The pastures comprise generally acid dry and marshy grasslands on peaty soils, grazed by ponies, cattle and sheep. The study at this site also extended onto the adjacent Kilvey Hill, which comprises a mixture of grassland, scrub, woodland and revegetated spoil habitats on rising ground adjacent to the SSSI.

2.3 Brockwell’s Meadows was primarily studied by DKC. This site comprises a group of three dry, species-rich neutral (and some calcareous) pasture enclosures on base-rich soils, grazed by cattle, with the Asilus population highly localised on one 2ha slope in the largest field.

2.4 Both of the main sites are described in greater detail in Clements & Skidmore (1998).

2.5 Mark-Recapture Studies

2.5.1 At Crymlyn Bog, individual Asilus adults were captured by hand-net and marked on the wings with an alpha-numeric code, using coloured Staedtler Lumocolor Permanent pens (blue, red, green and black). Adults were captured at random throughout the SSSI (ie no fixed transect or route was followed) over periods of about 4-5 hours. As far as possible, each day spent marking individuals was followed by a repeat visit the next day, when the same procedure was followed. Individual specimens were captured and examined wherever possible, rather than observed on the ground or through binoculars etc. A very detailed tally of each encounter with an Asilus was kept, including the time and location of original capture and also any re-encounter later the same day. This allowed detailed analysis of the movements and habitat preferences of individuals over short periods of time. Mark-recapture studies were carried out on six occasions.

2.5.2 In addition to studies carried out in the Crymlyn Bog SSSI itself, two mark-recapture exercises were also carried out on the adjacent Kilvey Hill. These studies also allowed some investigation of the pattern of dispersal and interchange between adjacent areas.

2.5.3 Draft maps of the broad habitats of the fields surveyed, both in the SSSI and on Kilvey Hill, were prepared for recording purposes (Figs. 1-5). All of the visited fields were numbered, those to the east of Disnam Road (ie within Crymlyn Bog SSSI) by numerals 1 to 8, those west of the road by letters A to I. Fields 8, 9, A, H and I were not included in the mark-recapture exercises.

2.5.4 At Brockwell’s Meadows, individuals were also captured by hand-net and were marked using a coding system. A ‘day-mark’ was made on the thorax using a Pentel Micro- Correct pen to indicate date, whilst individuals were identified by a system of cross- bands made on the wing using a black Staedtler Lumocolor Permanent pen. As at

CCW Contract Science Report No. 525: July 2002 2 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Crymlyn Bog, each day spent marking was followed by a revisit the following day. On each occasion adults were captured at random on the main slope of Banky Field, where the population is concentrated at this site, over periods of about 2-3 hours. Details of both capture and recapture location were recorded, but tracking of individuals over time was not attempted. Mark-recapture studies were carried out on four occasions.

2.5.5 Because of the comparatively low rates of recapture, and the irregularity of the sampling regime, there were limitations on the range and suitability of the analytical tests which could be applied. Analysis was therefore confined to the basic Peterson Method (or Lincoln Index) which assumes that the population is ‘closed’, ie that there are no gains (births or immigrations) or losses (ie deaths or emigrations) occurring between the sample periods. Whilst this is a comparatively crude estimate, it is one which makes relatively few other assumptions and is most suited to low recapture rates (ie <50). Biases resulting from the assumed closed nature of the population is normally kept to a minimum by carrying out the sampling exercises at short intervals (ie 24-48 hours).

2.5.6 The method of choice for ‘open’ populations (ie populations in which gains and losses are taken into account) is the Jolly-Seber Method, but this is likely to give very imprecise estimates in situations where the rate of recapture is <10 (Sutherland 1996), and it was therefore not considered suitable for application to the results obtained by this study.

2.6 Larval Biology

2.6.1 As in previous years, attempts were made to find larvae in the field by means of excavation at sites where adults were previously observed either in-copulo, ovipositing or were present in large numbers. Excavations of approximately 40 x 40cm were made to depths of about 50cm, with soil being carefully hand-searched and/or sieved to extract any larvae (see Fig. 18). Records were made both of any asilid larvae and any potential prey items that were encountered. These studies were carried out at Crymlyn Bog and Brockwell’s Meadows, as well as at Thursley Common in Surrey. Three excavations were carried out at Crymlyn Bog, 6 at Brockwell’s Meadows and three at Thursley Common.

2.6.2 Purpose-built rearing-frames were constructed to contain any larvae encountered (see Figs. 13-14). These comprised vertical frames with two sheets of glass suspended approximately 2cm apart, into which a column of soil containing potential prey items could be introduced. The glass sheets were covered by card to exclude light during normal use, but which could be removed for periodic observation of any larval activity.

2.7 Distributional Studies

2.7.1 Surveys to investigate the presence, or potential presence, of Asilus was carried out in two main areas in 1999: Kilvey Hill and the Crymlyn Valley area surrounding Crymlyn Bog SSSI near Swansea Glamorgan (see Fig. 11), and the valley of the River Usk in Monmouthshire, in Gwent (Fig. 12).

2.7.2 In both cases the areas of search were walked by an experienced surveyor in sunny conditions during the main flight period of the fly. In the case of the Usk Valley, the

CCW Contract Science Report No. 525: July 2002 3 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

surveys were informed by access to the Phase 1 habitat survey prepared by CCW in 1991-92. Survey was targeted towards areas which were mapped as semi-improved or unimproved pasture, as well as exposed river sediments along the course of the river itself.

2.7.3 One strategy which was employed was to look for discarded prey-items lying on the surface of dung. These were retained for subsequent examination under the microscope in order to establish identification and possible causes of death. The point of incision made in the victim by Asilus is seldom visible in the field, but is often distinguishable following microscopic investigation. In many instances in the past the discovery of discarded prey items has been the first indication of the presence of the species in an area.

2.7.4 Prompted by past, isolated records of Asilus from Llanfihangel Gobion in the Usk Valley, a survey was initially commenced in 1997 (Skidmore 1997a) with a view to locating any breeding populations of this species in the Usk Valley. Further sightings in the riverside pastures near Llanover in 1997 appeared to imply a sizeable colony in that area, and in 1997 this was supported by the comments of a local resident who had claimed to have often seen this fly in large numbers up-stream from Llanfihangel Gobion, in the region of the oxbows on the north side of the River Usk.

2.7.5 A survey in 1998 failed to locate any populations in this area (Clements et al 1999), although single individuals were seen in river-side pastures at Clytha, Great Hardwick and at Abergavenny, considerably extending the recorded range of the fly in the Usk Valley and implying perhaps a number of substantial populations in the vicinity from whence the observed individuals may have dispersed.

2.7.6 During 1999 the survey was continued. The survey area was extended from Brecon to Newbridge on Usk, primarily on the left bank of the river and extending up a number of the tributaries (Fig. 12). Informed by the Phase 1 survey maps, the procedure used was to search for cattle or horse grazed pastures and to examine any which appeared to be suitable and which were accessible. From good vantage points, such as that at Cefntilla, it was possible to scan extensive areas of land and to make preliminary assessments concerning the amount of potential Asilus habitat.

CCW Contract Science Report No. 525: July 2002 4 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

3.0 RESULTS

3.1 Mark-Recapture Studies

Crymlyn Bog and Kilvey Hill: 27 July to 11 September

3.1.1 Each day spent in marking flies in the field was followed by a visit a day or two later for recapturing, and this pattern was repeated on four occasions between July 27 to Sept 11. One additional visit was made on 2 Aug, intending to follow this up a day or so later but this proved impossible owing to adverse weather conditions. Similarly, it was not possible to arrange a visit later in September.

3.1.2 The Staedtler Lumicolor Permanent pens used in the field showed considerable colour change and fading with time, although problems arising from this were minimised by the use of a flexible system of coding.

3.1.3 Some 311 individuals were marked at Crymlyn Bog and on the adjacent Kilvey Hill. 44 individuals were subsequently recaptured a day or more after marking:

Sex Total Marked Total Recaptured % of Recapture (% of Total Captured) (% of Total Captured) Male 149 (47.9%) 27 (8.6%) 61% Female 127 (40.8%) 16 (5.1%) 36% Unsexed 35 (11.2%) 1 (0.3%) 2.2% Total 311 (100%) 44 (14.1%)

Table 1: Totals of adult Asilus marked and recaptured at Crymlyn Bog/Kilvey Hill

3.1.4 More males were captured than females and males formed a greater percentage of those recaptured than females, but these differences are not significant when assessed by either Chi-squared or G tests.

3.1.5 In addition, a further 3 individuals (2 male, 1 female) were recaptured on the same day more than an hour after marking, but were not recaptured on a subsequent day.

3.1.6 The day-notes from the Crymlyn Bog mark-recapture studies are set out at Appendix 1, and the tabulated results are given at Appendix 2.

Brockwell’s Meadows: 27 July to 1 September

3.1.7 As with Crymlyn Bog, each visit to the site for the marking of flies was followed wherever possible by a second visit the following day. Unlike Crymlyn Bog, however, there was limited access to areas off-site in the surrounding area, and the investigation was therefore confined to the site itself. For this reason, the Brockwell’s Meadows study concentrated on investigating the absolute population size and the longevity and survivorship of adults.

3.1.8 54 adult Asilus were marked at Brockwell’s Meadows, 13 of which were subsequently re-encountered a day or more after marking.

CCW Contract Science Report No. 525: July 2002 5 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Sex Total Marked Total recapture % of Recaptured (% of Total Captured) (% of Total Captured) Male 29 (53.7%) 8 (14.8%) 61.5% Female 25 (46.2%) 5 (9.2%) 38.4% Unsexed - (0%) - (0%) - (0%) Total 54 (100%) 13 (24%)

Table 2: Totals of adult Asilus marked and recaptured at Brockwell’s Meadows

3.1.9 Slightly more males were captured initially than females and males formed a greater percentage of those recaptured than females, but these differences are not significant when assessed by either Chi-squared or G tests.

3.1.10 The day-notes from the Brockwell’s Meadows mark-recapture studies are set out at Appendix 1, and the tabulated results are given at Appendix 2.

3.2 Estimates of Population Size

3.2.1 Population sizes were estimated using the Peterson Method as set out by Sutherland (1996), using the basic calculation:

N = (n1+1)(n2+1)/(m2+1) –1 N = estimated population size st n1 = number marked and released on 1 occasion nd n2 = total number caught on 2 occasion nd m2 = number of marked individuals caught on 2 occasion

3.2.2 Because of the low rates of recapture it was not generally possible to calculate confidence limits or percentage relative precision (PRP).

Crymlyn Bog

Sample date n1 n2 M2 Population size 27 Jul-30 Jul 14 8 1 67 30 Jul-31 Jul 8 20 4 36 31 Jul-2 Aug 20 11 1 125 18 Aug-19 Aug 15 44 3 179 31 Aug-1 Sept 54 49 19 136 10 Sept-11 Sept 21 15 2 116

Kilvey Hill

Sample date n1 n2 m2 Population size 30 Jul-31 Jul 11 25 1 155 10 Sept-11 Sept 30 14 1 231

CCW Contract Science Report No. 525: July 2002 6 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Brockwell’s Meadows

Sample date n1 n2 m2 Population size 29 Jul-30 Jul 13 14 3 51 30 Jul-1 Aug 14 20 2 104 1 Aug-2 Aug 20 26 5 93 31 Aug-1 Sept 12 11 2 51

Tables 3-6: Population estimates at the study areas in 1999

3.2.3 Sutherland (1996) indicates that situations where the recapture rate is less than 8 are likely to be subject to some bias, and that confidence limits are unlikely to be reliable. The usual method for calculation of confidence limits using this technique is suited to recapture rates of >50 individuals and so is not applicable for these results. However, the recapture rate in the 5th sample at Crymlyn Bog was 19, and it was considered worthwhile attempting to estimate the 95% confidence limits in this one instance using the calculation provided by Sutherland (1996). This gave upper and lower confidence limits of 195 and 108 for the estimated population figure of 136 obtained on that occasion.

3.2.4 These results suggest that that on average the population observed at a site on any one occasion is likely to represent no more than about 10-20% of the actual population present at that time.

200

150

100

50

0 27-30 Jul 30-31 Jul 31 Jul - 2 Aug 18 - 19 Aug 31 Aug - 1 Sep 10 - 11 Sep

Graph 1: Estimated numbers of adult Asilus at Crymlyn Bog in 1999

120 100

80

60 40

20

0 29 - 30 Jul 30 Jul - 1 Aug 1 - 2 Aug 31 Aug - 1 Sep

Graph 2: Estimated numbers of adult Asilus at Brockwell’s Meadows in 1999

3.2.5 The data from Crymlyn Bog indicate that in 1999 there was a steady rise in numbers to a peak between 18-19 August. The slight dip indicated at the end of July is considered unlikely to be significant, but more likely a result of sampling error. The Brockwell’s

CCW Contract Science Report No. 525: July 2002 7 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Meadows data indicate that there was a rise in numbers through July 1999 followed by a fairly gentle fall in numbers through August.

3.3 Dispersal Movements of Adults

Crymlyn Bog and Kilvey Hill

3.3.1 The 47 individuals re-encountered at Crymlyn Bog and Kilvey Hill one hour or more after marking exhibited the following dispersal movements:

Point of Males Females Unsexed Total (%) recapture In same field 16 11 - 27 (57%) In adjacent field 8 3 - 11 (23%) Two fields away 3 1 - 4 (8.5%) Three fields away - 3 - 3 (6.3%) Four fields away 1 - 1 2 (4.2%) Outside the SSSI 1 - - 1 (2.1%)

Table 7: Dispersal from point of capture by adults at Crymlyn Bog/Kilvey Hill

3.3.2 ‘Dispersal distances’ are expressed in terms of movement from one field to the next, rather than as absolute (ie measured) distances

3.3.3 Table 7 above summarises the average dispersal distances observed over the whole study period, but gives no indication of time periods involved. The following table sets out the numbers of individuals observed to have made movements away from the point of first capture, indicating the number of days over which the movements occurred. In addition to individuals that were recaptured more than one hour after marking, the data also include some individuals that were recaptured more than once during the study and individuals which made significant movements (ie into the adjacent field or further) over periods of less than one hour (total 53 observations).

No. of days: <1 1 2 3 6 10 10+ Same field 3 19 - 2 1 - 4 Adjacent field 2 10 1 - - 2 - Two fields away - 1 - - - 1 2 Three fields away - 2 - - - - 1 Four fields away 1 ------Outside the SSSI - - - - - 1 -

Table 8: Dispersal movements by adults observed over time at Crymlyn Bog/Kilvey Hill

3.3.4 It should be noted that the ‘number of days’ scale is not linear because the mark- recapture studies were not carried out at regular intervals. Given the incomplete nature of the data, no attempt has been made to segregate any sexual differences.

3.3.5 Significant dispersal activity was observed in five individuals at Crymlyn Bog (see Fig. 5) which made confirmed movements of 100m or more: these are detailed below:

CCW Contract Science Report No. 525: July 2002 8 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

No. Sex Distance (min) Time between observations 165 Male 430m 10 days 61 Male 400m 5 hrs 43 Male 340m 29 days 145 Female 415m 1 day 241 Female 178m 42 mins 295 ? 100m 1 day

Table 9: Observed dispersal by adults over distances of 100m+ at Crymlyn Bog

Brockwell’s Meadows

3.3.6 Figs. 6-10 indicate the recorded movements of individuals within the main field (‘Banky Field’) at Brockwell’s Meadows. Movements were recorded in 12 individuals at this site, as follows:

No. Sex Distance (min) Time between observations 29/7-4 Male 40m 1 day 29/7-6 Female 25m 1 day 29/7-12 Female 35m 1 day 30/7-2 Male 125m 1 day 30/7-11 Male 45m 1 day 1/8-2 Male 15m 1 day 1/8-7 Male 57m 1 day 1/8-9 Male 90m 1 day 1/8-15 Female 25m 1 day 1/8-16 Male 60m 1 day 31/8-3 Male 12m 1 day 31/8-10 Male 17m 1 day

Table 10: Observed movements of adults at Brockwell’s Meadows

3.3.7 One other individual (Female 29/7-3) was recaptured about 25m away from its original point of capture, but this record is disregarded in the above table since the time elapsed between the two encounters was 34 days, during which time this individual could have ranged both on- and off-site over unknown distances.

3.4 Longevity of Adults

3.4.1 14 adult Asilus were marked and recaptured a significant period (ie 10 days or more) apart. These comprised 13 individuals at Crymlyn Bog and one at Brockwell’s Meadows, and were as shown in Table 11 below. The average (mean) longevity observed in the field was 15.9 days.

CCW Contract Science Report No. 525: July 2002 9 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Specimen No. Sex Minimum observed longevity 43 Male 29 days 48 Female 14 days 64 ? 13 days 66 Male 23 days 90 Female 12 days 95 Female 12 days 105 Male 12 days 147 Female 12 days 165 Male 10 days 168 Female 10 days 182 Male 10 days 29/7-3 Female 34 days

Table 11: Observed minimum longevity of adults

3.5 Larval Biology

3.5.1 The report of the 1998 studies (Clements et al 1999) gave a description of an experiment set up early in September 1998 using a glass aquarium tank in a greenhouse in Swansea. Soil and plants from the centre of Field 3 at Crymlyn Bog SSSI were taken and placed in the tank, taking care to include the clay subsoil beneath the turf layer. Horse dung was placed in the tank together with adult dung beetles (Geotrupes spp) and adult Asilus crabroniformis. Two attempts were made to obtain oviposition, but on both occasions the females lived for a few days only and appeared to be under stress. It was therefore assumed no eggs were laid and that the experiment had failed.

3.5.2 The tank was subsequently left undisturbed until early October 1999, over a year later, when it was carefully emptied. Almost immediately the empty pupal exuvium of a male Asilus, in perfect condition, was found on the soil surface close to old dung-filled burrows of Geotrupes. Two pupal cells of the latter were subsequently unearthed, both of which were empty. About 30cm away from the nearest Geotrupes tunnel, but at a similar depth in the earth (about at the junction of the soil and clay subsoil), a single small larva of Asilus was also found. This was estimated to be about one-third grown, measuring about 13mm when fully extended.

3.5.3 On about the 10 October this larva was placed in one of the vertical rearing frames together with a range of potential prey items, including larvae of Aphodius and Geotrupes dung-beetles, the latter in artificially created ‘dung-galleries’. The Asilus larva was not seen again, and no interaction with prey items was observed. On clearing the frame out in late November 1999 the Asilus larva was found to have died from an unknown cause.

3.5.4 A second Asilus larva was also encountered during the 1999 studies. Dr Jonty Denton, working independently on Thursley Common, a heathland site in Surrey, encountered a fully-grown larva whilst excavating there in mid-October 1999. An excavation had been made in an area containing numerous burrows of both Geotrupes and the related minotaur beetle (Typhaeus typhoeus). The former were encountered at about 30-35cm depth below the surface, whilst the latter ranged from about 20cm to much deeper, 50cm or more. At about 35cm depth, a single Asilus larva was found apparently free- living in the sandy soil. This larva is shown at Figs. 15-17 and measured about 33mm

CCW Contract Science Report No. 525: July 2002 10 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

long when fully extended, with a maximum width of about 5.5mm. The species of the larva was clearly recognisable through its large size, the shape of the head capsule and the conspicuous inflated, polygonal tubercles along the flanks, all of which were described and illustrated in detail from first instar larvae by Clements & Skidmore (1998).

3.5.5 On 21 October 1999, this larva was also introduced into one of the vertical rearing frames with potential prey items. The frame was kept indoors in artificially heated conditions, where it could be readily observed. Over the next few months this larva was highly active, burrowing freely through the loamy, semi-compacted soil in the rearing frame. On one occasion (8 Nov 1999) it was found to have burrowed through a thickness of soil of about 11cm during a period of 2hrs 40mins. However, it showed no interest in any of the prey items available, and was not observed at any time to enter the dung-filled galleries containing the Geotrupes larvae. On 24 December 1999 it was observed to have pupated just below the soil surface near the top of the frame, and an adult female emerged on 7 January 2000. This unseasonably-early pupation and emergence was presumably induced by the artificially high temperature conditions in which the frame had been kept.

3.5.6 Six excavations were made at Brockwell’s Meadows SSSI during the period 30 July to 19 Aug 1999, in areas which were either favoured by adults or where dry cattle dung was concentrated. No Asilus larvae were found, although other species encountered included the larvae of the robberfly Machimus cingulatus (Asilidae) and of the beetles Agrypnus murinus (Elateridae), Aphodius sp (Scarabaeidae), Curculionoidea and Staphylinidae. Geotrupes larvae were found to be extremely scarce. Adults of Agrypnus and several species of weevil were also found. Larvae of the fly Polietes sp (Muscidae) were very common under some dry dung-pats disturbed by the excavations.

3.6 Distributional Studies

3.6.1 Distributional studies carried out as part of this contract covered the wider Kilvey Hill/Crymlyn Valley area surrounding the Crymlyn Bog SSSI, and the lower parts of the valley of the River Usk in Monmouthshire (Gwent). Day-notes from these studies are set out at Appendices 3 and 4.

Kilvey Hill and Crymlyn Valley

3.6.2 The evidence from this study shows that there is continuous and occupied Asilus habitat extending from Crymlyn Bog SSSI to the summit of Kilvey Hill and around its lower flanks above St Thomas. To the north, the fly occurs down to the edges of the residential area north of Llanerch Slant Mine and south of Bon y Maen, eastwards to the northernmost pastures of the Crymlyn Bog SSSI, flanking Disnam Road to its junction with Ty-draw Road - an area of about 2km2 (see Fig. 11). Further north, its occurrence can be confidently predicted as far as the residential areas along Cefn Hengoed Road and Pentre-dwr, and the ungrazed, closed scrub-woodland on the western slopes of Crymlyn Bog north-east of Glan-y-wern Farm adjoining Crymlyn Road, comprising about a further 1km2.

3.6.3 The revegetated tip and adjacent areas between this and Port Tennant offer about a further 1km2 of potentially suitable habitat. The area of Kilvey Hill and Crymlyn Bog

CCW Contract Science Report No. 525: July 2002 11 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

currently occupied by Asilus occupies some 2km2, throughout which the fly could find continuity of suitable habitat. This total range could potentially extend to perhaps twice this area before unsuitable terrain probably limits wider occurrence.

Valley of the River Usk, Monmouthshire

3.6.4 Two survey visits were made in ideal conditions for Asilus, during its flight period. During the days before both visits the fly had been very much in evidence at Crymlyn Bog and Kilvey Hill near Swansea. Many of the sites surveyed along the Usk Valley from Brecon to Newbridge on Usk appeared superficially suitable for the species. No specimens of Asilus were, however, recorded during these surveys even at sites where individuals had been recorded by previous surveys.

3.7 Other Findings

Habitat and Perching Preferences

3.7.1 Habitat preferences were not investigated in a systematic way by this study, but anecdotal observations indicated occupation of habitats including unimproved acid dwarf shrub heath and purple moor-grass (Molinia caerulea) marsh, rough grassland, bramble (Rubus fruticosus agg) and gorse (Ulex sp) thickets, bracken (Pteridium aquilinum) stands, slightly-basic herb-rich pastures with anthills (Lasius flavus), revegetated colliery spoil heaps and improved pastures.

3.7.2 Adults were observed to show preference for rank vegetation such as rough herbage at field edges, patchy heathland and stands of mature bracken, especially where this is regularly trampled by horses. Avoidance of short-grazed areas was observed, as was a general intolerance of wet surfaces.

3.7.3 The perching habits of 547 individuals were recorded at Crymlyn Bog and Kilvey Hill during the 1999 season. These were as follows:

Perch substrate Number of observations Percentage of total Old (dry) horse dung 339 61.9% Old (dry) cow dung 147 26.8% Bare ground 20 3.6% Vegetation (grass stems) 14 2.5% Vegetation (bracken fronds) 5 0.9% Vegetation (bramble leaves) 3 0.5% Stones and rocks 8 1.4% In flight 5 0.9% Other 6 1.0%

Table 12: Observed perching substrates of adults at Crymlyn Bog/Kilvey Hill

3.7.4 Old dry dung is clearly preferred as a perching substrate at this site, particularly that of horses although that of cows is also frequently used. Other substrates are also used, but this would appear to be exceptional.

CCW Contract Science Report No. 525: July 2002 12 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Prey of Adults

3.7.5 The prey of adult Asilus was not investigated systematically during the present study, but the following incidental observations of prey were made:

Coleoptera Dung-beetle, Aphodius spp (Scarabaeidae) Histerid-beetle, Sphaeridium sp (Histeridae) Sexton-beetle, Nicrophorus vespilloides (Silphidae) Rove-beetle, Platydracus stercorarius (Staphylinidae) Rove-beetle, Staphylinus erythropterus (Staphylinidae)

Diptera Crane-fly, Tipula paludosa (Tipulidae) Fly, Sarcophaga sp (Sarcophagidae) Fly, Neomyia sp (Muscidae) Fly, Ernestia sp (Tachinidae)

3.7.6 Of the 547 field observations made at Crymlyn Bog and Kilvey Hill, only 11 (2%) were recorded feeding, the remainder being engaged in other activities, chiefly either perched (‘sunning’) or in flight.

3.7.7 A short note by Clements (1999) reporting the predation of the damselfly Lestes sponsa by Asilus, and also the predation of Asilus by larger Odonata, provoked several responses. Truscott (1999) subsequently reported predation of the damselfly Enallagma cyathigerum by Asilus and provided remarkable photographs showing a female Asilus which had simultaneously captured both an Enallagma and a fleshfly (Sarcophaga sp) (see Fig. 19).

3.7.8 Communications received from Prof. R Lavigne at the University of Adelaide also revealed previous records of Odonata predation by Asilus, involving the dragonfly Sympetrum sanguineum (Gardner 1949; 1950). Sympetrum sanguineum is a substantial insect, typically measuring about 34mm in length (Hammond 1985).

3.7.9 Also brought to light were further notes published in the literature which refer to the predation by Asilus of butterflies (Tunaley 1895), grasshoppers (Killington 1932; Bainbrigge Fletcher 1936; Leclercq 1946), hive bees (Laurence 1950; Bromley 1930), and also the predation of males by females (Hobby 1930).

Egg morphology

3.7.10 The scanning electron microscope (SEM) examination of the egg of Asilus reported in Clements & Skidmore (1998) found the surface of the chorion to be covered with minute spherical bodies and globules, and it was speculated that these might be of artefactual origin, possibly a yeast contaminant. However, Suludere et al (2000) have shown that similar bodies found on the eggs of Machimus rusticus (Meigen) are an integral part of the exochorion.

3.7.11 In 2001, samples of Asilus eggs were sent to Prof. Suludere for examination and comparison with those of M. rusticus. Studies carried out by Prof. Suludere showed that the spherical bodies seen on the surface of Asilus eggs are also structural and not an

CCW Contract Science Report No. 525: July 2002 13 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

artefact. The bodies seen in Asilus are similar to, yet subtly different from, those seen in M. rusticus. In both cases, high magnification examination showed that the bodies seen on the egg surface were in fact a mixture of spherical or sub-spherical projections from the exochorion, together with small dome-shaped, pore-bearing bodies. In cross-section these can be seen to be embedded within the fibrillary matrix of the exochorion, sometimes accommodated at their inner ends within invaginations of the outer surface of the endochorion. The function of this ornamentation is presently unknown.

CCW Contract Science Report No. 525: July 2002 14 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

4.0 DISCUSSION AND CONCLUSIONS

4.1 Population and Biology Studies

Population Size

4.1.1 The estimates of population size obtained by this study suggest that the numbers of adults observed on any one occasion are not a good indication of the total population size. Whilst there was some variation, our results indicated that observed numbers probably comprised no more than about 10-20% of the total population present at the time of observation. This conclusion was borne out by the very low proportion of marked individuals recaptured in samples just a day or so after initial marking. A similar study carried out by J. Smith (2000) on a site in Oxfordshire indicated that the numbers of adults observed represented no more than between 9-15% of the estimated total population, but with a peak of 21.79% in mid to late-August. A study by Lloyd (2001), which used a similar method of calculation to that in the Oxford study, estimated that the observed numbers at Caeau Bwlch SSSI in Gwynedd averaged about 21.6% of the estimated total population.

4.1.2 This suggests that on sites regarded as supporting ‘large populations’, such as Crymlyn Bog and Brockwell’s Meadows, the adult population size is actually likely to number in the low hundreds throughout much of the flight season. Results from the present study indicated maximum estimated adult populations of 179 at Crymlyn Bog (19 Aug), 231 at Kilvey Hill (11 Sept) and 104 at Brockwell’s Meadows (1 Aug). These were rather more than had been anticipated at the outset of the study where, for example, regular counts over many years at Brockwell’s Meadows had given rise to the impression that the total population in a ‘good year’ might comprise perhaps 60-70 individuals at any one time. The population at Brockwell’s Meadows is highly localised in a small area and counting exercises leave the observer with the impression that most of the individuals present on the site have been accounted for. This impression is clearly erroneous. In addition, there are many other sites in Wales where only small numbers of adults have been observed in the past, but these may in fact be indicative of considerably larger populations than has been hitherto recognised (eg Skidmore 1997a).

4.1.3 Populations of adult Asilus are believed to peak in August (Drake 1991). From the data obtained by this study it appears that at Crymlyn Bog in 1999 there was a steady rise to a peak between 18-19 August. An apparent fall in numbers at this site in July is considered unlikely to be significant and is almost certainly an artefact of the sampling methodology, since there were good numbers of adults present at the same time on nearby Kilvey Hill. The Brockwell’s Meadows data indicate that there was a peak in numbers at the end of July 1999 followed by a fairly gentle fall in numbers through August, but it should be noted that there was no sampling carried out between 2-31 August so any peak which may have occurred during this period would have been missed.

4.1.4 The Oxfordshire study indicated a normal, bell-shaped population curve during the period 5 August to 13 September, with an observed population peak in mid to late- August. There was no evidence of cyclical population changes or specific events such as population spikes, such as might be caused by a pronounced second emergence, although the smoothness of the population curve was noticeably interrupted by periods

CCW Contract Science Report No. 525: July 2002 15 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

of adverse weather conditions (J. Smith 2000). The Gwynedd study indicated a population peak in about the third week of August, followed by a smooth levelling-off (Lloyd 2001).

Sex Ratio

4.1.5 Our results indicated slightly greater numbers of males present than females, giving an average ratio of about 1.17:1, male to female, but this does not appear to statistically significant. Data from the Oxford and Gwynedd studies found ratios of about 1.179:1 and 1.25:1 respectively (J. Smith 2000; Lloyd 2001). It is possible that this reflects a genuine difference in the ratio of males to females produced in the population, although it could also have been due to factors such as a greater tendency for females to disperse away from their emergence sites, or some behavioural response which results in males being more-readily captured. A slight prevalence of males in the population would not be unexpected, however, particularly since males may be at slightly greater risk of predation, including by females of their own species.

Dispersal of Adults

4.1.6 Recapture rates at the sites in the present study were significantly higher for males than for females, possibly indicating that males are more sedentary than females although the difference was not statistically significant. Some individuals of both sexes clearly make movements over considerable distances (see below), and given a higher rate of recapture for males it is tempting to conclude that this is especially so in females, which might reasonably be expected to disperse seeking fresh sites for oviposition after mating. There is, however, a need to investigate this in more detail. It would also be valuable to determine whether an individual’s tendency to disperse changes over the course of its adult lifetime and to what degree, if any, this is affected by the act of mating.

4.1.7 The Oxfordshire study also indicated that males were significantly more often re- sighted than females, and it was speculated that this was because males were sedentary whilst females were either dispersing to other oviposition sites or were ‘passing through’ the site en-route to other breeding sites (J. Smith 2000). The latter could be indicative of a metapopulation structure similar to that hypothesised for silver-studded blue butterfly (Thomas & Harrison 1992) and other species.

4.1.8 By contrast, the Gwynedd study appeared to indicate that males dominated dispersion, and it was pointed out that inferences of female dispersion based on the skewed rates of recapture do not take into account the possibility that the difference might have some other cause, such as sex-biased mortality. The evidence for male dispersion in the Gwynedd study was based on actually observed movements, rather than recapture rates, and may therefore be more reliable (Lloyd 2001).

4.1.9 Dispersion patterns may well vary between sites of differing individual characteristics, or between years according to prevailing conditions, weather patterns etc. Females may disperse less if there are ample egg-laying sites available, for example, and vice versa. In years when low numbers of adults emerge or survive, there may be less competition for egg-laying sites. This is clearly an area which requires considerable further investigation.

CCW Contract Science Report No. 525: July 2002 16 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Distances Travelled and Ranges of Adults

4.1.10 No clear trends emerged regarding the tendency to travel significant distances, or the average distances travelled. At Crymlyn Bog the majority of the marked individuals of both sexes appeared to remain close to their original point of capture, at least initially, but a small number of individuals immediately moved considerable distances following capture. Similarly, when analysed over time it appeared that the majority of marked individuals remained in the same locality over periods of 1-2 days after marking, but that some individuals moved considerable distances over shorter periods of time after marking. The majority of marked individuals disappeared from the locality over periods of 5-6 days after marking. This could have been due either to dispersal, or to removal from the population through factors such as mortality, predation etc.

4.1.11 A few individuals appeared to remain sedentary over longer periods of time, ie up to 10 days or more. In these cases, however, it was not possible from the results obtained to rule out the possibility that some seemingly sedentary individuals may have ranged over long distances and then subsequently returned to a site near to their original point of capture. At the much smaller Brockwell’s Meadows site the average movement observed within the site over a 24-hour period was slightly greater for males (average 61.7m) than for females (average 22.8m), but this is unlikely to be significant.

4.1.12 Individuals of both sexes at Crymlyn Bog were found to be capable of movements of 400m+, and in some cases these distances were achieved over comparatively short periods of time (ie, 5hrs or less). A separate study of a number of sites in England by M. Smith (2000) found adults up to 500m away from presumed breeding sites, whilst Lloyd (2001) recorded movements up to a maximum of 760m. The Oxfordshire study recorded movements of up to 138m only (J. Smith 2000).

4.1.13 The Oxfordshire study found that apart from one male which was sedentary, the other individuals studied moved erratically within the site with no tendency to remain in one area. This study also indicated that different individuals may occupy (ie range over) widely differing areas of the available habitat, varying at anything between 0.11 to 3.17ha in extent (J. Smith 2000).

4.1.14 Field observations by the present study indicated that whilst Asilus is clearly capable of strong flight over considerable distances, most movement appeared to be by an incremental process of ‘dung-hopping’, typically involving a low flight of a few metres from one patch of dung to another. It was evident that movement by this means may be achieved over considerable distances. There was no evidence to suggest that they will move through large areas containing no dung, although short bursts of sustained flight may be sufficient to allow passage across small dung-free areas.

4.1.15 One male at Crymlyn Bog (No. 165) was recaptured three times in the first 15 minutes following marking, before it was finally recaptured nearly half a kilometre away some 10 days later. The absolute (ie minimum) distance travelled by this individual was 430m, but if it is assumed that the journey was made by the dung-hopping method, this would have necessitated a more indirect journey of some 550m through the SSSI and across a minor road, followed by an ascent of about 100m up Kilvey Hill. It is considered less likely that this fly took the shorter, more direct route as this would have involved passage over or through an area of dense woodland canopy.

CCW Contract Science Report No. 525: July 2002 17 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

4.1.16 A second male at Crymlyn Bog (No.61) was marked at one end of the SSSI at 10.57am and was recaptured only 5 hours later some 400m away. Superficially it would appear unlikely that this distance was covered in the time observed by the rather slow process of dung-hopping, which would in any case have involved a more circuitous journey of about 550m in total. It may therefore be that one or more periods of direct, sustained flight were involved during this journey.

4.1.17 Interpretation of these observations is not straightforward. However, it seems reasonable to conclude that individuals of both sexes are capable of movement over comparatively long distances (ie 0.5km+) and that this may occur either over short periods of time, or over longer periods. It may be that individuals tend to occupy one location for periods of 1-2 days at a time and then move on to another location, and that in this way they may ultimately disperse long distances during the course of their adult life

4.1.18 The results from Brockwell’s Meadows may indicate that males have a greater tendency to remain for longer in one location than females, but make a greater number of short movements within that location, perhaps as a result of mate-seeking behaviour.

4.1.19 Observations from the present study and those in Oxfordshire and Gwynedd indicate that small linear features such as walls, hedges and even small roads do not appear to pose significant barriers to movement, but that woodland blocks, sheep-grazed pastures or large areas without suitable dung lying on the ground are not readily entered or traversed by adults.

Longevity and Survivorship of Adults

4.1.20 Our results indicate that both males and females are capable of surviving at least 29 days in the field, with one female surviving at least 34 days, and that survivals of 10 days or more are not uncommon. The average longevity was 15.9 days. This is broadly in accordance with the results of the Oxfordshire study, which indicated survivorships (estimated using the Kaplan-Meier function) in excess of three weeks for both sexes. Median survival times of 5-6 days were estimated by the latter study, although this was acknowledged as likely to be an underestimate (J.Smith 2000). The Gwynedd study also recorded longevity of 34 days in a male, with most individuals surviving a minimum of 15 days and a median value of 10 days longevity. No significant sex difference was found (Lloyd 2001).

4.1.21 When observing Asilus adults over a period of days or weeks in a given site, they may be thought to be the same individuals, based on the assumption that such a robust and aggressive insect would tend to be long-lived and territorial. As noted above, such observations may lead to the belief that the population is small and that one is seeing the same individuals repeatedly over long periods of time. Clearly, Asilus adults are capable of comparatively long survivals in the field, but this study shows that assumptions concerning their lack of mobility and the small size of the population are unlikely to be correct.

4.1.22 It was observed during the present study that as the season progressed a larger proportion of the individuals captured showed severe fraying of the wing-margins, and that in some cases flight capability was seriously impaired (see Appendix 1: Crymlyn Bog day notes). One male at Crymlyn Bog (No.138) was found to be quite incapable of

CCW Contract Science Report No. 525: July 2002 18 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

flight, having the apical half of the left wing missing completely; the most that this individual could manage was an ungainly wing-assisted hop of about 15cm. Observations indicated that older individuals were generally recognisable by wing- fraying and a diminution of the contrast in the abdominal coloration, the yellow colour often appearing whitish and faded. The intensity of the dark marginal wing-flecks also appears to decrease with age.

4.1.23 Field observations also indicated considerable disparity in the vigour of individuals. Whilst most immediately took off in fast straight flight after marking, some individuals displayed frailty and trauma after only gentle handling, lying motionless on their side for a moment or two before recovering and flying off. One small male failed to recover from the experience, whilst a female in seemingly pristine condition (No.164) also appeared to be in a very fragile state. The latter remained on the dung when the net was placed over her and had to be picked off by hand. After marking she remained perched in the same place on the dung, before finally climbing onto an overhanging bramble leaf as the evening shadows moved onto the dung some hours later.

Territoriality

4.1.24 Field observations and the results of the mark-recapture study have shown no clear evidence of territorial behaviour in this species. Two individuals of the same sex can frequently be seen on the same patch of dung within clear view of each other and seldom interact, although past observations have shown that matings may be initiated on dung patches, especially when one of the individuals takes off (Clements & Skidmore 1998). Field observations and marking of individuals have shown repeatedly that when an adult Asilus is seen on a particular dung patch on two or more occasions, for example after a lapse of several minutes, or when one individual flies off and then apparently returns shortly afterwards, it cannot be assumed that this is the same individual. Marking indicates that just as often they are in fact different individuals.

4.1.25 This concurs with previous observations made during this study, which indicated only weak and temporary associations between individuals and particular perches, and with the Oxfordshire study which found no evidence of territoriality (J. Smith 2000). Painter (1997) claimed to have detected territorial use of perches by males at Crymlyn Bog, but the ‘aggressive grappling’ described as occurring when individuals land on a perch occupied by an incumbent male may just as likely have been attempts at copulation. Observations of territorial behaviour were also claimed by Pinchen et al (1998) using marked adults, but their studies took place over short periods of time and gave inconclusive results.

4.1.26 The Oxfordshire study found no statistical evidence to support the holding of territories by adult Asilus despite intensive study. However, it was suggested that adult Asilus could be regarded as defenders of ‘personal space’, possibly as a defence against cannibalism, a well-documented and frequently observed phenomenon (J. Smith 2000).

Habitat Preferences

4.1.27 The 1999 studies confirmed the occurrence of Asilus adults in a very wide range of habitats in Wales. At the Crymlyn Bog site alone these include unimproved heathland, purple moor-grass mires, rough grassland, bramble, gorse and bracken thickets, herb- rich pastures, improved pastures and revegetated colliery spoil. Studies elsewhere

CCW Contract Science Report No. 525: July 2002 19 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

(summarised by Clements & Skidmore 1998) have indicated use of a wide range of grassland and heathland habitats, broadleaved and conifer woodland clearings and sea cliffs. A study of sites in England found that most fell into three categories, either heathland, downland or agricultural pasturelands, but that there was considerable heterogeneity within these categories and the species did not appear to be restricted to any particular habitat type (M. Smith 2000). This study also noted the presence of a population on a secondary, artificially-created meadow site less than ten years old.

4.1.28 The principle habitat components suggested by Skidmore (1997b) continue to apply in the majority of cases known to us. These comprise light, well-drained soils and abundant ungulate (or, in some English localities, rabbit) dung supporting rich coprophilous faunas which include geotrupine beetles. Observations from the 1999 season suggest that the presence of, or proximity to, tall vegetation and/or scrub may also be important, possibly related to the roosting requirements of the adult. Close- cropped vegetation generally appears to be avoided, which may explain the absence (in Wales at least) of Asilus from sites which are primarily or exclusively grazed by sheep.

Perching Preferences

4.1.29 At Crymlyn Bog it was clear that, where choice was available, old horse-dung was the preferred perching substrate in the area studied, with cow-dung in second place. It had been noted on previous occasions, and was frequently observed during this study, that where cows and horses share pasturage the flies show a marked preference for horse- dung although at least some marked individuals were seen to visit both. In addition to any chemical differences, cow and horse dung differ in their physical characteristics. Horse-dung is of much firmer consistency from the outset, and Asilus adults may be seen on very fresh horse-dung (an incidental observation by DKC at Thursley Common recorded Asilus perching on horse dung within a few minutes of its deposition). Many adults were seen at Crymlyn Bog on horse-dung which was only a few hours old, still very dark in colour and covered in sphaerocerid flies, sometimes also accompanied by Polietes domitor. By contrast, adults appear almost never to perch on cow dung which does not have a firm crust.

4.1.30 At other sites (eg Brockwell’s Meadows) where cattle are the only grazing animal, the great majority of adults perch on dry cow dung (Clements & Skidmore 1998). In some parts of England adults perch on rabbit latrines (eg Surrey, and perhaps Dorset: see Pinchen et al 1998; Skidmore 1999) but this phenomenon does not seem to have been observed in Wales. Very few Asilus adults have been observed perching on substrates other than horse and cow dung (Skidmore 1997a; Clements & Skidmore 1998), and records elsewhere of their alighting on wet cow dung are considered likely either to be exceptional or erroneous.

4.1.31 Observations to date indicate that Asilus does not utilise sheep dung, at least in Wales, and this was further supported by independent surveys carried out in Devon (Skidmore 1999). However, the study carried out by M. Smith (2000) which looked at 40 recent Asilus sites in England found the species occurring on a small percentage of sites where sheep are the only grazing stock, or where there are no grazing stock at all. However, these are mostly downland sites where it is probable that rabbits also occur, and in at least one case cattle are also known to occur in adjacent pastures nearby.

CCW Contract Science Report No. 525: July 2002 20 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

4.1.32 Capture locations for adults in the Gwynedd studies were primarily on cow dung (72%), with the remainder either on grass (21%) or ‘other’ substrates (5.5%). No significant sex differences were found (Lloyd 2001).

Prey of Adults

4.1.33 Clements & Skidmore (1998) summarised the wide range of prey items tackled by this species. Additional literature references and observations during the 1999 season confirmed the predation of Odonata by Asilus, including the robust species Sympetrum sanguineum (Müller), and brought to light an incidence of multiple prey-taking.

4.1.34 The predation of Odonata by asilids (including Asilus) probably occurs with more frequency than might be supposed. Clements (1999) suggested that records of Odonata predation were rare in the literature, but additional records have subsequently emerged. As long ago as 1903, McLachlan reported the predation of Orthetrum dragonflies by an Asilus species in ‘Persia’ (McLachlan 1903). Truscott (1999) reported the predation of the damselfly Ischnura elegans (Vander Linden) by Asilus, and documented the simultaneous capture of both this species and a fleshfly (Sarcophaga sp) by a single Asilus adult (see Fig. 19). Stoks & Bruyn (1996) have reported intensive predation of the damselflies Lestes sponsa (Hansemman) and Enallagma cyathigerum (Charpentier) by the asilid Eutolmus rufibarbis (Meigen) in Belgium, a species which is of similar size to Asilus. The damselflies were all caught in flight and were mostly males. These authors suggest that in some situations predation by asilids may be a significant mortality factor for damselflies.

Other Observations

4.1.35 Other observations collected during the 1999 season included the finding that the fly will remain active in very light rain, but quickly ‘goes to ground’ with the onset of a significant downpour. The adult flies also appear to be very intolerant of wet surfaces. Only in one of the 547 observations made at Crymlyn Bog was an Asilus perched in such a way as to be in contact with water. This was of an adult which was resting momentarily on the rim of a hoof-print on a muddy path with the apex of its abdomen touching the water. None was seen resting on wet foliage. This further supports the contention that wet dung is avoided for perching.

4.1.36 Observation on Kilvey Hill, notably in Fields D and M, has shown that Asilus adults are quite capable of negotiating very steep slopes, providing they are traversed by tracks which are strewn with horse or cow dung. Progression upslope is usually by means of ‘dung-hopping’.

4.1.37 It is often stated that adult Asilus do not become active until mid to late-morning (eg Titcombe 1982). Whilst they are rarely seen early in the morning, the 1999 season nevertheless showed that adults can be active by 10.00am. It may be that their activity is related to evaporation of any dewfall and the drying of vegetation, given that the fly appears to be intolerant of wet surfaces.

CCW Contract Science Report No. 525: July 2002 21 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

4.2 Larval Biology

4.2.1 The key observation that Asilus larvae are predatory on geotrupine beetle larvae remains elusive. However, the 1999 studies have shown beyond all reasonable doubt that the larvae are free-living in the soil, and have lent strong support to the supposition that such predation occurs.

4.2.2 In the experiment set up in an aquarium tank in 1998 (Clements et al 1999), it is assumed that the adult Geotrupes which were originally placed in the tank must have created dung-filled galleries, oviposited and produced larvae which lived long enough to form pupal cells. However, as there was no sign of adult Geotrupes having emerged from these cells and it must also be assumed that these either died or were killed before reaching maturity.

4.2.3 It is not possible to be certain that there were no Asilus larvae present amongst the mass of roots in the turf when it was placed in the tank, but given the amount of time and effort spent to date trying unsuccessfully to find larvae of this species in the field (Clements & Skidmore 1998, Clements et al 1999) this appears unlikely in the extreme. It is far more likely that the two Asilus larvae present in the tank a year later resulted from eggs laid by one or other of the females placed in the tank in September 1998.

4.2.4 The circumstances found when the tank was emptied a year later were strongly suggestive of predation of the geotrupine larvae by one or both of the growing Asilus larvae. It appears likely one larva reached maturity within the course of a year by preying upon the developing Geotrupes progeny, whilst the other was unable to locate sufficient prey to complete its development in the space of a single year. This is not unlikely, since studies elsewhere have shown that in some predatory Muscidae, for instance, some larvae reach maturity much more quickly than others of the same age depending on the availability of prey (Skidmore 1985). The growth of those unable to find sufficient prey may be delayed by several months. It is quite possible that the same phenomenon occurs in Asilus.

4.2.5 The rearing studies also showed that mature larvae do not seemingly need to take prey during the final weeks or months prior to pupation and emergence. This phenomenon has also been observed elsewhere, for example in the related brachyceran fly Xylophagus ater (Diptera, Xylophagidae) (Clements 1998). This, coupled with the two larval size classes found in the tank, and the slow growth observed elsewhere in a first instar larva (Clements & Skidmore 1998), may point to a physiological adaptation to survive through significant periods of enforced starvation with a reduced rate of growth.

4.2.6 It is considered virtually impossible that mature or semi-mature Asilus larvae were introduced to the tank accidentally when the experiment was set up. Even if very small Asilus larvae had been present in the turf placed in the tank, predation of the geotrupines could only have occurred some time after the experiment commenced, as there were certainly no larval galleries or pupal cells present at the outset. If, as is assumed here, the larvae in fact developed from eggs laid by the captive adults, the results suggest that the life-cycle of Asilus may be completed in a single year, but may be dependant on finding sufficient prey during that time. In circumstances where prey are scarce, it may be that the Asilus larva is capable of surviving the enforced starvation and that the life- cycle may be extended into a second year.

CCW Contract Science Report No. 525: July 2002 22 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

4.3 Distributional Studies

4.3.1 Investigations into the distribution of Asilus in the wider Kilvey Hill/Crymlyn Valley area around Crymlyn Bog SSSI have shown that the species is much more widespread than was originally suspected; that there is interchange between populations in Crymlyn Bog and Kilvey Hill; and that Kilvey Hill itself probably supports a significant population of this species.

4.3.2 A significant part of the land occupied by Asilus on Kilvey Hill and the Crymlyn Bog pastures is technically derelict land, insofar as it was once the site of numerous coal drift-mines, such as that at Llanerch Slant, and associated spoil heaps. In several places the fly now occurs on old colliery spoil heaps, notably in the Crymlyn Bog SSSI itself and at Llanerch Slant, but these workings date from over a century ago and are now almost wholly revegetated, with many supporting diverse semi-natural plant communities and effectively constituting high quality unimproved secondary pasture.

4.3.3 According to the recollections of local residents, extending back some 70 years in some cases, the fields on Kilvey Hill down to the edges of Crymlyn Bog have always been grazed by horses and cattle. None of those spoken to recalled any active drift mines in this area. However, local residents recall that the western slopes of the hill, overlooking the Swansea valley, were once so blighted by pollution from the industrial complexes of the valley floor that nothing grew on the western end of Kilvey Hill, and there were only a few scattered areas of very poor ungrazed grassland. Moreover, during the last war that end of the hill received heavy incendiary bombing and burned for several months. This situation changed in the period after the war, however, following the demise of the industries of the lower Swansea Valley and an environmental recovery programme and afforestation scheme which was carried out from the summit of Kilvey Hill westwards into the lower Swansea Valley.

4.3.4 During the time that the Swansea valley industries were fully active, and the western slopes of Kilvey Hill were intensely polluted, the eastern slopes of Kilvey Hill apparently presented a complete contrast. Here there was a truly rural landscape with scattered farms, hedges, woods and verdant cattle and horse-grazed pastures sloping down to the unbroken mass of Crymlyn Bog itself. Presumably during this period Asilus was largely restricted to these eastern slopes of the hill and the edges of Crymlyn Bog, but it must have subsequently successfully colonised many areas of derelict land on the western slopes as the pollution sources were removed and they gradually became revegetated.

4.3.5 This, together with the evidence gathered by this study regarding high mobility and wide range of habitat preferences, suggests that Asilus is quite capable of colonising from one site to another provided they are not isolated by large tracts of unsuitable land (‘unsuitable’ may, in this instance, simply mean not containing dung of the right type, and/or in sufficient quantity, to allow movement or dispersal by means of ‘dung- hopping’, which appears to be the normal mode of movement). If the normal life-cycle is assumed to be one year, as indicated by the present studies, it may be that the withdrawal of grazing from a pasture during the flight period of Asilus (ie from late July to September), even for just a few seasons, could result in localised extinction at that site. In the past this may not have been significant, for there would have been a greater likelihood of suitable (ie dung-strewn) habitat linking the site to other populations in the area, so that at such time as it came back into a suitable, grazed condition,

CCW Contract Science Report No. 525: July 2002 23 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

recolonisation by Asilus adults dispersing from other sites would have occurred quite readily.

4.3.6 One of the main reasons for the demise of Asilus in Britain and across much of Europe may therefore arise from changes in land use from pasture to arable farming, and the trend away from cattle farming to sheep, and the resulting loss, fragmentation and isolation of suitable breeding habitats. Asilus is likely to be most vulnerable to localised extinction where it is restricted to small isolated populations. Once lost as a result of even quite temporary changes in land use which make a given site unsuitable, recolonisation may not now be possible at a later date because of the lack of suitable contiguous habitats linking the site with other populations.

4.3.7 Conversion of former pastures to arable crop production has occurred over vast areas of western Europe. Much of north-eastern Europe, and many parts of France, are probably now more-or-less devoid of Asilus owing to the widespread disappearance of pastoral farming and its replacement by arable farming. A similar situation now exists within much of the former English range of Asilus (which originally extended south of a line running approximately from the Bristol Channel to the Wash – see Drake 1991) and particularly to the east, where arable farming is now far more widespread than cattle pasture. This is less the case in western and northern England, and throughout much of Wales, but the problem in these areas may have been compounded by the widespread replacement of horses and cattle by sheep. As stated above, there is considerable evidence that sheep dung is not acceptable to Asilus. Asilus populations are also likely to have suffered further from the BSE outbreak in the late 1980’s-1990’s which led many farmers to replace cattle with sheep, and possibly also from the rising use of Ivermectin treatments from the early 1980’s (see Skidmore 1997b). The Foot & Mouth epidemic of 2001 is also likely to have had an impact on this species.

4.3.8 The predominance of sheep, rather than cattle or horses, may also be a factor affecting populations of Asilus in the valley of the River Usk. No specimens of Asilus were recorded during surveys in the Usk Valley in 1999, even at sites where individuals had been recorded by previous surveys. The 1999 work has shown that Asilus has considerable powers of dispersal providing that it is able to proceed by ‘dung-hopping’ along a continuous succession of horse or cattle grazed areas. In recent years this continuity may have been broken in the Usk Valley by an increase in arable farming, especially of maize in the lower reaches below Abergavenny, or through the replacement of cattle by sheep.

4.3.9 Although no specimens of Asilus were seen in any of the many suitable localities along the Usk in 1999, it cannot be assumed that the fly no longer occurs along the valley, however. A number of potential sites on the southern and/or western banks of the river remain to be investigated, and a visit to Pen-y-Bryn in Merioneth in 1997 (one of the strongholds of the species in Wales) made in suitable weather ended without any Asilus having been seen (Skidmore 1997a). This provides a salutary reminder that it is possible to visit a site which is known to support a good population, without a single specimen being seen.

CCW Contract Science Report No. 525: July 2002 24 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

5.0 SUMMARY OF THE THREE-YEAR STUDY RESULTS

5.1 This report marks the culmination of a three-year study into the biology of Asilus crabroniformis in Wales. The results arising from each year of the study are set out in detail in the reports by Clements & Skidmore (1998), Clements et al (1999) and the present report. The following comprises a brief résumé of the main findings in each of the three years of the study:

Year 1

5.2 The main objectives of the Year 1 study was to elucidate the ovipositional behaviour, larval biology and habitat requirements of Asilus. This was carried out through detailed field observations in the summer of 1997 which included the videotaping of behaviour in the field, characterisation of habitat and niche requirements and the captive rearing of larvae, coupled with a detailed review of the literature. The study also included the novel description of the first instar larva and SEM examination of both this and the egg of Asilus crabroniformis.

5.3 It was concluded that oviposition occurs throughout the period August to September and tends to occur in warm weather, with most observations occurring in the afternoon. Oviposition in surface crevices of dung was most usual, although oviposition around dung, into or onto the soil, or low down on grass stems was also confirmed, as was oviposition directly into the soil away from dung, although these were less usual. The dung chosen for oviposition was usually dry, and in the case of cow dung typically very dry-crusted and carton-like, and may or may not support an abundant dung fauna. Oviposition onto dung with almost no associated dung-fauna occurred in some cases. Wet, very fresh and moist dung was almost universally avoided by ovipositing females. Dung chosen for oviposition was normally at least 2-3 weeks old, often appreciably more, usually standing in full sunlight and often with an elevated temperature relative to the ambient air temperature. The study found that the dung of cattle, horses and rabbits may be used for oviposition but that sheep dung is avoided. Eggs were laid singly, usually well-separated from each other and well-concealed. Hatchling larvae were found to require a substrate to burrow into in order to fully exit from the egg shell.

5.4 The precise mode of larval nutrition could not be confirmed, but evidence from the Year 1 study pointed to a predatory mode. An association with scarabaeid beetle larvae was indicated. Scarabaeids, especially the dung beetles of the genera Geotrupes, Aphodius and Typhaeus were a common and probably universal feature of habitats occupied by ovipositing females. Development in the first instar larva was found to be slow, suggesting a developmental period over two years or more. First instar larvae were reared in quite small quantities of damp dung matter, and were believed to be feeding on nematode worms or the first instar larva of other insects. No larvae were found in the field during the Year 1 study, despite searches at several sites.

5.5. The study found that a wide range of habitat types are used by Asilus populations in Britain, including calcareous, acid and neutral grasslands, semi-improved and improved species-poor grasslands, wet heathland, dry heathland, coastal grasslands and clearings in scrub and woodland. Some populations have even successfully recolonised disturbed ground such as ploughed pasture and revegetated colliery waste. Common features of the habitats chosen were usually light, often free-draining soils and the presence of dung of

CCW Contract Science Report No. 525: July 2002 25 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

varying ages, usually supporting a rich coprophilous fauna. The dung of ungulates is probably not essential, although it probably does need to be that of a herbivore. The catholicity of habitats used suggested that the lack of suitable habitat is unlikely to be a factor in the species’ recent decline in Britain.

5.6 The study concluded that topography, aspect and the presence of certain suites of physical features in the habitat may all be critical in determining its suitability for Asilus. Necessary physical features were considered to include the presence of suitable roosting habitat (eg woodland, scrub, hedgerows, tall herbaceous vegetation such as bracken, Pteridium aqulinum) nearby and the presence of abundant perches. Thermoregulation was found to be an important factor for this species, with a distinct preference for hot, sunlit conditions with plentiful opportunities for 'sunning'. Adult activity was found to require air temperatures of at least 16oC. Observations of roosting behaviour included documentation of a ‘head-down’ roosting posture.

Year 2

5.7 Study in Year 2 was hampered by poor weather conditions and low population numbers. The main objectives were continued investigation into the biology of the larva, coupled with investigations into the distribution of the species in an area of Wales where it was suspected to occur, namely in the valley of the River Usk in Monmouthshire.

5.8 Investigations into the larval biology were carried out mainly through searches in the field, with the excavation and sieving of soils from pits dug on sites where large populations of Asilus occur. At least 40 pits were dug at Brockwell’s Meadows and Crymlyn Bog in Wales and another two sites in England, but no larvae were found. However, in-vivo rearing was attempted using a large aquarium containing soil, dung and potential larval prey items.

Year 3

5.9 The main objectives of the Year 3 study were to use mark-recapture techniques on adults at Brockwell’s Meadows in Gwent, and Crymlyn Bog/Kilvey Hill in Glamorgan, to investigate adult population sizes and other factors such as longevity and dispersal. Efforts were also continued to find larvae in the field and to study larval behaviour. A subsidiary objective was to investigate the distribution of the species in the valley of the River Usk in Monmouthshire (Gwent).

5.10 The study estimated that the total population of adults at Crymlyn Bog varied between 67 to 179 in the period between 27 July - 11 September, peaking between 18-19 August. On the adjacent Kilvey Hill a more limited survey estimated numbers between 155 - 231 in the period 30 July to 11 September. The study at Brockwell’s Meadows estimated adult numbers varying from 51 to 104 in the period 29 July to 1 September, peaking between 31 July - 1 August. The study concluded that the numbers of adults observed by traditional means at any one time typically represent between about 10- 20% of the estimated total population, and that the populations at the two sites therefore probably reside in the low hundreds throughout much of the flight period. Slightly greater numbers of males than females were present, possibly suggesting that females disperse away from emergence sites although it was impossible to detect any clear trends.

CCW Contract Science Report No. 525: July 2002 26 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

5.11 Adults were found to be capable of travelling over distances of at least 430m. Typically this appears to be by means of short movements from one patch of dung to another (‘dung-hopping’) although in some instances there was evidence of sustained flight. Long movements of this order could either occur over short time periods (ie several hours) or over longer periods of several days. No clear sexual differences could be found. Adults longevities of at least 10 days were found to be fairly common in the field, with an average of 15.9 days and a maximum of at least 34 days longevity being recorded.

5.12 The results of the mark-recapture experiments were found to be broadly in line with those of two other independent studies carried out by researchers in Gwynedd and Oxfordshire.

5.13 Rearing experiments and field searches showed that the larvae of Asilus are free-living in the soil, and are almost certainly predatory on the larvae of geotrupine beetles, although this latter point could not be proven definitively. A final instar Asilus larva was encountered in the field, photographed and reared in captivity but showed no inclination to feed over a two month period, before successfully pupating and hatching. The rearing experiments suggest that a one-year life-cycle is possible but may not always be the norm, and that larvae may go without feeding for long periods. It is suggested that the life-cycle period varies according to food availability.

5.14 The distributional studies in the valley of the River Usk in Monmouthshire found no evidence of this species in any the areas examined, even at sites where there were recent records. However, a secondary study of the distribution around Crymlyn Bog and Kilvey Hill in Glamorgan found evidence to suggest that a large area of suitable habitat surrounding Crymlyn Bog and Kilvey Hill is occupied by Asilus.

CCW Contract Science Report No. 525: July 2002 27 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

6.0 REFERENCES

Bainbrigge Fletcher, T (1936) Asilus crabroniformis at Stroud in 1935. Entomologist’s Record & Journal of Variation 48: 10.

Bromley, S W (1930) Bee-killing robberflies. Journal of the New York Entomological Society 38: 159-176.

Clements, D K (1998) Rearing Xylophagus ater Meigen (Diptera, Xylophagidae) larvae under observable conditions. Dipterists Digest (NS) 5: 1-5.

Clements, D K (1999) The hornet robberfly Asilus crabroniformis L. (Diptera, Asilidae): interactions with Odonata. Journal of the British Dragonfly Society 15: 18- 19.

Clements, D K & Skidmore, P (1998) The autecology of the hornet robberfly Asilus crabroniformis L. in Wales, 1997. CCW Contract Science Report 263. Countryside Council for Wales, Bangor.

Clements, D K & Skidmore, P & Denton, J (1999) The autecology of the hornet robberfly Asilus crabroniformis L. in Wales, 1998. CCW Contract Science Report 344. Countryside Council for Wales, Bangor.

Drake, C M (1991) Provisional atlas of the larger Brachycera (Diptera) of Britain and Ireland. Institute of Terrestrial Ecology, Monks Wood.

Gardner, A E (1949) [Exhibit: Sympetrum sanguineum (Odonata: Libellulidae) as prey of Asilus crabroniformis]. Proceedings & Transactions of the South London Entomological & Natural History Society 1949: 1 (also reported in Eagles, T R, 1949 [Society Reports] Entomologist’s Monthly Magazine 85: xi).

Gardner, A E (1950) The life history of Sympetrum sanguineum Müller (Odonata). Entomologist’s Gazette 1: 21-23.

Hammond, C O (1985) The Dragonflies of Great Britain and Ireland (2nd Edition, revised R Merritt). Harley Books, Colchester.

Hobby, B M (1930) A female Asilus crabroniformis L. devouring its male. Proceedings of the Entomological Society of London 5: 110-111 (also reported in Neave, S A, 1931 [Society Reports]. The Entomologist 64: 95-96).

Killington, F J (1932) Asilus crabroniformis Linn. (Dipt., Asilidae) with acridian prey (Orthop.). Journal of the Entomological Society of the South of England 1: 110.

Laurence, B R (1950) Predators and prey. The Bedfordshire Naturalist 4: 27-30.

Leclercq, M (1946) Some predacious flies and their prey. Entomologist’s Monthly Magazine 82: 177.

CCW Contract Science Report No. 525: July 2002 28 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Lloyd, D (2001) Dispersal abilities and population structure of the adult hornet robberfly Asilus crabroniformis at Caeau Bwlch SSSI. CCW Contract Science Report No. 458. Countryside Council for Wales, Bangor.

McLachlan, R (1903) [Exhibit: Orthetrum dragonfly preyed upon by an asilid]. Proceedings of the Entomological Society of London 1903: ix.

Painter, D (1997) Monitoring the hornet robberfly Asilus crabroniformis at Crymlyn Bog NNR 1997. Countryside Council for Wales (internal report).

Pinchen, B, Denton, J & Bird D (1998) The hornet robberfly Asilus crabroniformis Linnaeus: adult behaviour at selected sites in Dorset, Hampshire and Surrey in 1997. EN Science Report 274. English Nature, Peterborough.

Skidmore, P (1985) The Biology of the Muscidae of the World. Series Entomologica, W Junk.

Skidmore, P (1997a) The status of the hornet robberfly Asilus crabroniformis in South Wales. CCW Contract Science Report 212. Countryside Council for Wales, Bangor.

Skidmore, P (1997b) Survey of the insect fauna of the dung of ungulates on Exmoor. Exmoor National Park Contract Report (unpublished).

Skidmore, P (1999) The status of the hornet robberfly Asilus crabroniformis in certain National Trust properties in Devon. National Trust Invertebrate Survey Reports. National Trust, Cirencester.

Smith, J (2000) Population dynamics of the adult Asilus crabroniformis. BSc thesis, University of Reading (supervisor: G Holloway).

Smith, M (2000) The hornet robberfly Asilus crabroniformis: land use and livestock grazing regimes at sites in England. English Nature Research Reports 387: 30pp.

Stoks, R & Bruyn, L de (1996) Intensive feeding of the robberfly Eutolmus rufibarbis (Diptera, Asilidae) on the damselflies Enallagma cyathigerum and Lestes sponsa (Odonata). Bulletin (et Annales) de la Societe Royale d’Entomologie de Belgique 132: 427-431.

Suludere, Z, Candan, S, Kalender, Y & Hasbenli, A (2000) Ultrastructure of the chorion of Machimus rusticus (Meigen, 1820) (Diptera, Asilidae). Journal of the Entomological Research Society 2; 63-71.

Sutherland, W (1996) Ecological Census Techniques: a handbook. Cambridge University Press.

Thomas, C D & Harrison, S (1992) Spatial dynamics of a patchily-distributed butterfly species. Journal of Animal Ecology 61: 437-446.

Titcombe, C (1982) Bandits at Banky Field. Wildlife Magazine 24: 246-247.

CCW Contract Science Report No. 525: July 2002 29 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Truscott, L (1999) The hornet robberfly Asilus crabroniformis L. (Diptera, Asilidae): Odonata as prey. Journal of the British Dragonfly Society 15: 50.

Tunaley, H (1895) [Exhibit: Asilus crabroniformis with Lycaena icarus Rott. (Lepidoptera) as prey]. Proceedings of the South London Entomological & Natural History Society 1895: 62 (also reported in Turner, H J, 1896 [Society Reports] The Entomologist 29: 69).

CCW Contract Science Report No. 525: July 2002 30 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

ACKNOWLEDGEMENTS

The authors wish to express their gratitude to the following for help and assistance during the present study: Dr. Jonty Denton, Dr. Martin Drake (formerly of English Nature), Fritz Geller-Grimm, Prof. Rob Lavigne (University of Adelaide), David Painter (Crymlyn Bog SSSI Warden), Dr. Wolfgang Schneider (Darmstadt Museum), Dr. Robby Stoks (University of Antwerp), Alan Stubbs, Prof. Zekiye Suludere (Gazi University), Dr. Richard Tofts, and Jon Winder (formerly of Gwent Wildlife Trust). Ken Clements very kindly made up the larval rearing frames, and Leon Truscott provided the photograph used at Figure 19.

This project was carried out under contract to the Countryside Council for Wales (CCW Contract FC 73-01-215), supervised by Dr. Mike Howe to whom we are grateful for advice and forbearance.

CCW Contract Science Report No. 525: July 2002 31 Fig. 1: Map showing the eastern area of Kilvey Hill and western pastures of Crymlyn Bog, indicating main areas of occupation by Asilus crabroniformis in 1999 Fig. 2: Habitats of pasture areas 1 & 2 at Crymlyn Bog

Fig. 3: Habitats of pasture area 5 at Crymlyn Bog Fig. 4: Habitats of pasture areas 3, 4 and The Mound at Crymlyn Bog Fig. 5: Recorded movements of five adult Asilus crabroniformis in Crymlyn Bog and the eastern pastures of Kilvey Hill in 1999 Figs 6-10: Recorded movements of adult Asilus crabroniformis at Brockwell’s Meadows in 1999

Upper Rodge Wood

29/7-6

29/7-4

29/7-12 Break of Slope

Base of slope

50m approx

Hedge Fig. 6: 29-30 July 1999 Hedge

Male Female

Upper Rodge Wood

30/7-2

30/7-11 Break of Slope

Base of slope

50m approx

Hedge Fig. 7: 30 July – 1 Aug 1999 Hedge

Male Female

Upper Rodge Wood

1/8-16 1/8-15 1/8-9 1/8-2 1/8-7

Break of Slope

Base of slope

50m approx

Hedge Fig. 8: 1 Aug – 2 Aug 1999 Hedge

Male Female Pair in cop

Upper Rodge Wood

29/7-3 Break of Slope

Base of slope

50m approx

Hedge Fig. 9: 29 July – 31 Aug 1999 Hedge

Male Female

Upper Rodge Wood

31/8-10

31/8-3 Break of Slope

Base of slope

50m approx

Hedge Fig. 10: 31 Aug – 1 Sept 1999 Hedge

Male Female

Fig. 11: Crymlyn Bog & Kilvey Hill area, showing recorded distribution of Asilus crabroniformis in 1999 Fig. 12: Survey of the Usk Valley, Monmouthshire, for Asilus crabroniformis in 1999 Fig. 13: Frame used for captive rearing of Asilus larvae (empty)

Fig. 14: Geotrupes larva in-situ in rearing frame Fig. 15 (above): Mature larva of Asilus crabroniformis, dorsal view Scale is mm

Fig. 16 (top right): Mature larva in side view, showing polygons on sides of segments

Fig. 17 (bottom right): Head capsule of mature larva Fig. 18: Typical field excavation for larvae of Asilus crabroniformis; peg marks position of cow pat where oviposition had been observed

Fig. 19: Adult Asilus showing simultaneous capture of Sarcophaga and Enallagma cyathigerum (L. Truscott) The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

APPENDIX 1: SURVEY RESULTS – DAY NOTES

1) Crymlyn Bog SSSI (P Skidmore)

In the SSSI, eight ‘fields’ of varying sizes were recognised for recording purposes in this study, namely seven adjoining Dinam Road, numbered from 1 to 7 northwards, and ‘the Mound’ - an old revegetated colliery spoil-heap to the east of Field 4 and separated from it by a narrow belt of marsh along the margins of the Cwm stream (Maps 1, 3). Fields 4 to 7 are separated from one another by fences, the remainder by lines of trees and shrubs. Field 5 (Fig. 4) contains patches of gorse-dominated thicket and has two main pasture areas, here referred to as Clearing 1 (adjoining the southern fence separating it from Field 4) and Clearing 2 (bordering the fence separating Fields 5 and 6) .

The following abbreviations are used:

m : male f : female ocd : old cow-dung ohd : old horse-dung Fld : field Mnd : The Mound

In some instances the sex of individuals was not noted; these are indicated by a question mark. Other observations which did not form part of the mark-recapture exercise are shown in italics.

27 July 1999

Warm sunny day with a little cirrus cloud only. Assisted on this occasion by the Assistant Warden, Jo Davies. Using a black butterfly net on this day.

Field 1 Entered 11.42; horse-dung contained sphaerocerids and masses of larvae of Polietes domitor (Muscidae); no Asilus seen.

Field 2 Entered 12.15; no Asilus seen.

Field 3 Entered 12.45; 12.50 [1] 1f on ohd in midfield marked with 1 green line on right wing (ie.G1R) 12.55 [2] 1m on ohd midfield, marked with 2 green lines on right wing (ie.2GlR) 13.41 [3] 1m on ohd midfield, marked 3GlR 13.49 [4] 1m on ohd north-east part (caught by Jo), marked 4GlR 13.56 [5] 1f on ohd north-east part (Jo), marked 5GlR 14.11 [6] 1f on ohd midfield, marked 6GlR 14.29 [2] 1m (Recapture) on ohd midfield- 2GlR (marked at 12.55 in same area) 12.45 - 14.30 five seen on ohd midfield, at least two individuals of which may have included one or more of above. two seen on ohd in southern part one seen on ohd by Jo in north-east in heather area one seen on ohd amongst rushes east of telegraph pole (tp)

Field 4 Entered 14.40; 14.40 [7] 1m on ohd north-west corner between gate, road and valley, marked 1 green line on left wing (1GlL) 14.42 [8,9] pair in cop on ohd close to previous, 1f marked 2GlL; 1m marked 3GlL 14.48 [10,11] pair in cop on ohd just inside FC north fence, by road; 1f marked 4GlL; 1m marked 5GlL 14.53 [12] 1f on ohd amid heather in valley, just south of path, marked 6GlL 15.15 [13] 1m on ohd midslope near southern tree edge, marked 7GlL one seen on ohd near previous

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Field 5 Entered 15.20; 15.30 one seen resting on crow feather by path in first clearing (Clearing 1), by gorse. In following 10 minutes Jo and I missed one (?same individual) another three times in same area of Clearing 1, twice on old cow dung (ocd)

Field 6 15.44 to 15.52; none seen

Field 7 15.53 to 16.12. none seen

Mound Entered 16.16; 16.17 [14] 1m on ohd by gate 8GlL 1 seen on same pat, perhaps same individual

Summary for 27 July 14 specimens (8m, 6f) marked – Fld. 1(-); 2(-); 3(3:3); 4(4:3); 5(-); 6(-); 7(-); Md.(1m). 1 recapture (1m) in Fld. 3(1).

14 additional sightings- Fld. 1(-); 2(-); 3(9); 4(l); 5(4); 6(-); 7(-); Md.(1). Maximum individuals: 28; minimum: 19. Substrates- ohd- 23; ocd- 2; crow feather on grass-1. Two pairs in cop. (in Field 4).

The majority of specimens appeared very alert and difficult to catch. This may have been an effect of “youthfulness” but may also have resulted from use of a black (ie, visible) net. The SSSI Warden David Painter reported that the first Asilus of the year was seen on 25 July by Jo, and that none were seen on his last circuit walk on 21 July. All of the specimens handled on the 27 July were pristine; none had any fraying of the wings. The single recapture was of a specimen marked only 34 minutes earlier and caught in the same area, namely midfield in Field 3

30 July 1999

Bright still day, about 30OC or more. Using black net again. Slight southerly breeze developed by midday, making conditions fresher.

Field 1 Entered 11.11; 11.16 - 11.35 six seen on ohd - may perhaps all have been same individual, though subsequent work suggested this was probably not the case.

Field 2 Entered 11.38; 11.39 [15] 1m on ohd southern end of anthill section, marked 1 black line on right wing- 1NlR 11.45 [2] 1f (Recapture) on same ohd as one seen at 11.42- 2GlR (marked in field 3 midfield on 27 July). 11.42 one seen on path through bracken/bramble 11:56 one seen on ohd north-west corner, on edge of bracken bed 12:00 one f seen on ohd on path through bracken

Field 3 Entered 12.03; 12.08 [16] 1m on ohd in south east part by tree edge, marked 2NlR 12.25 one f seen on ohd by road-fence

Field 4 Entered 12.32; 12.48 [17] 1m on ohd by Field Centre north fence junction with roadside fence, 3NlR 12.51 [18] 1m on same pat, marked 4NlR 13.00 [19] 1f on ohd by path in valley section, marked 5NlR 13.10 [17] 1m (Recapture) on grass between heather clumps-3NlR (marked at 12.48, 88 paces to north-east.) 13.35 [19,20] pair in cop on ohd by path in valley near northern corner of heather area- 1m marked with 1 black line on left wing (1NlL); 1f (Recapture) marked 5NlR (marked in same area at 13.00) 13.4 1m on ohd on verge between wooden bridge and gate into field 5. A very small male which was perhaps teneral or sickly. I marked it with 2NlL but it did not survive the ordeal so I retained it. The code was re-used at 14.12 for a specimen later captured on the mound. 14.25 [21] 1m on ohd by path on valley slope, marked 9GlL (using green pen as black pen mislaid) 12.59 one seen on ohd amongst bramble by tree edge west of path in valley in north-west corner

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

13.00 one f on ohd by path in mid section of valley [at 13.00] 13.04 one seen on ohd amongst heather a yard or so from the one under 13.00 above 13.23 one f on ohd by tree edge in southeast, disturbed by passing Meadow Brown butterfly (Maniola jurtina). 13.32 one seen on ohd on northern edge by wooden bridge 14.23 one seen on ohd just inside gate into Field 5 where the small male was caught at 13.41

Field 5 Entered 13.46; no Asilus seen

Field 6 Entered 13.50; no Asilus seen

Field 7 From 13.58 to 14.01; no Asilus seen

Mound Entered 14.12; 14.12 [22] 1m on ohd by gate, marked 2NlL (the one marked thus at 13.41 did not survive) 14.12 one seen on ohd by gate on same pat as that marked at 14.13 by Jo was perhaps the same individual

Summary for 30 July Marked 9 (8m1f)- Fld. 1(-); 2(1m); 3(1m); 4(5:1); 5(-); 6(-); 7(-); Md.(1m). 3 recaptures (2m 1f)- Fld. 2(1m); 4(1:1). 17 additional sightings- Fld. 1(6); 2(3); 3(1); 4(6); 5(-); 6(-); 7(-); Md.(1). Maximum individuals: 27; minimum: 11. Substrate- ohd 26; grass 1; bare earth 1. One pair in cop (in field 4).

Of the nine specimens marked, one male marked in Field 4 with code 2NlL did not survive the trauma of capture, so actually only eight are listed on Table 1 (Appendix XX). Another individual caught on the Mound was subsequently given the same code 2NlL. Of the three recaptured, one (3NlR) had travelled from the vicinity of the Field Centre gate in Field 4 to the lower valley area of the same field, a distance of about 70m, in 22 minutes. The other in Field 4 had stayed in the same area for 35 minutes. Individual 2GlR had moved some 250m southwards from the middle of Field 3 to the southern end of Field 2 in 3 days.

31 July 1999

A warm bright day

Field 1 Entered 11.50; 11.54 one seen on ohd midfield 11.55 one seen ohd on northern edge amongst bracken

Field 2 Entered 12.02; 12.04 [23] 1m on ohd amongst bracken by western edge of junction of open and anthill sections, marked with one black x on right wing (ie.1NXR) 12.14 [23] 1m (Recapture) on ohd in middle of anthill sector- 1NXR (had moved about 15m in 10 minutes). 12.15 [24,25] pair on ohd amidst bracken. They did not appear to have been perched on dung but on vegetation - flew off a few metres in tandem then settled again on trampled bracken where I caught them; 1f marked 2NXR, 1m marked 3NXR 12.11 one seen on ohd on southern edge of anthill section 12.44 one seen on ohd in extreme north-west corner by path through bracken

Field 3 Entered 12.34; 12.36 [25] 1f on ohd by entrance by roadside fence in extreme south-west corner, where path enters from Field 2, marked 1NXL 12.49 [26] 1m on same pat as previous, marked 3NXL 12.54 [27] 1m on ohd further north along western field edge marked 4NXL 12.46 one seen on dung patch next to one where 1NXL and 3NXL marked 13.00 one seen on ohd midfield 13.03 one seen on ohd by trees on southern edge

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Field 4 Entered 13.26; 13.27 [19] 1f (Second recapture) on ohd to left of Field Centre gate entrance to field- 5NlR (marked in Field 4 valley on 30 July) 13.34 [28] 1m on ohd on valley crest, 4m left of path, marked with 3 black blobs on left wing and 2 on right (ie.3N.L2N.R) 13.39.1 [21] 1m (Recapture) on ohd by path in valley- 9GlL (marked in same area on 30 July) 13.43 [29,30] pair in cop on bare ground on path; f marked with 4 black X on each wing (ie.4NXR4XL), m marked with 2 black X on each wing and apical blob on right wing (2NX.R2XL) 14.05 [31] 1m on ohd mid-slope east of FC marked with a green X on right wing (ie.1GXR) 14.17 [32] 1? On ohd by northern edge by trees, just east of path, marked 2GXR 14.21 [308] 1? On ohd by tree edge west of path, just opposite arrow-post on path, marked 3GlR 14.26 [33] 1m on same pat as one marked 2GXR at 14.17 above, marked 2NXR2XL 14.32 [309] 1m on ohd by path on slope into valley, marked with 2 green blobs on right wing (ie.2G.R) 15.00 [22] 1m (Second recapture) on same pat as where 3GXR marked- 9GlL (marked in same area on 30 July) (caught at 15.00) 15.02 [30] 1m (Recapture) on ohd near gate- 2NXR2NXL (marked at 14.26 above, in valley area of same field) 15.04 [309] 1m (Recapture) on ohd by path slope into valley- 2G.R (marked an hour earlier in same area.) 13.30 one seen on ohd by gate entrance 13.36 two seen, one on stone just left of path and the second flew up from grass nearby 13.50 one seen on ohd among heather by trees on northern edge 13.55 one seen on ohd 3m from previous 13.56 one seen on bare ground on path by arrow- post 13.56 one seen on ohd near path 4m away from previous 14.08 - 14.15 four seen on ohd on heathery slopes west of Field Centre 15.05 one seen on ohd by gate from Field Centre

Mound Entered 14.31; 14.32 [34] 1m on ohd by gate, marked 2G.R (In error, the code had already been used above) 14.36 [20] 1m (Recapture) on rather fresh horse-dung covered in sphaerocerids- 1NlL (marked on 30 July in valley area of Field 4) 14.38 [35] 1m on ohd in channel, marked with 1 green blob on right wing (ie.1G.R) 14.41 [21] 1m (Recapture) on grass in channel- 2NlL (marked on 30 July on mound)

Field 5 Entered 14.57; 14.57 one seen again on ocd in Clearing 1 by path where Jo and I missed one four times on 30 July

Summary for 31 July 15 marked (10m 3f 2?) Fld. 1(-); 2(2:1); 3(2:1); 4(4:1; 2?); 5(-); 6(-); 7(-); Md.(2:). 8 recaptures (7:1)- Fld. 2(1m); 4(4:1); Md.(2m) [including 1 second recapture in field 4]. 20 additional sightings- Fld. 1(2); 2(2); 3(3); 4 (12); 5(1); 6(- ); 7(-); Md.(-). Maximum individuals: 38; minimum: 18. Substrate- ohd- 32; ocd- 1; ground 2; stone 1. Two pairs in cop, in Fields 2 and 4.

Of those recaptured, the male in Field 2 had travelled 15m in 10 minutes. Of those recaptured in Field 4, all except 2GlR had remained in the north-western part of the field (valley area and vicinity of Field Centre gate), two for at least 24 hours. Male 2GlR in contrast had travelled from the channel on the Mound to the path slope into the valley in Field 4 in 32 minutes. Of the two recaptured on the Mound, one (2NlL) had been there at least 24 hours, whilst the other (1NlL) had travelled during that time from the valley area of Field 4, a distance of about 100m.

Thus, out of the seven individuals recaptured in Field 4 and on the Mound, two (ie.28%) had travelled the 100m between the Mound and Field 4. Had they taken the direct route, it would have entailed traversing some 40m of wet marsh, but a longer and much more circuitous ‘dry-land’ route would have been via the path into Field 5 then down the track towards the marsh and through the fence on the north side of the Mound- perhaps some 150m. Certainly the flies do follow the first part of this route in passing between Fields 4 and 5, but none have been seen by PS on the track to the marsh, despite the presence of horse dung. Whilst the longer route may possibly have been taken by 1NlL, this seems unlikely for 2G.R purely from a consideration of the time taken. In any event there is clearly easy and regular passage for Asilus adults between these two areas.

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Of the seven individuals recaptured on 31 July (omitting the second recapture of 9GlL in Field 4), two had travelled at least some 100m over partially inhospitable terrain (inundated marshland), or much more improbably had taken a longer journey along the paths as mentioned above. Three had remained in the same area of Field 4 for at least 24 hours, whilst the remaining two were recaptured at most 15m from the places they were marked, 10 and 36 minutes earlier.

2 August 1999

Warm and close, 50% cloudy after slight rain earlier in day

Field 1 Entered 15.01; Marking with black blob followed by numeral on right wing 14.08 [36] 1f on ohd amongst bracken, marked N.1R 15.06 [37] 1f on ohd amongst bracken 2m from previous, in north-west corner by horse-track through boundary bushes, marked N.22R (first 2 did not show properly) 15.09 [38] 1f on ohd 30cm away from previous, marked N.3R 15.13 [39] 1m on grass path by ohd where one seen at 15.03, marked N.4R 15.16 [23] 1m (Second recapture) on ohd on bracken edge just east of main entrance to field- 1NXR (marked on 31 July in bracken area of Field 2) 15.03 one seen on grass on bracken edge just north of pylon. A dead Ernestia sp. (Tachinidae) was found on ohd some inches away.

Field 2 Entered 15.20; 15.23 [40] 1m on next ohd to that where one seen at 15.22, marked N.5R 15.34 [41] 1f on ohd on edge of bracken in north-west corner, by path, marked N.6R 15.39 [15] 1m (Recapture) on ohd on horse track through rank bracken by roadside fence- 1NlR (marked on 30 July in same area) 15.22 one seen on ohd on bracken edge at open area/anthill sectors 15.26 one seen on ohd very close to previous 15.30 one seen on ohd on eastern edge of anthill section 15.34 two seen on ohd in bracken area 15.35 one seen on ohd on edge of bracken in north-west corner 15.42 one seen on ohd amongst trampled bracken by roadside fence

Field 3 Entered 15.48; 15.49 [42] 1m on ohd just by entrance to field, by roadside fence, marked N.7R 15.55 one seen on ohd midfield

Field 4 Entered 16.07; 16.10 [11] 1m (Recapture) on ohd in valley, on west of path- 5GlL (marked on 27 July in same area) 16.14 pair on grass on path beside heather- [19] female (Second recapture)- 5NlR (marked on 30 July in same area of Field 4); [43]male marked N.8R 16.25 [44] 1m on ohd in front of Field Centre, near fence, marked N.9R 16.28 [45] 1m (very large) on ohd by Field Centre gate marked N.10R 16.08 one seen on ohd by gate 16.20 one seen on ohd among heather near path (near arrow- post) 16.42 - 16.43 two seen on ohd by path in valley

Mound Entered 16.34; none seen

Summary for 2 August 10 marked (6:4)- Fld. 1(1:3); 2(1:1); 3(1m); 4(3m); 5(-); 6(-); 7(-); Md.(-). 4 recaptures (3:1) – Fld. 1(1m); 2(1m); 4(1:1), including 2 second recaptures in Flds. 1 and 4. 13 additional sightings- Fld. 1(1); 2(7); 3(1); 4(4); 5(-); 6(-); 7(-); Md.(-). Maximum individuals: 25; minimum: 13. Substrate- ohd-23; grass- 2. One pair in cop.

Of the four individuals recaptured, the one in Field 2 (1NlR) and two in Field 4 (1GlL and 5NlR) were recaptured in the areas of the respective fields in which they were marked, 1NlR and 5NlR 3 days earlier on 30 July, 1GlL 6 days earlier

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999 on 27 July. The male 1NXR had moved some 150m south from the bracken area of Field 2, where it was marked on 31 July, into similar terrain in Field 1.

Thus, out of four individuals (all males) which were recaptured, three appear to have been extremely sedentary, the fourth to have travelled only a short distance through very similar terrain.

11 August 1999

This was not a part of the mark-recapture exercise but just a fleeting visit during the late afternoon of the day of the total eclipse. The weather was dry and warm with intermittent bright periods. 11 Asilus were seen as follows- 8 on ocd in Field 6 (including a pair in cop), 2 on the path in Field 5, 1 on ohd in Field 4. None appeared to have been marked and most appeared to be females.

Summary for 11 August 11 seen: Fld. 4(1); 5(2); 6(8). Substrate- ohd- 1; ocd- 8; bare soil- 2

18 August 1999

A sunny day after two days of heavy rain. Wind northerly, temperature about 18oC, heavy cumulonimbus about and fresh.

Field 1 Entered 14.31; no Asilus

Field 2 Entered 14.36; 14.41 one seen on ohd amidst bracken

Field 3 Entered 14.49; 14.51 [46] 1m (very large) on grass in north-west corner, marked with red line on right wing (R1R) 15.01 [47] 1m very small) on ohd midfield, marked 2RlR 15.07 [48] 1f (large) south of midfield, just west of path, flying very ponderously as it was carrying a large m Sarcophaga sp. as prey, marked 3RlR 15.09 [49] 1m on ohd about 2m south of last, marked 4RlR. This exuded blob of white fluid from rear end. 15.14 [50] 1f on ohd near pylon flew off when approached and landed some metres away on dead twig on the ground, where it was caught, marked 5RlR. (Also exuded white blob of fluid from rear) 14.56 one seen on ohd midfield

Field 4 Entered 15.22; 15.24 [51] 1f on ohd by gate, marked 6RlR 15.37 [52] 1f on stone in valley near path, marked 7RlR 15.36 one seen on grass in valley by path

Field 5 Entered 15.34; 16.10 [53] 1f on ocd in anthill section of Clearing 2, just before gate into Field 6, marked 8RlR 16.15 [54] 1f near previous, on ocd marked with 8 red lines on right wing and 1 on left (ie 8RlR1L) 16.21 [55] 1f on ocd by marsh-edge brambles at foot of Clearing 2, marked 9RlR1L 16.28 [56] 1f (very small) on ocd by marsh-edge, marked 8RlR3RlL 15.56 one seen on ocd in Clearing 1 16.02 one seen down-slope of previous, on ocd which was still damp after rain 16.20 one seen on ocd in anthill section near marsh edge had Neomyia sp. (Muscidae) as prey- which it dropped on taking to flight 16.25 one seen on ocd on marsh edge near previous 17.03 pair on grass on path just inside gate into Field 6 17.06 one on grass by muddy path flew a few metres and landed on edge of rut in wet mud, its tail touching the water surface, then flew off again into brambles by path.

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Field 6 Entered 16.32; 16.35 [57] 1f (small) on ocd by roadside fence, midway along just south of small mound, marked with the numeral 12 in red on right wing (ie. R12R) 16.47 [58,59] pair in cop on ocd by gate onto fen; f marked with 2 red circles on right wing (2ROR), m marked with 3 (3ROR) 16.53 one seen on ocd right on edge of rushes on marsh edge

Mound Entered 17.09; 17.10 [60] 1f on grass in channel flew ponderously onto gorse where it was caught; it was carrying a dead Nicrophorus vespilloides (Silphidae); individual was marked with 5 red blobs on right wing (ie.5R.R)

Summary for 18 August 15 marked (4m11f)- Fld. 1(-); 2(-); 3(3:2); 4(2f); 5(4f); 6(1:2); 7(-); Md.(1f). No recaptures. 11 additional sightings- Fld. 1(-); 2(1); 3(1); 4(1); 5(7); 6(1); 7(-); Md.(-). Maximum individuals: 26; minimum: 16. Substrate- ohd- 4; ocd- 12; stone- 1; bracken- 1; grass- 5; in flight-1. Three taken with prey- Sarcophaga, Neomyia and Nicrophorus vespilloides. Two pairs in cop.

Interestingly there were no recaptures on this visit, not even of specimens marked on the day.

19 August 1999

Bright sunny morning, with slight northerly wind, c.21oC, but more in shelter from wind.

Field 1 Entered 10.54; 10.57 [61] 1m on grass near ohd at bottom of slope, marked with 1 blue circle on right wing (ie. 1BOR) 11.07 [62] 1f on bracken flew a few metres and landed again on bracken, marked with 1 blue, red centred circle on right wing- 1BO(R.)R 10.54 one seen on path at field entrance

Field 2 Entered field at 11.32; 11.59 [50] 1f (Recapture) on ohd on bracken edge flew off then back onto bracken then onto grass by same dung patch 5RlR (marked on 18 August near pylon in Field 3). 11.58 [63] 1m on ohd in north-west corner amongst bracken and bramble, marked with 3 red-centred blue circles on right wing (ie 3BO(R.)R) 12.04 [48] 1f (Recapture) on ohd amongst bracken- 3RlR (marked on 18 August near southern edge of Field 3). 12.05 [48] 1f (Second recapture) on ohd on path through bracken- 3RlR (just released, marked at 12.06) 12.09 [64] 1? On ohd a few metres further north along same track, marked with 4 blue, red-centred circles on right wing (ie.4BO(R.)R) 12.16 [63] 1f (Recapture) close to previous, on ohd- 3BO(R.)R (just marked at 11.58 in north-west corner of Field 2 - see above. 18 minutes after marking, observed that the blue colour was barely discernible as it had assumed a very strong reddish violet lustre, merging with the red central blotches) 11.34 one on short turf near Inula bed flew into this as I approached 11.40 one landed on net whilst I was dealing with the one netted at 11.39

Field 3 Entered 12.21; 12.23 [65] 1? landed on bramble leaf by roadside fence near field entrance from Field 2, marked with four open blue circles on right wing (ie 4BOR) 12.33 [66] 1m (very large) on ohd south of midfield, marked 6BOR 12.22 one seen on ohd by roadside fence near field entrance from Field 2 (a metre south of previous) 12.53 one on ohd midfield by Field Centre 13.09 [67] 1f on ohd in corner of Field Centre enclosure in corner of roadside fence and north fence, to left of gate into Field 4, marked with 6 blue, red-centred circles on right wing (ie. 6BO.R)

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

16.59 [67] 1f (Second recapture) on fairly fresh ohd beside drive into Field Centre- 6 blue, red-centred circles on right wing (ie.6BO(R.)R) (the above specimen, marked at 13.09).

Field 4 entered 13.0; commenced observations 14.20; 13.13 [67] 1f (Recapture) on ohd 5m north-north-west of gate- 6BOR.R (marked at 13.09 in Field Centre enclosure- see above) 13.20 [68] 1f on bramble leaf in valley, not close to dung, marked 2 open blue circles on left wing (ie.2BOL) 13.25 [69] 1f on ohd on scrub edge west of arrow-post on path, flew onto ground between brambles, marked 4BOL 13.29 [70] 1m on very dry fragment of ohd on short grazed area between heather downslope of path in valley, marked 3BOL2OR 13.33 [71] 1f on ohd on marsh edge at bottom of valley, marked 4BOL3OR 13.35 [72] 1? on valley-side track on north edge of slope east of Field Centre, flew down track towards wood pile and landed on ohd, marked with 4 blue circles on each wing (ie. 4BOL4OR) 13.45 [73,74] pair in cop. on ohd mid-slope near southern edge by scrub, female marked with 2 > in blue on left wing (ie.2B>L), male 1B>L 13.52 [75] 1f on ohd mid-slope by eastern fence of Field Centre enclosure, marked 3B>L 13.57 [76] 1f on ohd near same Field Centre fence, marked 4B>L 14.01 [77] 1f on ohd in grassy area amongst heather midslope, marked 4B>L1B>R 14.04 [78] 1f on ohd mid-slope, marked with blob followed by 2 chevrons on left (ie.B.>>L) 13.16 1f seen on fairly fresh ohd by top birch in valley 13.55 1f on ohd on grassy turf just below eastern fence to Field Centre enclosure

Field 5 Entered 15.43; 15.49 [61] 1m (Recapture) on ocd at bottom of Clearing 2 anthill section, near marsh edge- one open blue circle on right wing (ie.1BOR) (marked on 19 August in Field 1 (east) at 10.57- this had travelled about 500m in about 5 hours- a remarkable feat in so short a time considering the obstacles to straight flight). 15.55 [87] 1f on ohd mid-slope below path in Clearing 2, marked B`XR 15.58 [88] 1f on fairly fresh ohd midfield, west of path near hollow, marked in blue with 2 backward slashes and a X on right wing (ie.B2`XR) 16.01 [89] 1f on ohd south of hollow, marked B3`XR. Exuded white blob 16.06 [90,91] pair on ocd, mid-slope west of path on gorse edge on southern edge of Clearing 2; f marked B4`XR, m marked B5`XR 16.11 [92] 1m on ocd in extreme south-west corner of Clearing 2, south of gate onto Dinam Road, marked B6`.R (ie blob instead of X) 16.16 [93] 1m (very large) on ocd by gate to Dinam Road, marked with 4 red backward slashes and a red apical dot on right wing (ie. B4`R.R) 16.19 [94] 1m (very large) on bramble leaf in small grassy area just south of upper plank bridge over stream (no dung nearby), marked B1XXR 16.27 [95] 1f on grass by marsh-edge at bottom of Clearing l, marked B3`XXR 16.29 [96] 1f (very large) on grass (no dung nearby) in bottom extension of Clearing 1, marked with 4 forward slashes and two X on right wing (ie.B4/XXR) 16.35 [97] 1m (very large) on ocd in middle of Clearing l, marked B1XXX R 16.36 [98] 1f on ocd near previous, with Chorthippus sp. (Acrididae) as prey, marked 2B`3XR 16.40 [99] 1? On grass by path near ocd, marked 2B`R XXL 16.43 [100] 1f on ocd then flew about roadside bushes before landing on grass where it was netted, marked BXXOR 14.22 - 14. 26 five seen on dung as I walked briskly along main path 15.46 one seen on ocd at bottom end of anthill sector near northern end of Clearing 2 15.52 one on ocd on gorse edge in Clearing 2 15.54 one seen on grass just west of path, southern end of Clearing 2 16.04 one seen on grass by path 16.06 one other male on ocd on which pair caught 16.10 one seen on ocd 3m from previous 16.25 one on crusted but not very old cow-pat at bottom of Clearing 1. The dung contained no fly larvae

Mound Entered 16.45; 16.47 [101] 1f (very large) on ohd by brambles in channel, marked BXXOROL 16.53 [101] 1f (Recapture) on ohd by gate- BXXOROL- just marked

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Field 6 Entered 14.54; 14.58 [81] 1f on ocd midfield, marked with 3 backwards slashes on right wing in blue (ie3B`R) 15.13 [82] 1m on ohd by fence in south-east corner, marked 4B`R 15.17 [83] 1f on ocd just by gate into Field 5, marked 5B`R 15.20 [83] 1f (Recapture) on grass 2m north of last- 5B`R-just released 15.23 [84] 1f on ocd midfield, marked 6B`R 15.24 [85] 1f on ohd just down-slope from previous, marked 7B`R 15.28 [86] 1m on ocd down-slope of midfield, marked 8B`R 15.29 [58] 1f (Recapture) on ocd 2m south of previous, flew down-slope onto next pat where caught- 2 open red circles on right wing (ie.2ROR)- (marked on 18 August by gate to fen on eastern edge of Field 6). 14.58 one seen on ocd a metre from end of plank walkway to fen gate 15.04 – 15.10 three seen on ohd along western (roadside) fence 15.10 one seen flying low over grass for several metres near south-east corner

Field 7 Entered 14.28; 14.30 [79] 1f on ohd by telegraph pole in roadside fence, marked with 1 blue line on right wing (ie.1BlR) 14.40 [80] 1? on ohd amongst dead Juncus in north-east corner by marsh edge, marked 2BlR 14.35 one seen on ohd by top fence in extreme north-west corner

Summary for 19 August 41 marked (12m 24f 5?)- Fld. 1(1:1); 2(1m,1?); 3(1m,1?); FC.(1f); 4(2:8; 1?); 5(5:8; 1?); 6(2:4); 7(1f, 1?); Md.(1f). 10 recaptures (1:9)- Fld.1(-); 2(4f- 1 caught twice); 3(-); Field Centre (1-a second recapture); 4(1f); 5(1m); 6(2f); 7(-); Md.(1f). 25 additional sightings- Fld. 1(1); 2(2); 3(2); 4(2); 5(12); 6(5); 7(1); Md.(-). Maximum individuals: 72; minimum: 47. Substrate- ohd- 37; ocd-18; bare ground- 1; grass- 5; bracken-1; bramble leaf- 3; net- 1; in flight- 2. Two pairs in cop.

The recaptures display a remarkable difference in the dispersal behaviour of Asilus. All bar one of these were females and most of these showed a remarkably sedentary disposition, all being recaptured in the same field or an adjoining field to the one in which they were marked on the 18 or 19 August. The male (marked 1BOR), however, showed astonishing dispersal power considering the terrain, travelling about 650m in a mere 5 hours. In contrast the female which travelled the furthest was specimen 5R1R which was marked by the pylon in Field 3 at 15.14 on 18 August and had reached the bracken area at the southern end of Field 2, some 250m south, by 11.39 on 19 August. Female 6BOR.R was marked in the north-west corner of the Field Centre enclosure, was recaptured 4 minutes later 5m to the north-north west of the Field Centre gate in Field 4, and recaptured 3 hours 50 minutes later by the Field Centre drive.

31 August 1999 Windy and rather close, mainly overcast after very dull morning. Marking with black dots, starting on left wing.

Field l entered 12.58; 12.58 [102] 1m on ohd midfield marked 1B.L 13.00 [102] 1m (Recapture) on next patch of horse-dung- 1B.L (just released) 13.02 [103] 1m on ohd near previous marked 2B.L 13.03 [104] 1m on ohd on marsh/scrub edge marked 3B.L 13.06 [105] 1m on ohd where 1B.L was caught, marked 4B.L 13.09 [106] 1f on next dung patch, marked 5B.L 13.10 [107] 1m on ohd in south-west corner where track to pylon starts, marked 6B.L 13.13 [108] pair on ohd a metre or two along this track, f marked 7B.L; (male escaped before I had marked it) 13.16 [105] 1m (Recapture) landed on pat where 6B.L was marked, as I was dealing with 7B.L- 4B.L (just marked at 13.06) 13.20 [109] 1? On ohd in bracken area (left wing slightly crinkled at tip), marked 8B.L 13.28 [43] 1m (Recapture) on dung-patch where 6B.L was marked- N.8R (marked on 2 August in Field 3 (north- west)- so it was at least a month old) 13.31 [110] 1m on ohd in dense bramble and bracken by road fence, marked 9B.L 13.34 [111] 1m on ohd on edge of bracken area, marked 10B.R (note, on right wing) 13.35 [112] 1m on next ohd patch 1m from previous, had Sarcophaga sp. as prey, marked 10B.L

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

13.40 [110] 1m (Recapture) flying over ohd amongst bracken- 9B.L (just marked by the road fence at 13.31) 12.59 one seen on ohd midfield 13.17 one on ohd in bracken area 13.22 – 13.23 two seen on ohd in bracken area 13.22 one seen on dead bracken 13.34 one seen on ohd amongst bracken

Field 2 Entered 13.45; 13.48 [113] 1m on grass, very active, flying around in short bursts around bracken edge above short-grazed part, finally caught on trampled bracken, marked 11B.L 13.50 [114] 1m on bramble leaf above ohd in bracken area, marked 12B.L 13.58 [115] 1f (very large) in trampled bracken near road fence, marked 13B.L 14.03 [116] 1m on ohd in north-east corner by marsh edge, very wary, flying around in short bursts about heather etc, finally caught on bramble etc, marked 14B.L 13.56 one seen on ohd in middle of anthill section

Field 3 Entered 14.08; 14.09 [117] 1f with prey (Sarcophaga sp.) on ohd by entry to field by roadside fence, marked 15B.L 14.12 [118] 1f on ohd midfield marked B.R (ie 1 blue dot on right wing) 14.14 [119] 1m on ohd 4m north of previous, marked 2B.R 14.17 [119] 1m (Recapture) on ohd midfield, stayed on dung under net- 2B.R- just marked 14.21 [120] 1f on ohd midfield, marked 3B.R 14.26 [121] 1f (very large with frayed wings) on ohd near path south-east of midfield, marked 5B.R 14.31 [119] 1m (Second recapture) on ohd just west of pylon- 2B.R (just marked midfield at 14.14) 14.33 [122] 1m on next ohd patch 2m up-slope of previous, marked 6B.R 14.35 [121] 1m (Recapture) on ohd 4m north of previous- 5B.R (just marked midfield at 14.26) 14.27 one seen on ohd on edge of path by rush bed

Field 4 Entered at 14.42; 14.43 [123] 1f (v.large) on ohd 8m north of gate, marked 7B.R 14.47 [124] 1f (v.large) on ohd near path in valley, marked 8B.R 14.48 [125] 1m on ohd by top birch, marked 9B.R 14.50 [126] 1m on ohd in heather area in valley, marked 10B.R 14.52 [126] 1m (Recapture) on ohd amongst heather on west side of path- 10B.R (just released) 14.54 [126] 1m (Second recapture) on ohd in heather area east of path- 10B.R (just released) 14.54 [127] 1f landed on grass a metre from previous, marked 12B.R 15.02 [128] 1m on ohd midfield east of Field Centre, marked 12B.RBlL 15.04 [129] 1m on ohd up-slope of previous, marked 13B.RlL 14.09 [129] 1m (Recapture) on ohd up-slope of previous- 13B.BRlL (just released) 15.10 [130] 1m on stone just north of mid-slope east of Field Centre, marked 15B.R 15.08 one seen on ohd mid-slope in front of Field Centre [seen 15.09] 15.13 two seen on same ohd patch by top birch 16.57 one seen on ohd by top birch 16.58 one seen on ohd by Field Centre gate

Field 5 Entered 15.15; 15.16 [127] 1f (Recapture) on ocd 4m along path from gate- 12B.R (marked at 14.54 in Field 4 valley.) 15.19 [131] 1f on ocd 10m further along path, marked 16B.R 15.21 [132,133] two on ocd in Clearing 1- male and female but not in cop; female exuded black fluid from proboscis, marked 17B.R, male, which was very small, marked 15B.R3B.L 15.25 [134] 1f (very large) on ocd 2m from previous, marked 16B.R4B.L 15.26 [90] 1f (Recapture) on next pat- B4`XR (marked on 19 August in Field 5 north) 15.27 [95] 1f (very large) (Recapture) on ocd in Clearing 1 middle- B3`XXR (marked on 19 August in Field 5 centre) [caught at 15.28] 15.31 [135,136] pair in cop on turf by edge of rushes in bottom of Clearing l; f 11B.R6B.L; m (very large) 10B.XR 15.37 2f on ocd (same pat) near gorse in south of Clearing l:- one [137] marked 17B.R, other [131] female a (Recapture)- 16B.R –marked on path in Field 5 before Clearing l.

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

15.40 [138] 1m on ocd by gorse edge up-slope west of path at northern boundary of Clearing 1- very frayed, having only half of left wing so that it could only fly a matter of inches, marked with large elongate blue mark on right wing- B ~ R 15.43 [139] 1m on ocd a yard or two from previous, marked 12B.R6B.L 15.47 [140] 1f (small) on ocd just up-slope and north-west of plank bridge, marked 12B.R7.L [a dead Staphylinus erythropterus on ocd on northern rim of hollow above path was evidently work of an Asilus] 15.53 [141] 1m on ocd near uppermost gorse by path, marked in blue with 2 blobs followed by numeral 1 on left wing (ie. 2B.1L) 15.56 [142] 1f (very large) on ocd near bottom of slope in Clearing 2, marked 20B.R 15.59 [143] 1m on ocd 10m north of previous along marsh edge, marked with 20 blue dots on right wing, and a large blue blob on left (ie. 20B.R1B.L) 16.02 [144] 1m on fairly fresh horse dung by tp in fence below gate, marked 22B.R3B.L 15.30 one seen on ocd by marsh-edge at bottom of Clearing 1 16.01 one seen on ocd just above marsh edge in Clearing 2. 16.47 one very large female seen on track just inside gate to Field 6 16.49 one seen on path in Clearing 1.

Field 6 Entered 16.04 on way to field 7, then on return at 16.20; 16.28 [148] 1f on ocd by fen walk gate, marked with twenty dots on right wing and a triangle on left (ie.20B.RBAL) 16.26 [149] 1f on ocd in south-east corner by marsh edge, marked with 20 blue dots on right wing and 5 blue dots on left (ie. 20B.R5B.L) 16.33 [150] 1f on ocd by path 30m north of gate, marked 23B.R6B.L 16.35 [151] 1m (small) on ocd by path midfield, marked with blue chevron and triangle on right wing (ie.BVAR) 16.37 [152] 1m on next cow-pat to previous, marked BAVAR [caught at 16.36] 16.41 [153] 1f on ocd with Neomyia sp. as prey about 2m south of previous, marked BAVAR (with another V below middle one) 16.44 [154] 1m on ocd just east of path, about 30m north of gate, marked BAVAL 16.46 [155] 1f (very large) on ocd by path about 25 metres north of gate, marked BAVA.R (ie. Blue blob after second A) 16.04 - 16.07 three seen on ocd along path 16.30 one seen on ocd by gate into Field 5 16.34 one seen on ocd by path about 30m from gate

Field 7 Entered 16.07; 16.07 [145] 1f on muddy track at entrance to Field 7, marked 22B.R4.L 16.09 [146] 1m on ocd by fence beside telegraph pole, marked with blue triangle on left wing (ie.BAL) 16.14 [147] 1f on ocd on edge of rush-bed in north east of field, marked with a blue triangle on each wing (ie. BARBAL)

Mound Entered 16.51; none seen

Summary for 31 August 54 marked (29m,24f,1?)- Fld. 1(8:2,1); 2(3:1); 3(2:4); 4(5:3); 5(7:7); 6(3:5); 7(1:2). 13 recaptures Fld. 1(3); 2(-); 3 (3 including 1 caught twice); 4 (3 including 1 caught twice); 5(4)); 6(-); 7(-). 23. Additional sightings- Fld. 1(7); 2(1); 3(1); 4(5); 5(4); 6(5); 7(-). Maximum individuals: 84; minimum: 59. Substrates- 41 ohd; 30 ocd; grass 7; bare earth 3; bracken 1; stone 1; bramble leaf 1. Two pairs in cop.

Of the recaptured individuals, two were second recaptures, so that in total 11 individuals were involved, a male (N.8R) recaptured at 13.16 near the roadside pylon in the extreme south-west corner of Field 1 had been marked in the north- west corner of Field 3 by the car-park fence on 2 August, about 350m away, 29 days earlier. This is the record for longevity in this species at Crymlyn Bog. Two females (B3`XR and B4`XR) recaptured in Field 5 had been marked in the same field on 19 August, 12 days earlier. Whilst the former had remained in the vicinity of the first clearing, the latter had moved there from the second clearing at the northern end of the field. The remaining recaptures were of individuals marked on 31 August. The most adventurous of these was the female 12B.R which was marked in the valley area of Field 4 at 14.54 and was recaptured 22 minutes later some 40m north, in Field 5, 5m inside the gate from Field 4;

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999 she had clearly proceeded northwards along the path from Field 4. The two individuals which were recaptured a second time had barely moved from the places they had been initially marked, 17 and 6 minutes earlier.

1 September 1999 Warm sunny day. Marking with blue dot followed by numeral on left wing.

Field 1 Entered 12.32; 12.32 pair on ohd on path at field entrance, [102] male (Recapture)- 1B.L (marked on 31 August in Fld.1); [156] female marked B.1L (ie. blue figure 1 preceded by dot on left wing) 12.36 [110] 1m (Recapture) on ohd on path verge just upslope from previous pair- 9B.L (marked on 31 August in Fld. 1 by roadside fence) 12.41 [157] 1m on ohd 5m below midfield, marked B.2L 12.45 [107] 1m (Recapture) on ohd in bracken area- 6B.L (marked on 31 August in Field 1 near pylon) 12.46 [104] 1m (Recapture) on ohd in bracken area- 3B.L (marked on 31 August in Field 1) 12.48 [158] 1m on bare soil amongst bracken, marked B.3L 12.51 [116] 1m (Recapture) on ohd amongst bracken- 14B.L (marked on 31 August in Field 2 north-east) 12.54 [102] 1m (Third recapture) on bracken east of path entrance- 1B.L (marked on 31 August in Field 1) 12.58 [158] 1m (Second recapture) on grass path north of pylon on edge of nettles, bramble, bracken etc.- B.3L (marked at 12.48 close by) 13.00 [104] 1m (Second recapture) on ohd 3m north of previous, on bracken area edge- 3B.L (just released at 12.46 above) 13.03 [156] 1f (Recapture) on ohd on edge of bracken area- B.1L (just marked at path entrance at 12.32) 12.38 one seen on ohd in bracken area 12.40 one seen on ohd on lower grassy slope 12.47 one seen on ohd in bracken area

Field 2 Entered at 13.05; 13.07 [159] 1m on ohd by bracken edge; left wing very frayed, right less so, marked B.4L 13.09 [160] 1? on ohd 2m further into bracken, marked B.5L 13.16 pair (both recaptures) on open grassy area on southern edge of ant-hill section- [103] male 2B.L (marked in Field 1 centre, 35 minutes earlier); [129] female (Second recapture) 13B.R1.L (marked on 31 August in Field 4 centre). [dull now, threatening rain] 13.21 [161] 1? On ohd on bracken edge, marked B.6L 13.26 [112] 1m (Recapture) on trampled bracken near roadside fence- 10B.L (marked on 31 August in Field 1, caught at 13.27) 12.28 – 12.31 two seen on ohd on way through to Field 1 13.12 one seen on track through bracken 13.13 one seen on ohd by pylon 13.16 one seen on ohd in middle of anthill section

Field 3 Entered 13.31; Reporter and photographer were with David Painter and Jo doing a programme for Welsh TV so they were active in this, causing some distraction. 10.30 [162] 1f on ohd midfield caught and retained by David Painter until filmed at midday, marked B.14L 13.32 [163] 1f on ohd by field entrance near roadside fence, marked B.7L 13.35 [164] 1f on ohd 2m north of previous, along road fence verge, appeared to be incapable of flight but was not damaged in any way; marked B.8L. Still on the dung and at end of day, where it had merely moved onto an overhanging bramble leaf but was still extremely lethargic. Specimen taken home to mount to see how well the ink mark persisted. 13.39 [163] 1f (Recapture) on ohd midfield- B.7L (just marked at 13.32) 13.45 [165] 1m on ohd near previous, marked B.9L 13.53 [163] 1f (Second recapture) on ohd near roadside fence B.7L (second recapture of specimen marked at 13.32) [marked at 13.47] 13.55 [166] 1? On ohd midfield, marked B.10L 13.56 [165] 1m (Recapture) on ohd midfield- B.9L (marked same area 11 minutes earlier) 13.57 [165] 1m (Second recapture) on ohd midfield- B.9L (just released) [13.58]

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

14.00 [165] 1m (Third recapture) on ohd midfield (Jo)- B.9L (just released) 14.01 [167] 1f on ohd near scrub on southern edge scrub mid-slope, marked B.11L 14.08 [168] 1f on ohd in heather area north west of pylon (Jo), marked B.12L 14.09 [169] 1f on ohd near scrub on northern edge, marked B.13L 14.14 [163] 1f (Third recapture) on ohd by roadside fence- B.7L 14.35 [170] 1? on ohd midfield (Jo) marked B.15L 14.38 [171] 1f on ohd midfield marked B.16L. Two dead Sphaeridium sp. (Hydrophilidae) on this pat. 14.40 [172] 1f on ohd 1m from one marked at 13.35, marked B.18L. This specimen was evidently in process of ovipositing and was filmed at length for TV by the team. It must have been on the same dung patch for at least half an hour whilst it was being filmed. [c10.00-10.10 seven seen in midfield by D.Painter] 13.51 one seen on ohd in north-west corner 13.53 one seen on ohd near north-west corner 14.44 two seen on ohd midfield [14.46]

Field 4 Entered 17.04; 17.06 [124] 1f (Recapture) on ohd in valley- 8B.R (marked in same area on 31 August) 17.09 [125] 1m (Recapture) on ohd by Field Centre gate- 9B.R (marked on 31 August by top birch in Field 4) [17.08] 17.18 [126] 1m (Third recapture) on ohd on ridge towards wood pile- 10B.R (marked on 31 August in heather area of valley in Field 4) 17.19 [145] 1f (Recapture) on ohd just downslope from previous on marsh edge- 22B.R4B.L (marked on 31 August on muddy entrance to Field 7) 17.23 [123] 1f (Recapture) on ohd in middle of heather area of valley- 7B.R (marked on 31 August in same area) 1727 [126] 1m (Fourth recapture) on ohd by roadside bushes 12m north of Field Centre gate- 10B.R (marked on 31 August in heather area of valley in Field 4). 17.16 one seen on ohd on ridge 17.24 one seen on bare ground on path

Field 5 Entered 16.18; 16.17 [150] 1f (Recapture) on ocd, then flew onto grass, by telegraph pole to east of gate- 23B.R6B.L (marked on 31 August in Field 6 centre) (caught at 16.18) 16.23 [179] 1m on ocd near marsh-edge in Clearing 2, marked B.25L 16.25 [180] 1f on ocd close to previous, marked B.26L 16.28 [181] 1f on ocd slightly upslope of previous, marked B.27L 16.29 pair in cop on ocd just below path in Clearing 2, midway between gate and top gorse (see Fig.4); [182] male marked B.28L; [64] female (Recapture)- four red spots on right wing- 4BO(R.)R (marked on 19 August in bracken area in north-west part of Field 2) 16.33 [144] 1f (Recapture) on ocd by top gorse- 22B.R3B.L (marked on 31 August by gate in Field 5 north.) 16.36 [143] 1m (Recapture) on ocd upslope of path at end of bracken area- 20B.R1.L (marked on 31 August in Field 5 north-east).- 16.45 [183] 1? On ocd bottom of Clearing l on marsh edge with Sarcophaga sp. as prey, marked B.29L 16.48 [184] 1m on ocd in middle of Clearing l, marked B.30L. A dead Hister sp. (Histeridae) on this pat 16.50 [185] 1f on ocd upslope of previous, marked B.31L. 16.22 one seen in Clearing 2 mid-slope 16.23 one seen close to previous 16.27 one seen on ocd midslope in Clearing 2. 16.28 one seen on ocd near previous 16.37 one seen on ocd near road gate 16.47 one seen on ocd near edge of gorse Clearing l [16.42]. 16.45 one seen on ocd mid Clearing 1. 17.00 one on stone in path just right of gate from Field 4

Field 6 Entered 15.51; 15.58 [174] 1m on ocd downslope from gate, marked B.20L 16.02 [175] 1? On ocd 30m north-north-east of gate, marked B.21L

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

16.05 [153] 1f (Recapture) on ocd by angle in roadside fence; very alert, escaped from under net once but finally caught- BAVAR-with second V under middle one (marked on 31 August in Field 6 centre) 16.09 [176,177] 2m on ocd (same pat); one very small with left hind leg missing, marked B.23L, other twice size in bulk, marked B.22L. 16.13 [178] 1m on ocd by roadside fence, marked B.24L 16.15 [175] 1? (Recapture) on ocd a metre or so away from previous- B.21L (marked nearby 13 minutes earlier) 16.17 [177] 1m (Recapture) on ocd just by gate into Field 5- B.23L (the very small one just marked and released). 15.52 one seen on ocd in north-east corner by rushes 16.00 one seen on turf near path towards midfield

Field 7 Entered 15.46; 15.48 [173] 1? On ohd amongst rushes by stream some metres from gate, marked B.19L

Mound Entered 16.53; left 16.56; none seen

Field 9 I had noted on a previous visit that there were horses in the two fields beyond field 7 and had decided to see if Asilus was present in these fields too. Entered field 9 at 15.14 15.14 one on stone on grassy slope below road fence 15.21 one on fairly fresh horse dung by road fence between gate and gorse area

Field 8 15.30 1m on ohd 6 metres in from south-west corner. This had not been marked

Field A This lies across the road from Fields 6 and 7 and is usually grazed by cattle and horses so also quickly checked to establish the presence of Asilus. 15.40 one seen on ocd in rough grassland by fence at northern edge

Summary for 1 September 30 marked (11m, 12f, 7?)- Fld. 1(2:1): 2(1m 2?); 3(1:8,2); 4(-); 5(3:3,1): 6(4m,1?); 7(1?); Md.(-). 31 recaptures (18m 12f 1?)- Fld. 1(8:1); 2(2:1); 3(3:3); 4(3:3); 5(1:3); 6(1:1,1), 7(-); Md.(-), including 5 second recaptures- Fld. 1(2); 3(3), 3 third recaptures- Fld. 1(1); 3(1); 4(1), and 1 fourth recapture (Fld. 4). 28 additional sightings- Fld. 1(3); 2(5); 3(4); 4(2); 5(8); 6(2); 7(-); Md.(-); also in fields at northern end- Fld. 8(1); 9(2); 10(1). Maximum individuals: 75; minimum: 51. Substrate- ohd- 45; ocd- 24; ground- 5; stone- 1; leaves-2 (1 bracken, 1 bramble leaf).

Of the recaptured individuals five were recaptured a second time (B.3L, 3B.L, 13B.R1B.L, B.7L, B.9L), four a third time (10B.R, 1B.L, B.7L, B.9L) and one a fourth time (10B.R). Two individuals were noteworthy, both females: specimen 4BO(R.)R was marked in the north-western corner of Field 2 and recaptured some 400m to the north-west, at the northern end of Field 5, two weeks later. Specimen 22B.RB4.L was marked at 16.07 at the entrance to Field 7 on 31 August and at 17.19 next day had reached the marsh edge in Field 4, a distance of over 520m. The remaining individuals were all recaptured close to the places they were marked, most having remained in those areas apparently for upwards of 24 hours.

10 September 1999

Warm sunny day with slight southerly breeze, c.18oC. Marking with numeral only, in blue (ie. no preceding dot as was the case with those marked on 1 September 1999.

Field 1 Entered 10.14; 10.21 [186] 1m (wings not frayed) on ohd north-west corner amongst bracken, marked B1R 10.22 [186] 1m (Recapture) on ohd 30cm from previous- B1R- just released (marked at 10.23)

Field 2 Entered 10.31; 10.32 [187] 1f on bare soil on upper horse-track through bracken, on extreme southern edge by entry to Field 1, marked B2R 10.37 [188,189] 2m (only one seen) on same ohd as one seen at 10.15- perhaps including same individual; first (frayed wings) marked B3L, other (wings less frayed) marked B4L

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

10.47 [190] 1m on dead bracken in horse-track, marked B5L 10.15 one seen on ohd on edge of bracken at outhern end, in anthill section

Field 3 Entered 10.52; 11.07 [191] 1m on ohd amongst heather, rushes, young gorse etc mid-way between telegraph pole and trees on northern edge, marked B6L 11.11 [192] 1f on ohd 3m south-south-west of previous, on edge of same bed of heather. Marked B7L 11.00 one seen on ohd by tp 11.02 one on ohd 5m north of previous 11.05 one seen on same dung patch

Field 4 Entered 11.15; 11.15 [193] 1m on ohd in rough edge north of Field Centre of gate, marked B8L 11.23 [194] 1f on ohd on path edge 2 yards into valley, marked B9L 11.29 [195] 1f on ohd near southern scrub edge, marked B10L 11.30 [196] 1? On ohd 4m north of previous, marked B11L (marked at 11.31) 11.33 [197] 1? On ohd 2m north of previous, marked B12L 11.34 [198] 1m on next dung patch to previous- half a metre up-slope, marked B13L 11.39 [199] 1f (frayed wings) on ohd on ridge south of second birch, marked B14L 11.45 [200] 1f on grass verge of path at northern end of bridge over stream, marked B15L 11.22 one seen on ohd by path at crest of slope north of Field Centre of gate

Field 5 Entered 11.47; 11.50 [201] 1m on ocd (slightly frayed wings) by path at northern edge of Clearing 1, west of path, marked B16L 11.51 [202] 1f (pristine) on ohd on opposite (east) side of path to previous (marked B17L; marked at 11.52) 12.04 [203] 1? On ocd by telegraph pole in fence below gate, marked (in error) B17L [a dead Aphodius fimetarius (Scarabaeidae) beside this fly.] 11.54 one seen on ocd up-slope of that marked at 11.51 12.33 one seen on bare soil on path at southern end of Clearing 2

Field 6 Entered 12.18; The wind had freshened considerably and was sweeping westwards across this field. The only Asilus seen were along the roadside fence at the western edge, whence perhaps they were drifting under the influence of the wind. 12.18 [204] 1f on ohd by roadside fence with Aphodius contaminatus (Scarabaeidae) as prey, marked B18L 12.22 [204] 1f (Recapture) on grass 5m south of previous- B18L just released 12.26 [205] 1? On ocd by roadside fence, marked B19L 12.28 [206] 1m (very small) on bare soil just inside gate, marked B20L 12.19 one seen on ohd next to 12.20 specimen

Field 7 ; walked round field from 12.15 to 12.17- none seen

Mound; none seen between 12.37 and 12.42

Summary for 10 September 21 marked (9m, 8f, 4?)- Fld. 1(1m): 2(3:1); 3(1:1); 4(2:4,2); 5(1:1,1): 6(1:1,1); 7(-); Md.(-). 2 recaptures (1m 1f)- Fld. 1(1m); 5(1f). 5 additional sightings- Fld. 2(1); 3(3); 4(1); 5(2); 6(1). Maximum individuals: 26; minimum: 21. Substrate- ohd- 21; ocd- 3; bare ground- 3; bracken 1, grass 1.

The two recaptured individuals had both only been marked a minute or two before and had barely moved any distance.

11September 1999

After dull morning misty sun coming out but still overcast. In those marked on this date, a dot precedes the numeral, which is in blue on the left wing.

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Field 1 Entered 12.46; 12.48 [105] 1m (Second recapture) on ohd amongst bracken just east of entrance- 4B.L (marked on 31 August in middle of Field 1, about 10m to south) 12.55 [208] 1m on ohd on grass-path by pylon in south-west corner, marked B.51L in blue with number 51 preceded by dot (ie. B.51L) (caught 12.56) 12.59 [209] 1f (in pristine condition) on grass path by pylon a metre or so to south of previous, marked B.52L 13.02 [163] 1f (Fourth recapture) on ohd by entry to Field- B.7L (marked on 1 September by roadside fence in Field 3) 12.46 one on ohd at entrance to Field 1 12.56 a female landed on net whilst I was marking B.51L, then immediately flew off again

Field 2 Entered 13.04; 12.42 [207] 1f on ohd in north-west corner of field on edge of bracken area, marked B.50L [I was on way down to Field 1] 13.14 [210,211] 2f on ohd amongst bramble and bracken etc in marshy north-east corner, marked B.53L (pristine condition) and B.54L (frayed). 13.09 one seen on ohd in middle of anthill section

Field 3 Entered 13.22; 13.24 [212] 1m on ohd midfield, marked B.55L 13.24 [213]1m on ohd 4m to south of previous, marked B.56L. (13.26, not 13.25) 13.28 [66] 1m (Second recapture) on ohd 3m upslope of previous, beside a dead female Tipula paludosa (Tipulidae); marked 6 black circles on right wing (marked on 19 August in same place- middle of Field 3; it was marked in blue originally (6BOR) but colour changed. Wings slightly frayed0. 13.33 [214] 1f (rather small, with frayed wings) on ohd 3m from previous, marked B.57L 13.36 [215] 1f on ohd below path, 4m north-north-west of telegraph pole, marked B.58L (wings not frayed). 13.37 [182] 1m (Recapture) on ohd 4m from scrub on northern edge, 10m north-north-west of telegraph pole- B28L (marked on 1 September at north end of Field 5; wings not frayed but a small hole in discal area of right wing) (caught 13.39) 13.40 [216] 1m on fairly fresh horse dung 4m nearer telegraph pole than previous, marked B.60L. (Specimen had tip of left wing missing and a hard white blob in centre, presumably exuded by the fly.) (Caught at 13.41, not 13.40) 13.42 [217] 1f on next ohd down-slope, marked B.61L; had small piece missing out of right wing 13.46 [215] 1f (Recapture) on ohd by scub on northern edge- B.58L (the code was barely visible although it had been marked only 10 minutes earlier- see under 13.36 above)

Field 4 Entered 13.50; 13.49 [200] 1f (Second recapture) on ohd (very small, wings extremely frayed) right by entrance from Field 3- B.15L (marked on 10 September at northern end of bridge on path in northern end of Field 4) 13.55 [199] 1m (Recapture) on ohd near wood-pile at bottom of ridge. Marking extremely faint but looked like 14 on left wing- colour dark but faint- presumably blue or black; presumably B14L marked on 10 September in same area of Field 4). 14.00 [147] 1f (Recapture) on ohd on ridge- BARBAL (marked on 31 August on the edge of the rush bed in the north-east corner of Field 7 14.04 [218] 1m on ohd in valley, west of path, marked N.62L (decided that the blue pen was unreliable) 13.50 one seen on ohd by path entrance from Field 3 14.01 1m on ohd then flew onto grass and away, south of lower birch

Field 5 Entered 14.15; 14.16 [219] 1f (pristine) on ohd above path at northern end of Clearing 1, marked N.63L 14.21 two seen in flight by gorse in southern part of Clearing 2 14.29 one seen on ohd in middle of Clearing 2

Field 6 Entered 14.30; no Asilus seen

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Summary for 11 September 13 marked (5:8)- Fld. 1(1:1); 2(3f); 3(3:3); 4(1m); 5(1f). 8 recaptures (3:4)- Fld. 1(1:1); 2(2:1); 4(2f), including 3 second recaptures (in Fds. 1, 3 and 4) and 1 fourth recapture (in Fld. 1). 3 additional sightings- Fld. 1(2); 2(1). Time spent in each field- Fld. 1(15); 2(10); 3(25m); 4(15m); 5(15m); 6(10m). Substrates- ohd 23; in flight 2; grass 1; on net 1. Maximum number of individuals: 24, minimum: 21.

Of the recaptured specimens, one (B.58L) had been marked 10 minutes earlier midfield in Field 3. Of the two caught in Field 1 (4B.L and B.7L), the former (marked on 31 August) was retrieved 10m from the place in Field 1 in which it had been marked 12 days earlier. B.7L which was marked on 1 September by the roadside fence in Field 3, had travelled some 250m southwards. Specimen 6BOR appeared to have stayed around the middle of Field 3 since it was marked on 19 August (ie. 24 days earlier). The remainder had moved southwards since they were marked, viz.- a) B16L, marked on 10 September, had moved to the southern edge of Field 4 from Clearing 1 in Field 5, b) B28L had reached Field 3 from the northern end of Field 5 in the 10 days since it was marked on 1 September, c) the female BARBAL, marked on 31 August on the track at southern entrance to Field 7, had reached the bottom end of the ridge in Field 4, some 550m to the south-east, by 11 September (ie, 12 days later).

Summary of totals for Crymlyn Bog NNR

11 visits made: 27, 30 and 31 July, 2, 11, 18, 19 and 31 August, 1, 10 and 11 September.

222 Asilus marked: 102m:101f,19? - Fld. 1(23); Fld. 2(22); Fld. 3(43); Fld. 4(53); Fld. 5(43); Fld. 6(25); Fld. 7(6); Md.(6); Field Centre (1); one died in the hand whilst marking, another was dying in field when marked, so 220 were available for recapture.

64 individuals recaptured: 47 recaptured once, 11 twice, 4 three times and 2 four times.

Substrates: ohd, 276 observations; ocd, 90 observations; grass, 11 observations; bare earth, 17 observations; bracken, 5 observations; stones, 4 observations; in flight, 5 observations; bramble, 3 observations; crow-feather on ground, 1 observation; on sweep-net, 2 observations.

Maximum number of individuals: 425, minimum: 222.

Of the 64 recaptured individuals, 22 were last seen on the day of marking, 25 a day later, 1 two days later, 3 three days later, 1 four days later, 1 six days later, 3 ten days later, 4 twelve days later (including one recovered on Kilvey Hill), 1 thirteen days later, 1 fourteen days later, 1 twenty-three days later and 1 twenty-nine days later.

174 additional sightings: Fld. 1(22); Fld. 2(23); Fld. 3(25); Fld. 4(35); Fld. 5(40); Fld. 6(22); Fld. 7(1); Md.(2); Fld. 8(1); Fld. 9(2); Fld. 10(1).

Time spent: 28hrs55mins: Fld. 1(3h16m); Fld. 2(4h10m); Fld. 3(5h.45m); Fld. 4(4h.55m); Fld. 6(3h15m); Fld. 7(1h); Md.(1h); Field Centre (10m); Fld. 8(10m); Fld. 9(10m); Fld. 10(5m).

2) Kilvey Hill (P Skidmore)

The area of Kilvey Hill in which the mark-recapture exercise was carried out was in Fields C to G shown on the sketch- map (Fig.1)

30 July 1999

Field C 16.32 [K230] 1? on ohd on tree-edge above ravine in extreme north-east corner, marked 11N.R

Field D Walked up slope from bottom telegraph pole. Specimens marked with black blobs on right wing 14.45 [K220] 1? on ohd about 35m up-slope of lower telegraph pole, marked 1N.R 14.56 [K221] 1m on ohd just below grass path from pylon, marked 2N.R

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

15.27 [K222] 1m on stone in uppermost corner by fenced junction at upper wood edge, marked 3N.R 14.49 one seen on ohd 30m west-north-west of lower telegraph pole, flew onto ohd about 5m up-slope of dung pat where 1N.R was marked 14.52 one seen on ohd about 5m further up-slope 14.54 one seen on ohd about 5m up-slope again 14.56 one male seen on ohd about 5m up-slope again 15.00 – 15.20 five seen on ohd along grass path to top fence boundary 16.25 – 16.30 three seen on ohd between top fence and bottom tp

Field G central area consists of heather and gorse clad mound on top of which is the enclosed electricity substation. 15.41 [K223] one on ohd marked 4N.R 15.39 one seen on ohd in heather area 15.42 one seen on ohd in heather area 15.50 one seen on ohd in north-east corner of field

Field F Like field E without heather or bracken areas but with rough grassland around edges 16.00 [K224] 1m on ocd in rough by top gorse, marked 5N.R (marked at 16.00.) 16.05 [K225] 1f on ocd in rough midfield marked 6N.R 16.10 [K226] 1? On ocd by track over northern edge wall-line by brambles, marked 7N.R 15.30 one seen on ocd 15.56 one seen on ocd on southern edge by top gorse on fence-line 16.06 – 16.10 two seen on ocd in rough on northern edge

Field E 16.16 [K227] 1f on ocd midfield rough, marked 8N.R 16.17 [K228] 1f on ocd 3m from previous, marked 9N.R; vegetation in rough included-Holcus lanatus, Lotus corniculatus, Trifolium repens, Leontodon sp., Senecio jacobeae, Plantago lanceolata etc. 16.22 [K229] 1? on ocd in rough 2m from previous marked 10N.R

Summary for 30 July 11 marked- Fld. C(1?); D(2m,1?); E(2f,1?); F(1:1,1); G(1?). 20 additional sightings- Fld. D(12); E(-); F(5); G(3). Substrates- ohd- 15; ocd- 10; stone- 1.

31 July 1999 Specimens marked in green with blob followed by a letter (ie. A to Z) on right wing.

Field 1c 15.14 [K231] 1m on ohd by tree edge above ravine in extreme north-east corner, marked dot A in green on right wing (ie, G.AR)

Field 1b 15.30 [K232] 1? on ohd on grass path 5m after divergence of paths south of pylon, marked G.BR 15.37 [K233] 1m on ohd by top fence 30m north of wood edge, marked G.CR 15.40 [K234] 1m on same pat as previous, marked G.DR 15.20 – 15.28 three seen on ohd between bottom telegraph pole and pylon 15.45 one seen on stone in south-east corner by fence flew up onto a sweet chestnut leaf then southwards along woodland edge

Field E 15.46 [K235] 1m on ocd on field edge about opposite one where G.CR and G.DR were marked; this male marked G.EER (first E blotched so did second E) 15.53 [K228] 1f (Recapture) on ocd near previous- 9N.R. (marked on 30 July in Field E). 15.58 [K236] 1m on ocd in same rank herbage area midfield, marked G.FR 16.58 [K241] 1m (Recapture) on ocd in midfield rough- G.KR (marked on the northern edge of Field 3, some 50m to the south, 42 minutes earlier). 17.04 [K253] 1? on ocd in extreme north-east corner, by fence, marked G.YR

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

17.05 [K254] 1? on ocd further west along fence, marked G.ZR 15.50 one seen on ocd in rank herbage midfield 16.59 one seen on ocd in same area as previous

Field F Separated from Field E by old wall but no fence. There were cattle in this field on this visit 16.01 [K237,K238] pair on ohd by cattle track over wall line on upper edge of tangle of bramble, gorse etc., f marked G.GR, m marked G.HR 16.07 [K239] 1f on ohd a metre up-slope from previous pair, marked G.HR (in error). (marked at 16.08). 16.12 [K240] 1? on ohd in north-west field corner (junction of old wall lines), marked G.JR. (marked at 16.12) 16.16 [K241] 1f on ohd 5m south along this edge, marked G.KR 16.17 [K242] 1m on ohd 8m further south, marked G.MR 16.20 [K243] 1m, about 2m north-north-west of top gorse, marked N.LR (green pen temporarily mislaid) 16.46 [K249] 1m on dung pat where one seen at 16.20, marked G.TR 16.47 [K250] 1m on next ohd pat to previous, marked G.UR 16.52 [K251] 1? on ohd midfield rough, marked G.VR 16.55 [K252] 1m on ohd by where pair marked at 16.01, marked G.WR 16.20 one seen on ohd on southern edge by top gorse in boundary fence 16.56 one seen on cattle track over wall by top gorse

Field G Separated from Field F by old wall along which a fence runs; towards eastern end a scrubby promontary from the upper woodland edge separates the fields, at the end of which is a gorse bush, referred to here as the ‘top gorse’ 16.25 [K244] 1f on ohd 10m above top gorse, in rough, marked G.NR 16.28 [K245] 1f on ohd 4m up-slope of previous in rough, marked G.OR 16.32 [K246] 1m on ohd by gorse on top of mound marked G.PR 16.37 [K247] 1m on ohd near previous, marked G.RRR (first R obscure so did a second R) 16.39 [K248] 1f on path between upper and lower gorse clumps, marked G.SSR (first S obscure) 16.22 one seen on ohd in rough herbage just above top gorse 16.30 one seen on ohd near north-west corner of field 16.40 – 16.42 three seen on ohd in heather area north of lower gorse clump

Summary for 31 July 24 marked- Fld. C(1m); D(2m,1?); E(2m,2?); F(5:3,2); G(2:3). 2 recaptures- Fld. E(1f,1?). 13 additional sightings- Fld. D(4); E(2); F(2); G(5). Maximum individuals: 31; minimum: 23. Substrates- ohd- 29; ocd- 8; bare earth- 2.

2 August 1999 Marking in black, with blob followed by numeral on left wing

Field C 17.30 [K265] 1? On ohd in extreme north-east corner, on tree edge above ravine where path from road enters field, marked N.11L 16.28 one seen on ohd on wood-edge above ravine

Field D 16.53 [K255] 1m on ohd near top fence, marked N.1L 16.56 [K256] 1m (very small and faded but very active) on ohd near top fence, marked N.22L (first 2 blotched) 17.00 [K257] 1m on ohd by top fence, marked N.3L 17.04 [K258] 1f on stone by top fence, marked N.4L 17.25 [K264] 1m on ohd on slope midway between pylon and bottom tp, marked N.10L 16.54 one seen on ohd by top fence 17.02 – 17.03 three seen on ohd by top fence 17.20 one seen on ohd by top fence

Field E 17.08 [K259] 1m on ocd in midfield rough, marked N.5L

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

17.10 [K260] 1m on ocd a metre from previous, marked N.6L 17.11 [K261] 1? On next pat, a metre away, marked N7.77L (had great difficulty marking this one as pen blotched badly) (marked at 17.12) 17.16 [K262] 1f on ocd by fence separating Fields 1b and 2, marked N.8L 17.19 [K263] 1f on ocd in rough by boundary fence with Field 1b, marked N.999L (several attempts at writing 9 - pen blotching badly) 17.05 – 17.06 two on ocd by boundary fence with Field 1b 17.16 one seen on ocd further west along fence 17.18 one seen on ohd by telegraph pole

Summary for 2 August 11 marked- Fld. C(1?); D(4:1); E(2:2,1). 10 additional sightings- Fld. C(1); D(5); E(4). Substrates- ohd- 12; ocd- 8; stone- 1.

10 September 1999 Marking with numeral from 21 onwards preceded by blob, in blue on right wing

Field C Entered 12.48; sheltered and very warm 12.46 [K266] 1f (wings unfrayed) flying amongst heather, mid-slope on edge of wooded ravine, with m Tipula paludosa as prey, marked B.21L (marked at 12.48) 12.57 [K267] 1m (frayed wings) on grass 10m up-slope on tree edge, marked B.22L 12.58 one m seen on grass midfield

Field D Entered 13.00; 13.01 [K268] 1m on ohd by north-western edge by trees bordering Field 1a, marked B.23L 13.04 [K269] 1f (frayed) on ohd flew off up-slope, dung-hopping, caught on third pat, marked B.24L 13.12.1 [K270] 1f (very large) on ohd where B.24L was marked, marked B.25L 13.18 [K271] 1f on ohd on grass path south of pylon, marked B.26L 13.25 [K272] 1m on next ohd to south of previous on grass path, marked B.27L 13.27 [K273] 1m (frayed wings) on ohd 30m up-slope, just below brow of slope, marked B.28L 13.32 [K274] 1m on ocd at top of grass path between heather beds, marked B.29L 13.35 [K275] 1m on ohd amongst heather close to previous, marked B.30L 13.41 [K276] 1m on ohd on dung-strewn path along top fence, marked B.31L 13.43 [K277] 1f on stone by top fence, marked B.32L 13.45 [K278] 1m on ocd on path by top fence, marked B.33L 13.47 [K279] 1m on ocd on path by top fence 2m further east of previous, marked B.34L 13.12 one m on grass on rim of pit caught escaped whilst I was manipulating it for marking

Field E Entered at 13.50; The upper parts of this field were noticeably windier and cooler so I concentrated more on the lower parts benefiting from the shelter of the upper edge of the sweet chestnut wood. 13.51 [K280] 1m (wings unfrayed) on ocd 5m in from northern fence (separating Fields 2 and 1b, and 15m up-slope from wood edge, in area of short-grazed turf, marked B.35L 13.58 [K281] 1f landed on ocd beside me whilst I was marking previous one, marked B.36L . 14.05 [K282] 1m on ocd 1metre from wood edge, marked B.37L (marked at 14.07) 14.10 [K283] 1m on ohd in rough vegetation by old wall separating Fields 2 and 3, marked B.38L

Field F Entered 14.13; 14.12 [K284] 1f on stone on rough vegetation by old wall separating Fields 2 and 3, marked B.39L 14.15 [K285] 1m on ocd 1m away from previous, marked B.40L 14.17 [K286] 1m on ohd 1m away as I was marking B.40L. This had frayed wings and was marked B.41L 14.22 [K287] 1m on ocd by track over wall-line by brambles etc., marked B.42L 14.25 [K288] 1? on ocd by west wall, by brambles etc, marked B.43L 14.29 [K289] 1f (unfrayed) on ocd a few metres south of previous, but still in rough, marked B.44L 14.32 [K290] 1m (wings slightly frayed) on ocd by wood-edge, 5m north of boundary fence with Field 4, marked B.45L

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

14.36 [K291] 1m on ocd 4m up-slope of previous. B.46L 14.40 [K292] 1? (badly frayed wings) on ocd just by southern fence at level of top gorse (see map 1), marked B.47L [A dead Platydracus stercorarius was found on an old cow-pat by the fence at the uppermost south-western corner of this field, some 10m up-slope from previous; presumably the work of an Asilus.]

Field G Entered 14.42; left at 15.06 to walk across Kilvey Hill to the western end. 14.49 [K293] 1m (wings unfrayed) on ocd on northern edge of electricity substation mound, marked B.48L 14.53 [K294] 1f (wings rather frayed) on ohd on path through heather area on mound, marked B.49L 15.00 [K295] 1m on ocd on path through heather area, marked B.50L. [This managed to pierce my finger but it was barely perceptable. This had happened on two previous occasions during the study, and on all occasions I could barely discern any sensation.] 14.52 one seen on grass near one where B.48L marked 14.57 one seen on fairly fresh horse dung beside the fence of the electricity substation in gorse area

Summary for 10 September 31 marked- Fld. C(1:1); D(8:4); E(3:1); F(5:2,2); G(2:1). 2 additional sightings- Fld. C(1); D(1); G(2). Substrates- ohd- 11; ocd- 15; stones- 2; grass- 1.

11 September 1999 Marking with black dots on right wing

Field 4 Arrived at electricity substation mound at 14.59 to work back northwards. 15.01 [K301] 1f on ohd in a small clearing in the gorse clump by substation fence, marked 5N.R 15.05 [K302] 1m (very frayed wings) on ocd mid-slope path-side below upper gorse patch, marked 6N.R. 15.09 [165] 1m (Recapture) on ohd by lower gorse patch- black dot followed by figure 4 or 9 on left wing N.9L. (This individual could only have been the male marked B.9L in Field 3 in Crymlyn Bog SSSI at 13.45 on 1 September. This was the only specimen marked with a blob followed by a single figure 9; the blue ink had been found to discolour to black in other specimens which have been recaptured). 15.12 [K303] 1f on ohd in north-east corner of wood by upper edge of wood, marked with 7 dots on right wing (ie.7N.R) 15.13 [K303] 1f (Recapture) on grass 1 metre to north of previous- 7N.R, just released. 15.01 one specimen flew around small clearing whilst I was concentrating on other specimen, buzzed under roof of burnt-out car amongst the gorse then made off over the bushes

Field F Entered 14.42; 14.44 [K296] 1m (frayed wings) on ocd midfield, marked N6R4L 14.50 [K297] 1m on ohd in rough herbage by top gorse on fence-line, marked 2N.R 14.51 [K298,K299] pair in cop on ocd 2m up-slope of previous, m (very slightly frayed wings) marked 3N.R, f marked 4N.R 14.54 [K300] 1m (very frayed wings) on ocd 4m up-slope of previous, marked 1N.L 15.19 [K304] 1m on ohd near top gorse on fence-line, marked 8N.R 14.45 one seen on ocd by track over wall line from Field 2 14.52 one female landed on net whilst I was marking the pair above, and immediately flew off again 15.28 1m on ocd on track into Field 2 at junction of wood-edge and wall 15.30 – 15.35 three seen on ohd but extremely wary and fast - impossible to approach closer than 5m. A remarkable and sudden change in behaviour was noted, possibly due to the weather which suddenly became duller and threatened rain. The flies appeared to have become more alert and the slightest movement put them to flight. They were probably about to fly for cover, certainly suddenly they were far less in evidence.

Field 2 Entered 15.35; 15.39 [K305] 1? (frayed wings) on ohd in north-west corner of field, marked 4N.L

Field D Entered 15.42; at 15.58 it started to rain quite heavily and I left. 15.54 [K306] 1f on ohd below grass path south from pylon, just north of top hawthorn, marked 10N.R (caught at 15.55)

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

15.58 [K307] 1m on ohd just to south side of same tree, marked with 10 black dots on right wing and 1 on left (ie.10N.R1N.L). 15.49 one seen on stone on grass path mid-slope, flew off whilst I was still several yards away

Summary for 11 September 12 marked (5:5,2?)- Fld. D(2f); E(1?); F(4:1:1?); G(1:2). 2 recaptures(1:1) in Fld. G. 8 additional sightings- Fld. D(1); F(6); G(1). Substrates- ohd- 12; ocd- 6; grass- 1; in flight- 1; stone- 1; on net- 1. Time spent Fld. 1b(16mins); 2(7mins); 3(30mins); 4(10mins). Maximum individuals: 20, minimum: 12.

Both of the recaptured individuals were in the mound area of Field G. One ((7N.R) had just been released nearby, but the other (N.9L) could only have been specimen 165 which was marked in Field 3 of Crymlyn Bog SSSI on 31 August. This provides proof of movement between the Kilvey Hill slopes and the population in the SSSI. The colour of the ink appeared to be black on the recaptured individual, but was blue when originally marked (ie B.9L). It was found during the study that the pigment in the inks used was very unstable. B.9L was the only individual marked in either the SSSI or on the Kilvey Hill slopes in which the numeral 9 was preceded by a dot. Note that the ninth in the series marked on Kilvey Hill on 2 September (ie.K263), was marked 9.99 on left wing.

By far the most likely route taken by B.9L would have been via the extreme south-western corner of Field 1 and across Dinam Road into the bottom of Field H, a distance of some 550m. Interestingly another individual marked in Field 3 (N.8R ) completed the first part of this journey, reaching the vicinity of the pylon in the extreme south-western corner of Field 1, suggesting that this is perhaps a frequently used flight-line.

Summary for Kilvey Hill

Five visits- 30 and 31 July, 2 August, 10 and 11 September.

77 marked (38m:28f, 14?): Fld. C(5); D(25); E(17); F(18); G(12).

4 recaptures- Fld. E(1:1); F(1:1).

55 additional sightings- Fld. C(2); D(23); E(7); F(6); G(10).

Substrates: ohd- 57; ocd- 38; bare earth- 2; stones- 3; grass- 1; on net- 1; in flight- 1.

Time spent: total 7hrs 40mins- Fld. C(30mins); D(1hr16mins); E(47mins); F(2hr10mins); G(1hr10mins).

Maximum individuals: 132; minimum: 77.

The proportion of marked individuals recovered here was very much less than in the Crymlyn SSSI, namely 5%, compared with 29% on the reserve.

3) Brockwell’s Meadows (D K Clements)

28 June 1999 c 15.00hrs. Warm but overcast conditions, with slight breeze occasionally gusting.

Site inspection only: no Asilus seen.

Five bullocks present in main field (Banky Field) – very boisterous. Dung pats rather scarce on main slope, concentrated along favoured, flatter, upper parts above break in slope, probably where cattle shelter under adjacent overhanging woodland. Counts indicated an average of about 6 pats per 10m2. Sward locally tall and rather rank – cattle evidently only recently introduced to Banky Field.

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

27 July 1999 c 15.30hrs. Hot, sunny day with little cloud; still.

Cattle now taken off. Sward in good condition, moderately well-grazed but with patches and tufts of taller stems. Dung pats moderately frequent, with lots in dry condition preferred by Asilus. Cattle now in Cherry Tree Field, and both this and Middle Field have been cut for hay.

No mark-recapture carried out. Transect-count done on main slope, yielded 2 females, 2 males, 2 unsexed and 1 pair in cop – total 7 individuals, all in pristine condition.

One male observed on medium dry dung pat, leg-washing (rear legs) and sunning. An Aphodius dung-beetle emerged from the dung immediately behind the Asilus and took off. Male Asilus immediately took off in pursuit and intercepted, but did not capture it. Returned to pat to continue leg-washing for 5mins or so, then moved to another pat about 2m away and continued sunning.

Female observed on dry pat, sunning, oriented with head towards sun. Stayed in same position for 15mins, and was still in place when observation ceased.

29 July 1999 c15.30hrs. Warm and sunny, with slight breeze. Marked Asilus, using combination of white blob on thorax to indicate day (‘day-mark’) and black bands on wings to indicate number (left, units of 5; right, units of 1). Day-mark on right humerus of thorax. 13 Asilus marked. Observations:

1) Female: when released took off near crest of main slope and headed straight for cover of adjacent woodland, disappearing into the canopy. 2) Female; during marking, appeared to offer ovipositor as if to ‘sting’ – deterrance behaviour? 11) Female: broke way before wing markings completed, so had same code as No. 1, but left behind left hind-leg so could be distinguished from No. 1 in short term.

13 Asilus marked (5male, 8 female) 6 others seen but not captured ______19 Total

30 July 1999 c15.00hrs. Hot and sunny, still. Air temperature about 32oC. Two hours on site (ie 15.00 – 17.00). Day-mark on left humerus of thorax. 11 Asilus marked. Observations:

Adults observed to be keeping primarily to the upper, flatter part of the main slope of Banky Field, adjacent to the woodland although not in shade. This is where the greatest concentrations of dung were found, especially in the eastern corner.

11 Asilus marked (7 male, 4 female) 3 marked Asilus seen/caught, dating from 29/7 12 others seen but not captured ______26 Total

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

1 Aug 1999 c15.00hrs. Hot and sunny, still. Air temperature 27oC. Two hours on site (ie 15.00 – 17.00). Day-mark on centre of thoracic dorsum. 18 Asilus marked. Observations:

One individual when disturbed, seen to fly directly into the canopy of the adjacent woodland. One individual when disturbed, seen to fly directly into the canopy of adjacent tall hedgerow. Two individuals first seen perched on foliage at edge of woodland, one of which moved from one leaf to another 2m away when approached. Apparently sunning in these positions. Slightly greater observed tendancy this year to perch on substrates other than dung platforms, as compared with previous years. Male seen with Chorthippus parallelus (Acrididae) as prey. All of marked individuals were captured on upper part of slope.

18 Asilus marked (10 male, 8 female) 2 marked Asilus sen/caught, dating from 30/7 18 others seen but not captured ______38 Total

2 Aug 1999

14.30hrs. Sunny and warm, but with some cloud and slight breeze, getting coolor later. Brief revisit to carry out recapture exercise, but no new flies marked on this day. Observations:

Most of activity concentrated on upper part of main slope, far fewer Asilus seen on the lower slope, even though there is dung in asuitable condition: this is contrast to prevous years. Marked individuals seemed to be behaving normally, sunning and interacting in usual fashion. However, noted that the white day-mark was quite visible at a distance, which could potentially affect the cryptic capabilities of marked flies rendering them more vulnerable to predation.

5 marked Asilus seen/caught, dating from 1/8 21 other Asilus seen but not captured (7 male, 11 female, 1 unsexed, 1pair in cop) ______26 Total

31 Aug 1999

14.30hrs. Warm and sunny, but with slight breeze, becoming cooler. First vsit to site after a braek of several weeks. Observations:

Female marked on 29 July (Trh R3) seen on upper slope, indicating longevity of 34 days. The specimen was well-worn, with frayed wing-tips, especially on the right side. Day-mark had dulled to slightly brownish, but this and wing-bands still visible Female No. 6 marked on 31/8 (Tp L1 R1) captured midway between upper edge of field and break of slope observed to fly directly away into woodland canopy when released.

12 Asilus marked (6 male, 6 female) 1 marked Asilus caught, dating from 29 July 2 others seen but not captured ______15 Total

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

1 Sept 1999

15.00hrs. Much cooler day, breezy, with only occasional sun through clouds. Probably near lower limit for Asilus activity. Brief visit to carry out recapture exercise only, with no new flies being marked.

2 marked Asilus seen/captured, dating from 31/8 9 others seen but not captured (6 male, 4 female) ______11 Total

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

APPENDIX 2: TABULATED RESULTS

No./Sex Code No. Date marked: Time: Field No. Recapture Date: Time: Field No. CRYMLYN BOG SSSI 1 f 1GlR 27.7: (12.50): 3c 2 m 2G1R 27.7: (12.55): 3c 27.7: (14.29): 3c 30.7: (11.45): 2c 3 m 3GlR 27.7: (13.41): 3c 31.7: (14.21): 4n 4 m 4GlR 27.7: (13.49): 3ne 5 f 5GlR 27.7: (13.56): 3c 6 f 6GlR 27.7: (14.11): 3c 7 m 1GlL 27.7: (14.40): 4nw 8 f 2GlL (in cop. with next) 27.7: (14.42): 4nw 9 m 3GlL (in cop. with previous) 27.7: (14.42): 4nw 10 f 4GlL (in cop. with next) 27.7: (14.48): 4nw 11 m 5GlL (in cop. with previous) 27.7: (14.48): 4nw 2.8: (16.10): 4nw 12 f 6GlL 27.7: (14.53): 4nw 13 m 7GlL 27.7: (15.15); 5nw 14 m 8GlL 27.7: (16.17): Mound

15 m 1NlR 30.7: (11.39): 2c 2.8: (15.39): 2w 16 m 2NlR 30.7: (12.08): 3nw 17 m 3NlR 30.7: (12.48): 4nw 30.7: (13.10): 4nw 18 m 4NlR 30.7: (12.51): 4nw 19 f 5NlR 30.7: (13.35): 4nw 30.7: (13.35): 4nw 31.7: (13.27): 4nw 2.8: (16.14): 4val. 20 m 1NlL 30.7: (13.35): 4nw 31.7: (14.36): Mound 21 m 2NlL 30.7: (14.12): Mound 31.7: (14.49): Mound 22 m 9GlL 30.7: (14.25): 4nw 31.7: (13.39): 4nw 31.7: (15.00): 4nw

23 m 1NXR 31.7: (12.04): 2br 31.7: (12.14): 2 (15m away) 2.8: (15.16): 1 24 f 2NXR 31.7: (12.19): 2br. (in cop with 3NXR) 25 m 3NXR 31.7: (12.19): 2br (in cop with 2NXR) 25A f 1NXL 31.7: (12.36): 3w 26 m 3NXL 31.7: (12.49): 3w 27 m 4NXL 31.7: (12.54): 3w 28 m 3N.R2N.R 31.7: (13.34): 4nw 29 f 4NXL4XR 31.7: (13.43): 4nw (in cop with 2NXL2NX.R) 30 m 2NXL2NX.R 31.7: (13.43): 4nw 31.7: (15.02): 4nw (apical blob on right wing) 31 m 1GXR 31.7: (14.05): 4c 32 ? 2GXR 31.7: (14.17): 4n 33 m 2NXL2NXR 31.7: (14.26): 4n 31.7: (15.02): 4nw (no apical blob on right wing) 34 m 2G.R 31.7: (14.32): 4nw 31.7: (15.04): 4nw 35 m 1G.R 31.7: (14.38): 4c For 3GlR and 2G.R (mound) See Addenda

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

No./Sex Code No. Date marked: Time: Field No. Recapture Date: Time: Field No. 36 f N.1R 2.8: (15.05): 1 37 f N.22R 2.8: (15.07): 1 38 f N.3R 2.8: (15.09): 1 39 m N.4R 2.8: (15.13): 1 40 m N.5R 2.8: (15.23): 2 41 f N.6R 2.8: (15.34): 2br 42 m N.7R 2.8: (15.49): 3nw 43 m N.8R 2.8: (16.14): 3 (in cop with 5NlR) 31.8: (13.28): 1 44 m N.9R 2.8: 16.25): 4c 45 m N.10R 2.8: (16.28): 4nw

46 m R1R 18.8: (14.51): 3nw 47 m 2RlR 18.8: (15.01): 3c 48 f 3RlR 18.8: (15.05): 3s 19.8: (12.04): 2nw 19.8: (12.05): 2nw 1.9: (16.31): 5c 49 m 4RlR 18.8: 15.09): 3sc 50 f 5RlR 18.8: (15.14): 3ec 19.8: (11.39): 2nw 51 f 6RlR 18.8: (15.24): 4nw 52 f 7RlR 18.8: (15.37): 4v 53 f 8RlR 18.8: (16.10): 5n.gate 54 f 8RlRlL 18.8: (16.15): 5n.gate 55 f 9RlR1L 18.8: (16.21): 5nw 56 f 8RlR3RlL 18.8: (16.28): 5nw 57 f R12R 18.8: (16.35): 6c 58 f 2ROR 18.8: (16.47): 6e gate 19.8: (15.29): 6c (in cop with 3ROR) 19.8: (15.30): 6 59 m 3ROR 18.8: (16.47): 6e gate (in cop with 2ROR) 60 f 5R.R 18.8: (17.10): md.

61 m BOR 19.8: (10.57): 1e 19.8: (15.49): 5c (marsh-edge cl.1) 62 f BO(R.)R 19.8: (11.07): 1n 63 m 3BO(R.)R 19.8: (11.58): 2nw 19.8: (12.16): 2nw 64 ? 4BO(R.)R 19.8: (12.09): 2nw 1.9: (16.29) 5n.cl.2 in cop with B28L 65 ? 4BOR 19.8: (12.23): 3nw 66 m 6BOR6 (black circles on rt.wing) 19.8: (12.33): 3c 11.9: (13.28): 3c wings slightly frayed 67 f 6BO(R.)R 19.8: (13.09): FC 19.8: (13.13): 4gate 19.8: (16.59): on horse dung by Field Centre drive 68 f 2BO(R.)L 19.8: (13.20): 4nw(val) 69 f 4BOL 19.8: (13.25): 4nw(val) 70 m 3BOL2BOR 19.8: (13.29): 4val 7l f 4BOL3BOR 19.8: (13.33): 4val 72 ? 4BOL4BOR 19.8: (13.35): 4ec 73 f 2B>L 19.8: (13.45): 4c. (in cop. with B>L) 74 m B>L 19.8: (13.45): 4c. (incop.with 2B>L) 75 f 3B>L 19.8: (13.52): 4wc 76 f 4B>L 19.8: (13.57): 4wc 77 f 4B>LB>R 19.8: (14.01): 4c 78 f B.>>L 19.8: (14.04): 4c 79 f 1BlR 19.8: (14.30): 7 tel.pole

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

No./Sex Code No. Date marked: Time: Field No. Recapture Date: Time: Field No. 80 ? 2BlR 19.8: (14.40): 7ne.rushbed 81 f 3B`R 19.8: (14.58): 6c 82 m 4B`R 19.8: 15.13): 6se 83 f 5B`R 19.8: (15.17): 6gate 19.8: (15.20): 6fc.gate 84 f 6B`R 19.8: (15.23): 6c 85 f 7B`R 19.8: (15.24): 6c 86 m 8B`R 19.8: (15.28): 6c 87 f B`XR 19.8: (15.55): 5n 88 f B2`XR 19.8: (15.58): 5n 89 f B3`XR 19.8: (16.01): 5n 90 f B4`XR 19.8: (16.06): 5n. 31.8: (15.26): 5 cl.1 (in cop.with B5`XR) 91 m B5`XR 19.8: (16.06): 5n (in cop.with B4`XR) 92 m B6`B.R 19.8: (16.12): 5n 93 m B`4R.R 19.8: (16.16): 5n 94 m BlXXR 19.8: (16.19): 5c 95 f B3`XXR 19.8: (16.27): 5c 31.8: (15.27): 5cl 96 f B4/XXR 19.8: (16.29): 5c 97 m BlXXXR 19.8: (16.35): 5c 98 f BllXXXR 19.8: (16.36): 5c 99 ? 2Bl.R2BXL 19.8: (16.40): 5c 100 f BXXOR 19.8: (16.43): 5c 101 f BXXOROL 19.8: (16.47): mound 19.8: (16.53): mound

102 m 1B.L 31.8: (12.58): 1 31.8: (13.00): 1. 1.9: (12.32): 1path: in cop with B1L(f) 1.9: (12.54): 1 on bracken e of path 103 m 2B.L 31.8: (13.02): 1 1.9: (13.16): 2 grassy area s.of anthill sector. In cop.with B13.RB2.L 104 m 3B.L 31.8: (13.03): 1 1.9: (12.46): 1 bracken area n.of pylon 1.9: (13.00): 1 bracken area n of pylon 105 m 4B.L 31.8: (13.06): 1 31.8: (13.16): 1 near pylon same dung patch as 100m 11.9: (12.48): 1 ne bracken by path 106 f 5B.L 31.8: (13.09): 1 107 m 6B.L 31.8: (13.10): 1 near pylon 1.9: (12.45): 1 bracken area 108 f 7B.L 31.8: (13.13): 1 near pylon; in cop 1.9: (13.02): 1 entrance from 2 but male escaped still in tandem 109 ? 8B.L 31.8: (13.20): 1 bracken 110 m 9B.L 31.8: (13.31): 1 near road fence 31.8: (13.40): 1 (bracken area) 1.9: (12.36): 1 bracken by entrance from Field 2 111 m 10B.R 31.8: (13.36): 1 bracken area 112 m 10B.L 31.8: (13.37): 1 bracken area (had 1.9: (13.26): 2 trampled bracken by Sarcophaga as prey) road fence 113 m 11B.L 31.8: (13.48): 2 bracken area 114 m 12B.L 31.8: (13.51): 2 bracken area 115 f 13B.L (very large) 31.8: (13.58): 2 bracken area 116 m 14B.L 31.8: (14.03): 2 ne corner 1.9: (12.51): 1 bracken area 1.9: (12.54): 1 bracken area

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

No./Sex Code No. Date marked: Time: Field No. Recapture Date: Time: Field No. 117 f 15B.L 31.8: (14.09): 3 sw corner 118 f 1B.R 31.8: (14.12): 3c 119 m 2B.R 31.8: (14.14): 3c 31.8: (14.17): 3c 31.8: (14.31): 3 by pylon 120 f 3B.R (very large) 31.8: (14.22): 3c 121 f 5B.R (wings frayed) 31.8: (14.26): 3c 31.8: (14.35): 3e 122 m 6B.R 31.8: (14.33): 3c 123 f 7B.R 31.8: (14.43): 4nw 1.9: (17.23): 4 valley, amid heather 124 f 8B.R 31.8: (14.47): 4val.path 1.9: (17.07): 4 valley 125 m 9B.R 31.8: 14.48): 4 by top birch 1.9: (17.09): 4 by FC gate 126 m 10B.R 31.8: (14.50): 4 heather area valley 31.8: (14.52):4 valley, heather area 31.8: (14.54): 4 valley, heather area 1.9: (17.18): 4 on ridge s.of valley towards marsh edge 1.9: (17.27): 4 FC gate area 127 f 12B.R 31.8: (14.54): 4 valley heather area 31.8: (15.16): 5 (four yds.along path from gate) 128 m 12B.R B1L 31.8: (15.02): 4c 129 m 13B.RBlL 31.8: (15.04): 4c 31.8: (15.06): 4c (next dung patch) 1.9: (13.16): 2 open grassy area at s edge of anthill sector, in cop with 2BL 130 m 15B.R 31.8: (15.10): 4c on stone 131 f 16B.R 31.8: (15.19): 5 (cl.1) 31.8: (15.37): 5 (cl.1 near gorse) 132 f 17B.R 31.8: (15.21): 5 (cl.1) 133 m 15B.R3B.L (very small) 31.8: (15.23): 5 (cl.1) 134 f 16B.R4B.L (very large) 31.8: (15.25): 5 (cl.1) 135 f 11B.R6B.L 31.8: (15.31): 5 (cl.1): in cop.with 10BXR 136 m 10B.XR (very large) 31.8: (15.31): 5 (cl.1): (in cop with 11B.RBXL 137 f 17B.R (code given in error-already 31.8: (15.37): 5 (cl.1) used above) 138 m large elongate blue blob put on R 31.8: (15.40): 5 (cl.1- on edge of wing. Incapable of flight as half left scrub above path) wing missing 139 m 12B.R6B.L 31.8: (15.43): 5 (cl.1) 140 f 12B.R7B.L 31.8: (15.47): 5 (cl.2s) 141 m 2B.1L 31.8: (15.56): 5 n 142 f 20B.L (very large) 31.8: (15.56): 5 n (rush edge) 143 m 20B.R1B.L 31.8: (15.59): 5 n. (rush edge) 1.9: (16.36): 5n, above path at end of bracken area 144 m 22B.R3B.L 31.8: (16.02): 5 by n.gate 1.9: (16.33): 5n, gorse edge 145 f 22B.R4B.L 31.8: (16.07): 7 muddy entry track 1.9: (17.19): 4 ridge s.of valley- towards marsh edge-on next dung patch downslope to male B10.R 146 m BAL 31.8: (16.09): 7 by tel.pole by fence 147 f BARBAL 31.8: 16.14): 7 rush bed edge 1.9: (14.00) 4 ridge 148 f 20B.RBAL 31.8: (16.28): 6 by bridge 149 f 20B.R5B.L 31.8: (16.26): 6 se corner 150 f 23B.R6B.L 31.8: (16.33): 6c 1.9: (16.18): 5 beside tel.pole on old cow-pat then flew onto grass. 151 m BVAR (small individual) 31.8: (16.35): 6c 152 m BAVAR 31.8: (16.36): 6c

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

No./Sex Code No. Date marked: Time: Field No. Recapture Date: Time: Field No. 153 f BAVAR 31.8: (16.41): 6c 1.9: (16.05): 6 by road fence, V midway 154 m BAVAL 31.8: (16.44): 6c 155 f BAVA.R 31.8: (16.46): 6c

156 f B.1L 1.9: (12.32): 1 (on path at entry to 1). 1.9: (13.03): 1 bracken edge (in cop.with B1.L (m) 157 m B.2L 1.9: (12.41): 1 bracken area 158 m B.3L 1.9: (12.48): 1 on soil in bracken area 1.9: (12.58): 1 3m n.of pylon between brambles, nettles, bracken etc. 159 m B4L L.wing badly frayed,R less so 1.9: (13.07): 2 bracken edge 160 ? B.5L 1.9: (13.09): 2 bracken edge 161 ? B.6L 1.9: (13.21): 2 bracken edge 162 f B.14L 1.9: (10.30): 3c (D.Paynter) 163 f B.7L 1.9: (13.32): 3 by road fence 1.9: (13.39): 3 same area 1.9: (13.02): 3 same area 1.9: (13.46): 3, same area 1.9: (14.14): 3 near road fence 164 f * B.8L * This specimen not be 1.9: (13.35) : 3 by road fence. Very included in calculations as it was sluggish, unable to fly removed from the field on the day of marking. 165 m B.9L 1.9: (13.45): 3, near road fence 1.9: (13.56): 3c (Jo). 1.9: (13.57): 3c 1.9: (14.00): 3c Kilvey Hill 11.9: (15.08): 4 Mound, by lower gorse area near fence 166 m B.10L 1.9: (13.55): 3c 167 f B.11L 1.9: (14.01): 3s-near southern edge scrub midslope 168 f B.12L 1.9: (14.08): 3n-just north of pylon 11.9: (13.49): 4 tree edge beside path from 3; very small female with extremely frayed wings 169 f B.13L 1.9: (14.09): 3n-near scrub edge

170 ? B.15L 1.9: (14.35): 3c 171 f B.16L 1.9: (14.38): 3c- 2 172 f B.18L 1.9: (14.40): 3 by road fence 173 ? B.19L 1.9: (15.48): 7 amongst Juncus by stream 174 m B.20L 1.9: (15.58): 6 downslope from gate 175 ? B.21L 1.9: (16.02): 6 30yds NNE of gate 1.9: (16.15): 6 by road fence 176 m B.22L very large 1.9: (16.09): 6 by road fence, near previous. 177 m B.23L minute one with wings frayed 1.9: (1609): 6 on same dung patch as 1.9: (16.17): 6 just by gate, beside and left hind leg missing previous path 178 m B.24L 1.9: (16.13): 6 by road fence 179 m B.25L 1.9: (16.23): 5 marsh edge 180 f B.26L 1.9: (16.25): 5 slightly upslope from last 181 f B.27L 1.9: (16.28): 5 bit further upslope 182 m B.28L 1.9: (16.30): 5n- in cop with R4.R(f)- 11.9: (13.39): 3ne, 4 yds from

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

No./Sex Code No. Date marked: Time: Field No. Recapture Date: Time: Field No. just below path midway between n.hedge, 10m nnw of tel.pole. tel.pole and gorse edge. wings not frayed but with small hole in middle of rt.wing. 183 ? B.29L 1.9: (16.45): 5cl.1, marsh edge 184 m B.30L 1.9: (16.48): 5cl.1, above middle 185 f B.31L 1.9: (16.50): 5 upslope of last

186 m B1R 10.9: (10.21): 1br 10.9: (10.22): a foot away 187 f B2R 10.9: (10.32): 2 just inside s field on upper path 188 m B3L (frayed wings) 10.9: (10.37): 2 bracken on edge of anthill part. 189 m B4L (slightly frayed) 10.9: (10.37): 2br- in net with previous but not seen initially. 190 m B5L 10.9: (10.47): 2 on dead bracken 191 m B6L 10.9: (11.07): 3ne-heather/Juncus area n.of tel.pole 192 f B7L 10.9: (11.11): 3 3m ssw of previous 193 m B8L 10.9: (11.15): 4n of gate, edge of rough 194 f B9L 10.9: (11.23): 4 valley, .n.edge 195 f B10L 10.9: (11.29): 4 s.hedge edge 196 ? B11L 10.9: (11.30): 4 4m n of previous 197 ? B12L 10.9: (11.33): 4 2 yds.n of previous 198 m B13L 10.9: (11.34): 4 2ft up-slope of 11.9: (13.56): 4 lower end of ridge previous 199 m B14L (frayed) 10.9: (11.39): 4 ridge-s.of birch 2 200 f B15L 10.9: (11.45): 4 n.end of bridge on 11.9: (13.49): 4, at entrance to 3 grassy verge 201 m B16L (slightly frayed) 10.9: (11.50): 5 by path above cl.1 202 f B17L (pristine) 10.9: (11.52): 5 near previous, e of path by gorse 203 f B17L (in error repeated code) 10.9: (12.04): 5 by tel.pole nr.n.gate 204 f B18L 10.9: (12.18): 6 by e fence 10.9: (12.23): 6 on grass c.4 m s. 205 f B19L 10.9: (12.26): 6 by fence a few yds s 206 f B20L (very small) 10.9: (12.28): 6 just by gate

207 f B.50L 11.9: (12.42): 2nw.br.edge 208 m B.51L 11.9: (12.56): 1 nr.pylon 209 f B.52L (pristine) 11.9: (12.59): 1 on grass 1m from previous 210 f B.53L (pristine) 11.9: (13.09): 2 ne.corner amongst bramble. 211 f B.54L (frayed) 11.9: (13.09): 2 on same dung patch as previous. 212 m B.55L 11.9: (13.24): 3 mid.fld. 213 m B.56L 11.9: (13.26): 3 4m from previous 214 f B.57L (wings frayed) 11.9: (13.31): 3 6m from previous 215 f B.58L 11.9: (13.36): 3nw, 4 yds wnw of tp. 11.9: (13.46): 3 n.edge by trees. e.of path [code barely visible] 216 m B60L left wing-tip missing and white 11.9: (13.41): 3 ne, 4m nearer tel.pole spot in centre than last. 217 f B61L 11.9: (13.42): 3 ne, c.1 yd downslope from previous

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

No./Sex Code No. Date marked: Time: Field No. Recapture Date: Time: Field No.

218 f N.62L 11.9: (14.06): 4 valley, w of path. 219 f N.63L (pristine) 11.9: (14.16): 5 n.end cl1, w.of path

ADDENDA (Crymlyn Bog)

308 ? 3GlR (code used in error) 31.7: (14.21): 4nw 309 m 2G.R 31.7: (14.32): md. 31.7: (15.04): 4 val.

Total (Crymlyn Bog) 222 (plus one retained)

KILVEY HILL; EASTERN SLOPES ABOVE CRYMLYN BOG SSSI K220 ? 1N.R 30.7: (14.45): D K221 m 2N.R 30.7: (14.56): D K222 m 3N.R 30.7: (15.27): D K223 ? 4N.R 30.7: (15.41): E K224 m 5N.R 30.7: (16.00): E K225 m 6N.R 30.7: (16.05): F K226 ? 7N.R 30.7: (16.10): F K227 f 8N.R 30.7: (16.16): F K228 f 9N.R 30.7: (16.20): E 31.7: (15.53): E K229 ? 10N.R 30.7: (16.22): E K230 ? 11N.R 30.7: (16.32): D

K231 m G.AR 31.7: (15.14): C K232 m G.BR 31.7: (15.30): D K233 m G.CR 31.7: (15.37): D K234 m G.DR 31.7: (15.40): D K235 m G.EER 31.7: (15.46): E K236 ? G.FR 31.7: (15.58): E K237 f G.GR 31.7: (16.01): F In cop. With G.HR K238 m G.HR 31.7: (16.01): F In cop with G.GR K239 f G.HR Code used again in error 31.7: (16.08): F K240 ? G.JR 31.7: (16.12): F K241 f G.KR 31.7: (16.16): F 31.7: (16.58): E midfield K242 m G.MR 31.7: (16.17): F K243 m G.LR 31.7: (16.20): G K244 f G.NR 31.7: (16.25): G K245 f G.OR 31.7: (16.28): G K246 m G.PR 31.7: (16.32): G K247 m G.RRR 31.7: (16.37): G K248 f G.SSR 31.7: (16.39): G K249 m G.TR 31.7: (16.46): G K250 m G.UR 31.7: (16.52): F K251 ? G.VR 31.7: (16.52): F K252 m G.WR 31.7: (16.55): F K253 ? G.YR 31.7: (17.04): F K254 ? G.ZR 31.7: (17.05): D

K255 m N1.L 2.8: (16.53): D K256 ? N22.L 2.8: (16.56): D K257 m N3.L 2.8: (17.00): D

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

No./Sex Code No. Date marked: Time: Field No. Recapture Date: Time: Field No. K258 f N4.L 2.8: (17.02): D K259 m N5.L 2.8: (17.08): E K260 m N6.L 2.8: (17.10): E K261 ? N7.77L 2.8: (17.12): E K262 f N8.L 2.8: (17.16): E K263 f N9.99L 2.8: (17.19): E K264 ? N11.L 2.8: (17.30): C K265 ? N10.L 2.8: (17.25): D

K266 f B.21L (with m.Tip.paludosa) 10.9: (12.48): C edge by ravine K267 m B.22L (frayed) 10.9: (12.55): C on grass by ravine edge K268 m B.23L 10.9: (13.01): D n.edge treeline,bordering 1a K269 f B.24L (frayed) 10.9: (13.05): D w.of tel.poles on slope K270 f B.25L 10.9: (13.12): D v.close to previous K271 f B.26L 10.9: (13.18): D grass path on steep slope s.of pylon K272 m B.27L 10.9: (13.25): D next pat up path K273 m B.28L 10.9: (13.28): D c.30yds up path- below brow of hill K274 m B.29L 10.9: (13.32): D top of grass path betw.heather beds. K275 m B.30L 10.9: (13.35): D yd. Or so from previous K276 m B.31L 10.9: (13.40): D on dung-strewn top path by fence K277 f B.32L 10.9: (13.43): D on stone 4 yds e. of previous K278 m B.33L 10.9: (13.45): D 2 yds.e of previous K279 m B.34L 10.9: (13.47): D, 2 yds e of previous K280 m B.35L 10.9: (13.52): E c.5 yds from n and e fences- fairly short grazed area K281 f B.36L 10.9: (13.58): E c.5 yds upslope of previous K282 m B.37L 10.9: (14.07): E c.1m from wood edge K283 ? B.38L 10.9: (14.10): E by old s.wall bank, mid slope K284 f B.39L 10.9: (14.13): F s.side of same wall, in rough. K285 m B.40L 10.9: (14.15): F, 1 m.from previous K286 m B.41L (frayed) 10.9: (14.17): F 1m from previous K287 m B.42L 10.9: (14.22): F nr.track over wall by bramble K288 ? B.43L 10.9: (14.25): F near previous K289 f B.44L 10.9: (14.29): F by n.edge wall K290 m B.45L (slightly frayed) 10.9: (14.32): F by wd.edge 5m from s.fence K291 m B.46L (badly frayed) 10.9: (14.36): F 4yds upslope of previous K292 ? B.47L (badly frayed) 10.9: (14.40) : F 10 yds upslope of previous, by s.fence by uppermost

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

No./Sex Code No. Date marked: Time: Field No. Recapture Date: Time: Field No. gorse. A dead Platydracus stercorarius on next pat K293 m B.48L 10.9: (14.49): G n edge of el.inst.mound K294 f B.49L 10.9: (14.53): G on path on el.inst. mound, between heather beds K295 B.50L 10.9: (15.00): G near previous,same 11.9: (15.27): F ne corner by lower ?m area track through wall line by wood edge. The code was extremely faint but first digit appeared to be 5. A male

K296 m N6R4L (frayed) 11.9: (14.46): F mid. K297 m 2N.R 11.9: (14.49): F in rough by top gore in s.fence K298 m 3N.R (v.slightly frayed) 11.9: (14.51): F 2 yds up from previous). In cop with 69f K299 f 4N.R 11.9: (14.51): F, in cop with 68m K300 m 1N.L 11.9: (14.55): F, 4 yds upslope K301 f 5N.R 11.9: (15.01): G mound, in clearing in upper gorse area. K302 m 6N.R 11.9: (15.05): G mound-slope below top gorse patch K302A .9 in black on Left wing 11.9: (15.08): G mound by lower gorse area by fence K303 f 7N.R 11.9: (15.13): G nw corner by upper 11.9: (15.13): G 1m.away. Spots wood edge faint already. K304 m 8N.R 11.9: (15.19): F nr.top gorse in fence- in rough. K305 ? 4N.L (frayed) 11.9: (15.39): F nw corner K306 f 10N.R 11.9: (15.55): D just n of top hawthorn K307 m 10N.R.L 11.9: (15.58): D just s.of same tree

Total (Kilvey Hill) 89 TOTAL (BOTH SITES) 311 (plus one retained)

BROCKWELL’S MEADOWS SSSI No./Sex Code No. Date marked Recapture Date

0 f (1) Trh 29/7 1 f (2) Trh R1 29/7 2 m (3) Trh R2 29/7 3 f (4) Trh R3 29/7 31/8 4 m (5) Trh R4 29/7 30/7 5 m (6) Trh L1 29/7 6 f (7) Trh L1 R1 29/7 30/7 7 f (8) Trh L1 R2 29/7 8 m (9) Trh L1 R3 29/7 9 f (10) Trh L1 L4 29/7 10 f (11) Trh L2 29/7 11 f (12) Trh R1 (r hind leg absent) 29/7

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

BROCKWELL’S MEADOWS SSSI No./Sex Code No. Date marked Recapture Date 12 f (13) Trh L2 R2 29/7 30/7

1 m (14) Tlh R1 30/7 2 m (15) Tlh R2 30/7 1/8 3 m (16) Tlh R3 30/7 4 f (17) Tlh R4 30/7 5 m (18) Tlh L1 30/7 6 m (19) Tlh L1 R1 30/7 7 f (20) Tlh L1 R2 30/7 8 f (21) Tlh L1 R3 30/7 9 f (22) Tlh L1 R4 30/7 10 m (23) Tlh L2 30/7 11 m (24) Tlh L2 R1 30/7 1/8

1 f (25) Td R1 1/8 2 m (26) Td R2 1/8 2/8 3 m (27) Td R3 1/8 4 f (28) Td R4 1/8 5 f (29) Td L1 1/8 6 m (30) Td L1 R1 1/8 7 m (31) Td L1 R2 1/8 2/8 8 f (32) Td L1 R3 1/8 9 m (33) Td L1 R4 1/8 2/8 10 f (34) Td L2 1/8 11 f (35) Td L2 R1 1/8 12 m (36) Td L2 R2 1/8 13 m (37) Td L2 R3 1/8 14 m (38) Td L2 R4 1/8 15 f (39) Td L3 1/8 2/8 16 m (40) Td L3 R1 1/8 2/8 17 m (41) Td L3 R2 1/8 18 f (42) Td L3 R3 1/8

1 m (43) Tp R1 31/8 2 f (44) Tp R2 31/8 3 m (45) Tp R3 31/8 1/9 4 m (46) Tp R4 31/8 5 m (47) Tp L1 31/8 6 f (48) Tp L1 R1 31/8 7 m (49) Tp L1 R2 31/8 8 f (50) Tp L1 R3 31/8 9 f (51) Tp L1 R4 31/8 10 m (52) Tp L2 31/8 1/9 11 m (53) Tp L2 R1 31/8 12 m (54) Tp L2 R2 31/8

Total (Brockwell’s Meadows) 54

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Codes for Brockwell’s Meadows:

Trh : Thorax: right humerus (blob = day-mark) Tlh : Thorax: left humerus (blob = day-mark) Td : Thorax: dorsum, central (blob = day-mark) Tp : Thorax: postnotum, central (blob = day-mark) L : Left wing (bands = units of 5) R : Right wing (bands = units of 1)

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

APPENDIX 3: SURVEY OF KILVEY HILL AND NORTHERN PARTS OF THE CRYMLYN VALLEY, GLAMORGAN

1 August 1999

The western slopes of Kilvey Hill appears highly suitable for Asilus crabroniformis. Horses permanently graze the higher flanks of the hill above St.Thomas. 1 August was a hot sunny day during a period when Asilus was flying in good numbers at Crymlyn Bog.

Ascended the hill at 13.30hrs from the car-park at the junction of Pentre-chwyth Road and Jersey Road. The path climbs steeply through conifer plantation before reaching open moorland. About 30m below the summit an ill-defined path leads down southwards to St.Thomas. Around the junction of the paths some old cow-pats lay deep in the Molinia sward and on one of these a male Asilus was seen at 13.53hrs.

Continued up to the summit, via the old Windmill Mound (W, Fig. 6) and followed the hill-top path eastwards along the southern fences of the hill-top fields. Just beyond Pen y Graig Uchaf the path leads over a rocky outcrop before a sudden descent onto a more level area of Molinia moor (pasture P, Fig. 6). Here, again about 30m below the summit, cattle and horses had been grazing and their dung littered the moor and path. A male Asilus was seen at 14.27hrs on old horse-dung on the path just before it takes a right-angled bend following the field boundary fence. From this point the ground to the right of the path has been extensively quarried and falls away very steeply, in places to Dan y Graig and Port Tennant. Cow dung was scattered along this path. Progressed eastwards and four specimens of Asilus were seen; at 14.29 (on cow-dung), 14.33 (on Nardus/Molinia turf by path), 14.35 (on cow-dung) and 14.37 (on cow-dung). This last was on the crest of the hill immediately before the path descends steeply to cross the lane from Port Tennant to Coch-y-Cwm Road, via Pen y Graig and Cae March Einon farms.

On the hill crest mentioned above, a path leads back westwards at a lower level through old revegetated quarries. Passed through the quarried section and along the lower edge of the Kilvey Hill conifer plantations, pproaching the riding school below the TV aerial on the summit of Kilvey Hill above St.Thomas. Saw a female Asilus on old cow dung at 14.55hrs. This was clearly in ovipositing mode, reversing deep into a fissure in the dung and remaining there for a minute or more before coming out and repeating the process elsewhere. The terrain hereabouts was ideal for Asilus,supporting dense clumps of bramble and bracken with grassy clearings and copious quantities of dung.

A lane leads up from the riding school to the Windmill Mound and, before the first bend on this lane, an Asilus was seen on old horse-dung at 15.03hrs. Retraced steps from the Windmill Mound down to the car-park, reaching this at 16.00 hrs.

Within a period of 2hrs 10mins, 8 Asilus were recorded and it was established that it occurs in all suitable places along the summit area of Kilvey Hill from the vicinity of St.Thomas to the Port Tennant –Pen y Graig area.

2 September 1999

Began at the Crymlyn Bog Field Centre at 13.05hrs on a warm, sunny afternoon after a dull misty morning. The temperature was in the range 21-26oC. Made a quick check in the vicinity of the gate into Field 4 to ascertain that the fly was in evidence. A single individual and a pair in cop were seen on old horse dung between the gate and the slope into the valley.

Proceeded along the road past Tir Isaf and up Coch y Cwm Road to the first gate, leading into Field B. Almost immediately on entering this improved pasture, which is separated from the reserve by a broad belt of woodland and scrub, an Asilus was seen on old cow dung between the gate and the base of the pylon. A deep wooded ravine separates this field from Fields C to G on the lower slopes of Kilvey Hill in which the mark-recapture exercise was carried out. However, horse-grazed pastures adjoin it on the western side and across Coch y Cwm Road to the north west. This latter field (Field A) was also found to be occupied by Asilus, one being seen on o cow dung close to the foot of the pylon near the centre of the field.

Returned to Coch y Cwm Road and continued up to the junction with Ty-draw Road, then along the lane to Cae March Einon (Fig. 1). Pastures along both sides of this lane appeared suitable for the species although a number of brief checks into some of the fields failed to reveal any. Where the Tir Isaf stream crosses under the lane, a field track on the right leads into very old revegetated spoil heaps from the Llanerch Slant coal mine. The floor of this site supports very rich wet heathland and shallow

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999 bog, whilst the surrounding slopes comprise mostly old revegetated colliery spoil (N, Figs. 1 and 6). The area is horse-grazed and an Asilus was seen on old horse dung on a drier part of the marshy floor. A short search of the surrounding pasture and of a large pasture on the east side of the lane (adjoining the same stream on its northern edge) failed to find further specimens, although both areas appeared ideal and were copiously strewn with horse dung.

Further south along the lane, a large field containing foundations of brick buildings and a herd of cattle similarly failed to reveal Asilus. Though mostly covered in huge beds of rush (Juncus sp), there were also numerous drier grassy areas which looked suitable, but a quick search of the cow dung in this field failed to produce any cyclorrhaphous fly larvae, possibly indicating ivermectin use by the farmer.

Beyond Pen y Graig farm the track reaches the path running along the crest of the steep, south-facing slopes of Kilvey Hill, overlooking Port Tennant and St.Thomas (Figs. 1 and 6). Followed this path westwards to the first summit, where a fence between two pastures (Fields J and K, Fig. 6) runs northwards, some 30m beyond an area of gorse. Three Asilus were seen in Field J on the track linking these fields, the first on old cow dung near the western edge of the gorse thicket, the second on bare soil very near the boundary between the fields, and the third 1-2m away on old cow dung on the track edge.

Followed the boundary fence northwards and into the next pasture (Field L) which caps the very steep, heathy, east-facing upper slope of Kilvey Hill (Field M, Fig.6) between Carn Nicholas Farm and the lane from Coch y Cwm Road to Port Tennant, via Cae March Einon and Pen y Graig farm. Very little cow dung was seen in Fields K and L, but on the steep slopes of Field M, overlooking Cae March Einon, numerous cattle tracks traversed the slopes and were copiously strewn with cow dung. This supported immense populations of Geotrupes, with many pats having three or four burrows beneath them. A single Asilus was noted on old cow dung near the southern end of this slope, close to its foot and adjacent to a tangle of gorse and bramble etc along the fence separating it from the northern end of Field J, where three Asilus had been seen earlier. The steep slope (M) was not searched further, but at its north-eastern end it is joined by very rough grazing land next to the field in which Asilus was seen on the site of Llanerch Slant coal mine, by the lane from Coch y Cwm Road past Cae March Einon. It seemed inconceivable that Asilus would not enjoy ready access across these fields, none of which are improved but which are grazed, and which consequently appeared very suitable for the species. Fields J, K and L are all clearly improved.

From the steep slope of Field M, continued westwards along the southern fence of Field L and in the westernmost corner saw a further Asilus on old cow dung amongst rank grass on a short, steeper slope. The next field westwards was clearly improved and mown except on its steep northern side which, however, showed no evidence of grazing stock. Adjoining this field is another containing rank grassland along its southern edge (Field Q, Fig.6). Here two Asilus were seen, one on old cow dung, the other close by on a stone. Crossed the improved, short-mown centre of this field over a fence into the next, which primarily comprises very rank coarse grassland in which a few ancient cow-pats were seen.

Beyond the western fence lies the cliff-top path at the eastern fence of the field immediately east of the Windmill Mound (Field O, Fig. 6). On the edge of this path, close to the field junction some 150m west of a rock outcrop, an Asilus was noted on old cow dung. Descended the rocky outcrop into the rough moorland pasture (Field P) below, where old cow-pats were seen. On one of these, amidst moorland vegetation of Molinia, Juncus squarrosus, J.effusus, Calluna etc, was another Asilus.

Returned to the cliff path at the field junction mentioned above and continued west along the southern edge of the westernmost field below the Windmill Mound. West of a fence-side bush, two further Asilus were noted; one on old cow dung and the second a metre or so away on a crow pellet. The adjacent field (Field O, Fig. 6) contained a herd of bullocks.

At Windmill Mound saw two further Asilus on old cow dung, actually on the mound itself, about 10m apart. Followed the path from here northwards along the woodland edge and along the western side of the pasture. This continues in a more-or-less northerly direction for several hundred metres before suddenly swinging sharply westwards along the upper edge of a very extensive cattle pasture to join Morris Road. Proceeded to the junction of Morris Road and the unfenced lane through this large pasture to Carn Nicholas Farm. Two Asilus seen on old cow dung on the upper (southern) edge of this pasture. At its north- eastern corner this field very closely approaches the Llanerch Slant mine where Asilus was seen previously on the old colliery spoil.

Walked up Morris Road through the pine wood, finding a female of the longhorn beetle Anoplodera rubra on a dead pine stump on the way up. Evidently there is a strong colony of this beetle breeding in this plantation. A male was found actually in the Crymlyn Bog SSSI in early August. From the television aerial (TV, Fig. 6) followed the path down to the car park at the junction of Pentre-chwyth Road and Foxhole Road.

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

During this survey a total of 15 Asilus were seen at widely spread locations all over the hill. In several areas the populations are probably considerable, although having established the presence of the fly in a given pasture no attempt was made to search for further specimens. It is most likely that a large population is centred on the south-facing slopes around the riding school above St.Thomas and up-slope to the Windmill Mound and on the adjacent moorland pasture.

5 September 1999

A hot sunny afternoon. Drove along Cefn Hengoed Road in Bon y Maen, stopping at the eastern end of Cefn Hengoed, where there is an excellent vantage point for viewing the whole valley and the SSSI. From here it was clear that whilst some of the pastures are very short-grazed there remains plenty of rough grazing on marginal lands which would appear to be suitable for Asilus, though the fields were not searched on this occasion. It was, however, apparent that Asilus could find continuous dung- strewn pastures all the way from the northern end of the SSSI and the Tir Isaf pasture to the edges of the housing estates of Winsh-Wen and Pentredwr. Furthermore, there are a number of horse-riding centres which would generate dung over large areas.

From the cross-roads at Pentredwr, drove along Crymlyn Road stopping several times to check the land on both sides. Between Glan y Wern Farm and Crymlyn Farm, the habitat continuity for Asilus is poor. Some of the Glan y Wern Farm fields look too well-kept for Asilus, but perhaps more seriously there appears to be an extensive area of dense scrub and woodland devoid of pasturing animals extending from Crymlyn Road right down to the bog itself. On the north side of the road, severances arise from residential development around Talycopa farm, woodland north and east of Crymlyn Farm and in Cwm Crymlyn, forming a break in pasturage. In any event, a search of pastures further east proved fruitless.

The extreme north-eastern end of Crymlyn Bog, between Tal y Fedw and Crymlyn Road, appears ideal for Asilus, with copious horse dung and a mosaic of unmanaged, open, short vegetation with dense tangles of bracken, bramble and gorse etc. However, despite a lengthy search no Asilus were seen.

Continued across Crymlyn Road to examine the fields belonging to Pep-twyn farm, adjoining the lane from Caer-hendy. These are improved grasslands grazed by cattle: no Asilus were seen.

Concluded from this survey that whilst the fly probably occurs as far as Pentredwr and Winsh-Wen, its dispersal further north and east is probably limited by a combination of housing developments, ungrazed scrub and woodland, arable fields, open bog and fen.

10 September 1999

Walk back along the hill-crest path to the summit of Kilvey Hill and thence down to the car-park on Pentre-chwyth Road late in the day. Ascertained by this means if there was continuous habitat occupied by Asilus extending effectively from Crymlyn Bog to St.Thomas (Fig. 6).

Left the gorse area of Field G below the electricty substation at 15.06hrs, crossing the fence just to the south of the lowest clump of gorse, to get to the upper edge of the very large Field H which flanks Dinam Road and which, at its most northerly point along that road, most closely approaches the southernmost field of Crymlyn Bog SSSI (Field 1) which is occupied by Asilus. Immediately on crossing the fence on the uppermost edge of Field H, saw an Asilus on old horse dung. This field is regularly grazed by horses, so the fly presumably occurs throughout it down to Dinam Road. The tip around the site of the derelict Tir John Power Station, and adjoining rough ground around Port Tennant (Figs. 1, 6), are also horse-grazed, indicating potential Asilus habitat in these areas also.

Adjoining Fields G and H to the west is a large pasture (Field I), which at its western end flanks the lane from Port Tennant to Coch y Cwm Road via Pen y Graig and Cae March Einon farms. This too is under regular grazing by horses and cattle, and two Asilus were seen here on old horse dung, the first at 15.15hrs in the extreme south-east corner, the other by the fence on the southern edge at 15.17hrs. The presence of Asilus in the next pasture westwards (Field J), and thence westwards along the hill- crest path, had already been established.

Continued along the hill-crest path westwards to a level area of Molinia moor at the south-eastern edge of the Kilvey Hill conifer plantations, some 30m below the Windmill Mound. At 15.37hrs, saw a female Asilus on old cow dung in an extremely

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999 rank area of Molinia and Juncus with isolated larch (Larix decidua), grey alder (Alnus incana) and small, apparently self- seeded pine (Pinus sp). Crossed this rough ground to a path leading up the slope to Pen y Graig Uchaf, just west of a rocky outcrop. Another Asilus was seen the grassy margin of the path, resting on the turf.

Entered the pasture (Field O, Fig. 6) immediately east of the Windmill Mound, where bullocks had been grazing on the previous visit. The southern edges of this field comprise very rank grassland with copious old cow pats. On one pat some yards in from the southern fence, an Asilus was perched. Crossed the fence just east of the Windmill Mound and saw another Asilus on the base of the mound itself, again on old cow dung.

Six Asilus then were seen on this occasion, demonstrating the presence of the species continuously from Crymlyn Bog SSSI along the southern summit pastures to St Thomas.

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

APPENDIX 4: SURVEY OF THE USK VALLEY, MONMOUTHSHIRE

Brecon to Llanfihangel Gobion, 29 July 1999

In 1998 a number of cattle- and horse-grazed pastures along the River Usk from Newbridge on Usk, upstream from Caerleon, to Llanwenarth below Crickhowell were visited. On this occasion the river valley was worked downstream from the Brecon area on a hot sunny day. Since Asilus was flying in good numbers at Crymlyn Bog conditions should have been optimal.

Commenced by parking in the picnic area on the western side of Brecon and walking along the river bank to Fenni-fach. This stretch of the river runs along the 140m contour for some distance, and is thus at a similar altitude to the slopes of Kilvey Hill above St Thomas, where Asilus was seen in good numbers in 1999. Only one of the five fields passed on this path along the north bank of the upper Usk was grazed by cattle, however, and this was obviously improved pasture which had been recently mown. Some of the fields on the south bank of the river looked more encouraging but the investigation concentrated on promising-looking fields on the south-facing slopes running down to the bridle-way from Brecon to Pennant, where cattle could be seen grazing the slopes.

Between the Pennant bridle-way and the line of the dismantled railway (about SO035291: Fig. 7A) the slopes lying eastwards for several hundred metres looked very promising. These supported herb-rich pasture with numerous large anthills (Lasius flavus), very similar to the anthill sections of Fields 2 and 5 at Crymlyn Bog, and implying some antiquity. Moreover, there were large quantities of cow dung in which muscid larvae were numerous. However, half an hour’s searching failed to reveal any Asilus.

The valley floor and lower slopes downstream between Brecon and Llansantffraed also looked promising, but the pastures appeared to be grazed solely by large flocks of sheep. At the roadside picnic site below Llansantffraed (Fig. 7B), the slopes immediately above the site were noted to be occupied by horses and cattle, with a footpath leading up the hill through the pastures. Took the path in a north-westerly direction towards a wooded slope which runs towards Allt yr Esgair. Beyond the first two improved pastures, the next (at about SO129228) looked very suitable, being rank, herb-rich, unimproved grassland with small thickets of brambles and large oaks amongst which the cattle and horses were grazing. Again the dung was rich in muscid larvae but no Asilus could be seen during a half-hour search. The altitude here was around 200m and comparable to the altitude of the summit of Kilvey Hill: this may be around the maximum for Asilus in South Wales.

Although not on the Usk itself but on a major tributary, the Rhiangoll, the large flood-plain between Felindre and Tretower was investigated. This comprises pasture and arable enclosures, butwith some suitable-looking cow-pastures along the very narrow road and skirting the stream on the south side of Felindre village, where it was possible to park (Fig. 7C). The hedgerows here (SO178228) were obviously of considerable age, containing some very large old oaks and field maple (Acer campestre) of a remarkable size and comparable to the largest on Bredon Hill. The cow dung here supported a good insect fauna which augered well for Asilus, but again none were seen. The altitude here is about 110m.

Rejoined the A40(T) above Crickhowell and stopped downstream from the Llanwenarth Arms Hotel, where the river swings southwards away from the roadside, and the uppermost of several large pastures begins (Fig. 7D). Two of the pastures between Maerdy Farm and Llanwenarth church were examined in 1998 without finding Asilus. Like them, the pasture at SO259159, which is at altitude of about 70m, was semi-improved and looked suitable for Asilus but none were seen here either, despite an abundance of insect-rich cow-pats.

Next surveyed the pastures at Llanfihangel Gobion, where previous surveys had indicated suitability for Asilus. A much more extensive search was carried out than on former visits. The area worked covered the very large area of floodplain above Pant- y-Goitre Bridge between the Usk Valley Walk and the river itself, and including the impressive oxbows - in all a very large area of unimproved pasture (Fig. 7E). Despite optimum conditions and copious fly-rich cow dung, no specimens of Asilus were seen after some two hours of searching.

A final visit was made to the riverside pasture at Clytha where the fly had been seen in 1998 (Fig. 7F), but again, after upwards of one hour’s search, none were seen on this occasion.

CCW Contract Science Report No. 525: July 2002 The Autecology of the Hornet Robberfly Asilus crabroniformis L. in Wales, 1997-1999

Newbridge on Usk to Llanfihangel Gobion, 5 September 1999

Left Swansea on a very dull, cloudy and misty morning with the fields covered by very heavy dewfall. By 11.00am, however, it was a sunny morning. Arrived at the car-park on the A449(T) by the Motte and Bailey below Newbridge on Usk (Fig. 7G). The objective was to search the riverside pastures from below the Motte and Bailey itself (ST 389940) to the junction of the minor roads (at ST 395992).

The lower, very large pasture occupying the southern half of this area appeared perfect for Asilus, being for the most part dominated by rank grass, nettle, thistles, ragwort etc, and with a drier slope on it eastern flanks in which herb-rich grassland was interspersed with bramble thickets. The field was occupied by a herd of cattle, and dung of all ages was copiously strewn about attended by large numbers of the flies Scathophaga stercoraria and Microchrysa polita, and the stercoricolous muscids Musca autumnalis, Polietes lardaria, Morellia sp, Neomyia sp and Mesembrina meridiana, all busily active in the hot sunshine. The dung appeared to be in a healthy state, supporting larvae of these same flies. Wondered if the absence of Asilus was due to their not having left their roosting quarters, but on subsequent evidence from Crymlyn Bog, suspect that this was unlikely to be the explanation.

During the 1998 survey, one of the other pastures in this group was visited, namely that just downstream from the bridge at Newbridge on Usk, on the east bank, which borders along its southern edge the large pasture mentioned above. This pasture appears to be much more improved, lacking rank vegetation and the drier slopes, although the same flies were here attending the cow dung,and the same species were present in good numbers in their larval stages.

Pastures downstream from the Motte and Bailey (referred to above) and those to the east of the A449(T) from Cat’s Ash to Bertholey House appeared to be occupied by sheep, and are thus probably unsuitable for Asilus.

Intending to examine the pastures by the Olway Brook between Gwernesney and Llanishen Court, it was found on arrival that there was a large agricultural show in preparation with much resultant activity. Instead took the minor road over the motorway past Cefntilla Court, stopping at about SO 409035. From here, surveyed the local pastures on both sides of the road. Those to the west, in the Cefntilla Estate, at least as far as the first valley traversed by the footpath, were improved pasture grazed by sheep, and therefore probably unsuitable. Of those to the east of the road, one was occupied by a herd of cattle but was improved: investigation yielded no Asilus. Moreover, the view across the valley of the Olway Brook from this vantage point revealed the preponderance of sheep-farming in this area.

Continued via Gwehelog hoping to locate some unimproved pastures near Bettws Newydd which were marked on the Phase 1 survey map supplied by CCW. Stopped about midway whilst descending the valley to Llancayo and took the opportunity to examine pastures adjoining this road, finding them to comprise ideal Asilus habitat of mostly very rough pasture with margins of brambles etc, and copious quantities of fly-rich cow-dung. Again however, despite optimum weather conditions, no Asilus could be found.

Proceeded via the Chain Bridge and Bettws Newydd to the area of Coed y Bwnydd and Clytha Hill, in which unimproved pastures were indicated on the Phase 1 map. After some perambulation of the vicinity, however, no suitable habitat was located. Continued to the riverside car-park at Clytha, where a single Asilus had been seen in the large riverside pasture in 1998. In the 1998 survey report (Clements, Skidmore & Denton, 1999) it was suggested that a colony may be centred on the pastures between the alluvial one in which the fly had been seen and the road from Bettws Newydd to Clytha. These were duly examined (Fig. 7F) and again included ideal Asilus habitat, with some excellent unimproved woodland and shrub pasture. The usual stercoricolous fly fauna noted earlier was again present, and the dung was rich in muscid larvae, but no Asilus were found.

Finally visited the area upstream from the bridge at Pant y Goitre, by Llanfihangel Gobion (Fig. 7E). After a prolonged search covering the oxbow area which was previously examined on 29 July, no Asilus were found.

CCW Contract Science Report No. 525: July 2002