Provided by the author(s) and University College Dublin Library in accordance with publisher policies. Please cite the published version when available.

Title The fauna (Coleoptera) from the Neolithic trackways Corlea 9 and 10: the environmental implications

Authors(s) Reilly, Eileen

Publication date 1996

Publication information Raferty, B. (eds.). Trackway Excavations in the Mountdillon Bogs, Co. Longford, 1985-1991 (Transactions of the Irish Archaeological Wetland Unit 3)

Publisher Irish Archaeological Wetland Unit

Item record/more information http://hdl.handle.net/10197/5552

Downloaded 2021-09-23T18:29:14Z

The UCD community has made this article openly available. Please share how this access benefits you. Your story matters! (@ucd_oa)

© Some rights reserved. For more information, please see the item record link above. Extract from:

Raftery, B. 1996. Trackway Excavations in the Mountdillon Bogs, Co. Longford, 1985–1991. Transactions of the Irish Archaeological Wetland Unit 3. Crannóg Publications, Dublin. TRANSACTIONS VOLUME THREE

13 THE INSECT FAUNA (COLEOPTERA) FROM THE NEOLITHIC TRACKWAYS CORLEA 9 AND 10: THE ENVIRONMENTAL IMPLICATIONS.

Eileen Reilly

INTRODUCTION Tottenham 1954; Pearce 1957; Lindroth 1974, 1985; Harde 1984; Friday 1986; Hansen 1987; Morris 1990) This report looks at 9 samples from Corlea Bog, and the British Comparative Collection of in Trackway 9 and one sample from Corlea 10. This the Natural History Museum, London (with some site dates to the Neolithic and is the oldest trackway help from Dr. Peter Hammond). The species list known from this particular complex of sites (Raftery appears in Table 1 and is in taxonomic order follow- 1990). The samples were taken in 1989 by Brenda ing Kloet & Hincks (1977). All samples produced Collins at the time of the original excavation and all insect remains but the richness of particular samples came from the layer immediately above the track- compared to others is shown in Figure 507 and the way. It was hoped that the insect remains found percentage variation of species per sample is would give an insight into the environment of the described in Figure 508. site at the time, the plant community and also com- plement the archaeological information, particularly RESULTS in terms of the types of wood used in the construc- tion of the trackway. A range of sites in Britain simi- Environmental Reconstruction lar to Corlea have been looked at in this way Using the habitat requirements for every (though not all date back to the Neolithic), but, species of , their dominance and adaptability, apart from one preliminary report from Derryville it is possible to reconstruct the dominant environ- Bog, Co. Tipperary (Reilly, unpublished), which mental and ecological factors of the site at the time shows a similar suite of , no previous work of their deposition. Care must be taken not to on these types of sites has been carried out in assume too much from their modern habitat Ireland. Comparisons will, therefore, be made with requirements (Kenward 1975) which is why fossil British sites, but, the drawbacks and limitations of records are an important resource. The finds from such comparisons must be taken into account and sample C10 were very poor and in general it is con- will be discussed below. sidered wise to view the samples as a whole as the exact relationship/location of the samples is not THE SAMPLES: RECOVERY OF BEETLE known. As these samples were not taken in mono- REMAINS lith form (see Girling 1985 etc.) they serve as a snap- shot of a particular point in time. The relative stabil- The samples ranged in size from 1-8kg and were ity of the environment portrayed cannot be taken from between the timbers on the surface of the assessed. However, further studies in this area trackway. Two sub-samples from sample 1a were could establish this. Of the species found only 2 processed by Ms. Collins and are listed as 1i and 1ii (possibly 3) are dependent on wood, one of which is respectively in the species list. All the samples were very rare today, some others are found commonly processed according to the now familiar paraffin in forest habitats but by far the majority are indica- floatation method as devised by Osborne & Coope tive of aquatic conditions and bogland dominated (1968). The samples were disaggregated using hot by Sphagnum, Carex spp. (sedges) and Phragmites water and washed over a 300 micron sieve. The (reeds) but also areas of possible drier bogland with retent in the sieve was then treated with paraffin Calluna (ling) and Erica sp. (heather) indicated. and cold water added. The paraffin concentrates the insects by adhering to the waxy cuticle of the insect Aquatic element exoskeleton. The flot was then poured through a 300 The aquatic element of the samples is prob- micron sieve, washed with detergent in hot water to ably the single largest grouping with both strict remove the excess paraffin and stored in alcohol. All water species and pond-side, aquatic species being residues (which were very large) were kept. The represented. Agabus affinis and A. chalconatus occur beetles were then separated from the plant material in stagnant acid pools while both Hydraena riparia by sorting in alcohol using a low-powered binocular and Ochthebius minimus occur in stagnant and run- microscope and were identified using the familiar ning water. Coelostoma orbiculare and Laccophilus sp. range of keys and reference material (Joy 1932; also occur in shallow stagnant water, although the

403 IRISH ARCHAEOLOGICAL WETLAND UNIT

GENUS/SPECIES 1i1ii1a1b2a2b3 4C10

CARABIDAE Nebria brevicollis (F.) - - - 1 ----- Elaphrus cupreus Duft. -1--1---- Bembidion lampros ? (Hbst.) - - - 1 1 ---- B. properans Steph. -----1--- Pterostichus diligens (Strm.) 1 - 11141- - P. nigrita (Payk.) - 1222211- P. anthracinus ? (Panz.) - ----1-2- P. gracilis (Dej.) - - 1 - - 4 - 1 - P. minor (Gyll.) - - - 1 2 - - 3 - Pterostichus sp. --2----3- Agonum nigrum Dej. -----1-2- A. micans Nic. ---1----- A. piceum ? (L.) - ----1--- A. gracile Strm. -1--2-1?1- A. assimile (Payk.) 2 - - 2 ----- A. albipes (Payk.) - - - 1 ----- A. obscurum (Hbst.) - ----1--- Agonum sp. ---1----1 Carabidae sp. indet. - - 3 - 1 4 - - - DYSTICIDAE Laccophilus sp. --12-142- Agabus chalconatus (Panz.) - - - 1 ----- A. affinis (Payk.) ------1-- Agabus sp. - 1 1 1 - - 2 - - Ilybius sp ---1-11-- HYDROPHILIDAE Coelostoma orbiculare (F.) - - 6533-7- Sphaeridium scaraboides ? (L.) ------1- Cercyon tristis ? (Ill.) 1 ------1- C. sternalis Sharp -2-1?1---- Cercyon spp. (immature) - - - 2 - - 1 3 1 Megasternum obscurum (Marsh.) - ----1-1- Cryptopleurum minutum (F.) - ----31-- C. crenatum (Kug.) - ----1--- Cymbiodyta marginella (F.) 3 3 ------Chaetarthria seminulum (Hbst.) 1 - 4431-3- HYDRAENIDAE Hydraena riparia Kug. -1112122- Ochthebius minimus (F.) - - - 1 - 1 3 1 - Ochthebius sp. 11-----2- STAPHYLINIDAE Phylodrepa sp. - - - 1 - 1 - - - Acidota crenata (F.) - - - 2 ----- Lesteva punctata Er. 114-2--4- L. heeri (Fauv.) - 3 3 7 - 3 2 3 - Stenus juno (Payk.) ------1- Stenus spp. 1 24978510- Lathrobium multipunctatum Grav. ---1---1?-

Table 1, Part A. Species list from Corlea 9 (C10 = Corlea 10) according to Kloet & Hincks (1977).

404 TRANSACTIONS VOLUME THREE

GENUS/SPECIES 1i1ii1a1b2a2b3 4C10

STAPHYLINIDAE Cont. L. terminatum Grav. --3112-1- L. elongatum ? (L.) ------2- L. brunnipes (F.) - - - - 2 ---- L. fuvulum ? Steph. - - - 2 - 5 - 1 - Lathrobium sp. --2------Erichsonius cinerescens (Grav.) - - - 2 - 2 - - - Philonthus nigrita (Grav.) - - - - 1 ---- Philonthus spp. - - - - 1 - 1 - - Staphilinus erythropterus (L.) - ----1--- Staphilinus sp. --1------Staphilinus/Philonthus sp. - - - 5 ----- Quedius boops (Grav.) ------1- Quedius sp. - - 1 - - 1 - - - Quedius/Philonthus sp. - ----432- Tachyporus sp ------1- Aleocharinae gen. et. sp. indet. - - 3 - 2 1 - 1 - PSELAPHIDAE Bryaxis bulbifer (Reich.) ------2- Bryaxis sp. - 1 1 2 ----- Reichenbachia juncorum (Leach) - - - - 1 3 - 1 - R. (Trissemus) impressa (Panz.) - - 1 2 - 3 - 2 - SCARABIDAE Aphodius ater (Deg.) - - - - 2 ---- Aphodius sp. --1----1- ELATERIDAE sp. indet. ? - 1 ------NITILDULIDAE Omosita/Epuraea sp. ? (immature) 2 - - 1 - 2 - 6 - CORYLOPHIDAE Corylophus cassidoides (Marsh.) 1 1 - 1 - 3 - - - ANOBIDAE Anobium sp. - -1------CHRYSOMELIDAE Plateumaris discolor (Panz.) 2 144814445 APIONIDAE Apion poss. seniculus Kirby - 1 ------Apion spp. - - 2213-3- Strophosoma sp. -----1-1?- Eremotes ater (L.) (= R. chloropus) ---111--- Limnobaris pilistrata/t-album (L.) - 1 1 - 1211- ericae (Gyll.) ------1 Ceutorynchus sp. ------1- Curculionidae sp. indet. - - 1 - 1 ----

Table 1, Part B. Species list from Corlea 9 (C10 = Corlea 10) according to Kloet & Hincks (1977).

405 IRISH ARCHAEOLOGICAL WETLAND UNIT

25 50 47

43 21 40 19.7 20 40

16.7 30.5 15 30 28.4 12.6 11.5 21 Percentage 10 Percentage 20 18 8.3

11.6 5 5 3.7 10

2 4.2

0 0 1i 1ii 1a 1b 2a 2b 3 4 C10 1i 1ii 1a 1b 2a 2b 3 4 C10 Sample Number Sample Number Figure 507. Sample productivity of beetles (as % of Figure 508. Species variation per sample (total number the total number of individuals, 436). of species, 95). former also occurs in pond detritus. Cymbiodyta mar- ing Stenus juno are found in moss, on mud around ginella occur in shallow ponds or pools with vegeta- ponds and generally in plant litter in wet areas. Both tion. Lesteva species present are found in mosses in The plant species associated with wet bog- damp places as are the pselaphids Reichenbachia land and fenland are indicated by a huge variety of impressa, R. juncorum and Bryaxis bulbifer which is different species who both live on them, at their also found in Phragmites litter. Corylophus cassidoides roots or are predacious on other insects who live in is also found in Phragmites litter. this environment. Of the Carabidae present Plateumaris discolor, generally the most com- Pterostichus nigrita is common in Sphagnum and also mon species found in the samples, feeds on in banks of Carex spp., as are P. minor, P. gracilis and Eriophrum (cotton grass) and among Sphagnum, its P. anthracinus. Elaphrus cupreus is found at the mar- larvae common on the roots of the same plant. The gins of all kinds of shallow water but also in marshy species of Limnobaris found appears to be L. t-album forests, which will be discussed also. Of the rather than L. pilistrata, however, L. t-album has never Agonum species present, Agonum gracile is common been found in fossil situations (Dinnin and Skidmore in wholly wet, vegetation rich places in the immedi- 1995) and so the likelihood is that it is L. pilistrata. It is ate vicinity of stagnant water, also on Sphagnum and a common feeder on various Cyperaceae and Carex spp. A. piceum is found on Carex and Equisetum Juncus spp. (rushes), also on Phragmites. (Horsetail) while A. micans is found in muddy places Of the drier bogland species, the weevil and on river banks were vegetation is sparse. Micrelus ericae occurs in C 10 which feeds on Calluna A. nigrum is common among Carex and Phragmites (heather) and Erica sp. Philonthus nigrita is common and A. albipes occurs in shaded mosses. Chaetarthria among Calluna while two species of Strophosoma seminulum occurs in Sphagnum but also occurs under (exact species unknown in these samples as only a debris beside stagnant water. A great number of the head and fragments of elytra were found) are taken Staphylinidae species present are common in on Calluna and Erica, one species Strophosoma sus is Sphagnum and the accumulated wet litter associated known as the ‘heather weevil’. with Carex, Phragmites and Juncus spp. (rushes). Apion spp. occur on a wide variety of herbs These include all of the Lathrobium species present with Apion seniculus common on buttercup and med- with the possible exception of L. fuvulum. A number dick, species associated with meadows. of these species and Erichsonius cinerescens have been Ceutorynchus sp. occur on Crucifereae (the Cabbage taken from moorhen’s nests and this is of course family) which includes dry land species but also wet- another possibility in this environment. Acidota cre- land species such as water-cress. These taken togeth- nata is found in moss while most Stenus spp. includ- er may indicate the presence of drier land nearby.

406 TRANSACTIONS VOLUME THREE

Foul element tree fungi/bark. Quedius boops prefers drier ground This element will include some of the but is common in birch scrub. Strophosoma sp. which species previously mentioned. However, a number was discussed above has two species which are of species occur in fouler conditions, often on dung commonly found attacking birch and oak (S. capita- and will therefore be treated separately. Both tus) and also hazel and beech (S melanogramma). As Cercyon sternalis and C. tristis are found in decaying all these species of trees were used in the construc- plant matter, often in marshes and on riverbanks tion of the trackway (I.A.W.U. 1993) it is possible and pond sides. that either of these species may have occurred. L. elongatum and Bryaxis bulbifer, mentioned The most interesting species present is before, are common in decaying reed refuse in fen Eremotes ater which today is very rare. It is currently and marsh situations. found only in Sherwood Forest, Nottinghamshire Of the species commonly found in dung, and Scotland but its fossil records of Thorne Moor Aphodius ater is common in the droppings of both (Buckland 1979), Somerset (Girling 1979) and domestic and game but can also be found in Hampstead Heath (Girling and Grieg 1977) show decaying plant matter and prefers exposed habitats. that it was once more widespread. It is found in Cryptopleurum minutum and C. crenatum are found dead stumps of coniferous trees particularly pine, in dung, but both are also associated with but also in oak and beech. It is tempting to suggest decaying plant debris/organic matter particularly in that its more northerly range means that tempera- marshland and damp places. Megasternum obscurum tures at the time were slightly colder than today. is associated with rotting vegetable matter and in However, it is far more likely that its current restric- wet moss, while Sphaeridium scaraboides is common tions have more to do with widespread forest clear- in herbivore dung. It is not clear if the dung species ance from the Bronze Age onwards (climatic factors actually show the presence of herbivores crossing will be discussed again later). From the studies done the trackways or if they are casualties (i.e. drowning of tree types used in construction pine does not fea- in the bog, see Dinnin and Skidmore 1995) from ture in the survey of Co. Longford, although yew is nearby drier upland where herbivores or indeed present. However, pollen diagrams from Co. Louth game animals are grazing. (Weir 1995) show that in the Neolithic, Pinus sylvestris (Scots pine) was present though not in Woodland element This includes not only species which are exclusively tree feeders (both dead wood and liv- 60 ing) but also species which prefer forested habitats, including fungus feeders or the degree of shade afforded by stands of trees. On the ground, a num- 50 ber of species of Pterostichus including P. gracilis are often found under bark but in particular P. diligens 40 is common in shaded Sphagnum bogs with alder, birch and Vaccinium (cranberry, billberry), common- ly known as ‘carr woodland’. Nebria brevicollis is 30

found under bark and in litter but is a pronounced Percentage inhabitant of deciduous forest (Lindroth 1974). It is also found under moss and bark of tree stumps 20 where it is predacious on Collembola and mites. Agonum obscurum is a species which requires shade 10 and is found in swampy deciduous woods, particu- larly in hazel and ash stands in such forest swamps but also under alder. A. assimile is common under 0 bark and large numbers can be seen under moss Aq. Wet. Env. Wood Phy. D/F and beneath loose bark on shaded forest soils. Habitat Groupings A. albipes will often be seen with it (Eyre and Luff Aq. = Aquatics, 1990). Phylodrepa sp. seems to occur mostly in flow- Wet. Env. = Wetland Environment ering shrubs, nests, burrows, mouldy plant debris Wood = Wood and woodland indicators Phy. = Phytophagus species (plant feeders) and rotten tree trunks and in tree fungi. D/F = Dung/foul species Omosita/Epuraea sp. is difficult to place as Omosita species are commonly found on dry carrion while Figure 509. Percentage of individuals occurring in each Epuraea spp. are common in flowers, sap and in habitat group.

407 IRISH ARCHAEOLOGICAL WETLAND UNIT large numbers. It may be that pine, although pre- Eremotes ater and Strophosoma melanogramma occur sent, was not used for construction purposes and on rotting oak and pine. The evidence pointed to a that E. ater was, therefore, attacking the deciduous deciduous woodland with a freshwater fen sub- species present particularly oak. A graph showing strate at the site. These species had all reached the the different habitat groupings described above is wetlands of the Irish midlands by the Neolithic but presented in Figure 509, with further refinements. samples from earlier deposits would be needed to establish if they were in Ireland at an earlier date. DISCUSSION An interesting omission from the samples was a large number of Anobidae, with only one Environment of the trackway possible fragment occurring. With large timber The information from the beetle remains trackways, such as were found at Corlea 9, it is found points to small pools of acid water (Agabus interesting that at least Anobium punctatum (the affinis, A. chalconatus, Ochthebius sp. etc.) surrounded woodworm beetle) should not have occurred in by the accompanying range of wetland plant species greater numbers. The same anomaly was noted by - Carex spp., Juncus sp., Phragmites, Eriophrum, Robinson at Flag Fen (1991) while samples from the Calluna and Erica indicated by the plant feeder Iron Age settlement at Meare Lake in Somerset Plateumaris discolor, and the weevils Micrelus ericae (Girling 1979) produced large numbers of Anobium and Limnobaris pilistrata/t-album. This is a fairly typi- punctatum. Low values were also noted from the cal picture of a raised bog with the accompanying Neolithic samples at Runnymede Bridge (Robinson range of beetles which can exploit such terrain espe- 1991). This led Robinson to the conclusion that the cially the decaying vegetation associated with it. timbers at Flag Fen and Runnymede must have Sites in Britain from the Neolithic to the Iron Age become waterlogged quite quickly after being laid with similar structures show a similar suite of down, before infestation by large numbers of wood- insects. The Sweet Track in Somerset (Girling 1984), boring beetles. He notes that wood-boring beetles while having much more variety in terms of species, were absent from the trackway timbers of the has a similar range and indicated a swampy Somerset Levels except where infestation had eutrophic fen with locally growing carr woodland. occurred before the timbers were laid down (Girling Much larger tracts of water than are likely to have 1979). This could have been the case at Corlea 9 been present at Corlea 9 are indicated by the larger were reasonable numbers of Dysticidae, number and variety of water species present at this Hydraenidae and Hydrophilidae attest to wet con- site and other later Bronze Age sites such as Thorne ditions. However, examination of samples of the Moor (Buckland 1979) and the ‘Briggs Raft’ site wood itself would probably be the most useful way (Buckland 1981). This was particularly the case at of confirming this hypothesis. the latter site, where the species present showed the brackish fen environment of this part of the Humber The Neolithic Climate Estuary during the Late Bronze Age. Many studies from similar sites in Britain Some species occur in these samples which have produced evidence of temperature that was do not appear from fossil lists on other sites, espe- slightly higher than today’s, particularly summer cially Reichenbachia impressa. This did occur on temperatures, and a pronounced continentality. Of Thorne Moor (= Trissemus impressa) but is not pre- the rarer species coming from the samples only sent from any of the Somerset Level sites. The rea- Eremotes ater would appear to be extinct from Ireland sons for this are not clear and would require further and this is probably as much to do with forest clear- work. While we know what species now occur in ance than any change in temperature. However, Ireland it is still not possible to say how early they studies from other sites particularly the Sweet Track arrived and, apart from those known to have disap- (Girling 1984) showed that a) the present geographi- peared over the last 200 years, which species have cal range of species no longer found in Britain and b) become extinct further back in history. A rare look the combined distribution of the northern limits of at a Mesolithic species list from Westward Ho!, the most thermophilous species pointed to possible Devon (Girling and Robinson 1987) shows many of mean January and July temperature of 2˚C and 18˚C the same species of beetle which occur 2000 years respectively, some 2 degrees colder in winter and later at Corlea. Here the site consisted of a ‘drowned warmer in summer than the 1984 temperatures for forest’ and the water species including Agabus affinis southwest England. At this site the study was indicated peaty pools of stagnant water. Lesteva heeri restricted to ground beetles whose ranges are more which occurs by ponds, in willow swamps and in likely to be restricted by climate. A survey showed marshes was also well represented. Plateumaris dis- that more than half of the beetles occurred below the color occurs feeding on Eriophrum and Carex while 15˚C July isotherm and that there was a distinct

408 TRANSACTIONS VOLUME THREE avoidance of the western coast of Norway which Although some dung feeders are present was subject to a more oceanic climate. These findings there are very few indicators for the presence of should have some implications for the Irish fauna. humans (markedly synanthropic species) and the Was the temperature in Ireland different to that of assumed archaeological sites nearby. However, sites southern Britain or did the tendency towards conti- that have been excavated in this type of environ- nentality apply to Ireland also? Research by ment e.g. Clonfinlough, Co. Offaly (I.A.W.U. 1993) Buckland at Thorne Moor, S. Yorkshire (1979) would would be a useful comparison and would provide appear to show the same results as at the Sweet information on the domestic assemblages of sites in Track with a change towards a more oceanic regime this environment. occurring much later in the Bronze Age. While we Finally, changes in the environment of the know that a combination of forest clearance and an sites could be inferred by comparisons with later increase in rainfall led to the inception of blanket sites or by a monolith being taken through the peat, bogs in the west of Ireland, variations in temperature preferably incorporating a number of sites crossing are harder to recognise and the contraction and each other. This has worked well in Britain and pro- expansion of certain thermophilous beetles could be vides not just a snapshot, but a continuous picture a useful tool in further studies. through time of the changing environment of the sites and the wider locality. SUMMARY AND FINAL REMARKS ACKNOWLEDGEMENTS With the number of trackways found so far by the I.A.W.U. well into its second thousand, the potential I would like to acknowledge the help and assistance for a comprehensive study of the wetland and of the following people: woodland environment of the Midlands during the John Tierney, Martha Hannon and Mags McCarthy Neolithic, Bronze Age and Iron Age is immense. of the Archaeological Services Unit, U.C.C. Dr. Peter While the beetles here clearly indicate the raised Hammond and Ms. Sharon Shute, Department of bogland environment surrounding the trackway the Entomology, Natural History Museum, London. range of wood-borers and feeders is disappointing Dr. Paul Buckland, Department of Archaeology and and does not give the picture of the ‘Old Forest’ Prehistory, University of Sheffield. Prof. Barry fauna that was hoped for. This is probably more of a Raftery, Department of Archaeology, U.C.D. Mark reflection on the location of the samples taken and Brennan, Berkeley Library, Trinity College Dublin. ‘interference’ from the peat level above the track- Suzanne Dickenson, Paul Daly, Eanna O’Brien, way that grew when it went out of use then it is on Abina Reilly for various forms of support, assis- the actual range of species present in Ireland at this tance and the use of computers! And finally, to time. Actual samples of wood should be removed Rónán for editorial assistance, love and support. and looked at (see Buckland 1979; Girling 1976- Thank you one and all! 1985) as well as samples from within the sub-struc- ture of the trackways.

409 IRISH ARCHAEOLOGICAL WETLAND UNIT

410