The Rove Beetles of Leicestershire and Rutland
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LEICESTERSHIRE ENTOMOLOGICAL SOCIETY The Rove Beetles (Staphylinidae) of Leicestershire and Rutland Part 1: Sub-families Paederinae, Pseudopsinae and Staphylininae Derek A. Lott Creophilus maxillosus (Graham Calow) LESOPS 24 (2011) ISSN 0957 – 1019 Correspondence: 5 Welland Road, Barrow upon Soar, LE12 8NA VC55 Staphylinids Part 1 2 Introduction With over 56,000 described species in the world, the Staphylinidae are the largest family in the animal kingdom (Grebennikov & Newton, 2009). Around a quarter of the British beetles are rove beetles, so they represent an important component of biodiversity in Britain. However, because of perceived difficulties in their identification, they have not received the attention that they merit. This paper aims to play a part in redressing that imbalance by listing all reliable records from Leicestershire and Rutland for the different species and analysing which species have declined locally over 100 years of recording rove beetles and which have prospered. The subfamilies treated in this first part include the largest and most conspicuous species in the family. The geographical area covered is the vice county of Leicestershire and Rutland (VC55). Some records from adjacent banks of the River Soar that technically lie in Nottinghamshire are also included. These records can be distinguished by the use of Nottinghamshire parish names. Identification Staphylinidae can be easily recognised among beetles in the field by their short wing cases that leave five or six segments of the abdomen exposed and flexible. In fact they look more like earwigs than other beetles. For identification to species, all the members of the subfamilies in this part will be covered by the forthcoming Royal Entomological Society handbook to Staphylinidae parts 6 and 7 due for publication in 2011. Food All the species covered in this part are believed to be predators both as adults and larvae, but scavenging dead animal material undoubtedly plays a part in the diet of many species as well as capturing live prey (Good & Giller, 1991). Typical prey items include other insect larvae, springtails and mites. Injured animals will always be attacked in preference to healthy victims and in these instances the prey spectrum is undoubtedly wider. The front legs of the adults have long movable coxae and trochanters. Betz & Mumm (2001) described how these are used to trap and hold prey by the species Philonthus marginatus . Adhesive setae on the front tarsi are also used to immobilise prey. Many species in the genus Quedius have large eyes equipped for diurnal hunting. They will eat other Staphylinidae if they are put in the same tube . Habitats Rove beetles can be classified into two groups according to their habitats. The first group is found in small patches of habitat with dense concentrations of prey. These habitats include • dung, • carrion, • rotting fungi, • nests of mammals, birds and social Hymenoptera either underground or in tree hollows, • artificial litter piles such as compost heaps and dung heaps, • various habitats associated with wood decay. The second group is found in more extensive habitats with lower concentrations of prey and consequently sparser density of rove beetle populations. Soil humidity and temperature are important factors in determining occupancy of these more extensive habitats, because this is where the larvae develop. These factors are in turn determined by natural disturbance cycles caused by, for example, grazing or flooding. Wetland species can be grouped into permanent wet mire species that require the soil to be waterlogged all year round and fluctuating marsh species that occupy sites, where soils dry out to varying extents in the summer. VC55 contains some important sites for rare species that occupy undisturbed fluctuating marsh with soils remaining humid in the summer (Lott, 2009a). In fact, Saddington Reservoir is designated as a Site of Special Scientific Interest largely because of this type of rove beetle community that is present there. Riparian species are dependent on deposition of fresh sediment by rivers during Floods. The larvae develop in these sedimentary deposits when they become exposed by falling water levels in the spring and summer. VC55 Staphylinids Part 1 3 Sources of records Most of the records listed in the systematic section are based on species identifications by the author. A small number of additional records that are considered to be reliable are listed separately under each species. Species, whose inclusion in the Leicestershire and Rutland list is due to unreliable records in the literature, are listed separately. Three main sources of records were used. Manuscripts and literature - Lott (2009b) described the history of beetle collecting in VC55 and the progression of literature and manuscripts that it generated. It is evident that the first wave of collectors, including Henry Walter Bates and Francis Plant, largely ignored the Staphylinidae and it was the Reverend Andrew Matthews and Frederick Bates who first systematically included Staphylinidae in their lists. The flaws in the Matthews’ list have been discussed elsewhere (Lott, 2009b) and most of the records have been ignored in the current work except for a very small number with details of time and place. Bates’ manuscript list (Bates, 1896) gives odd records of Staphylinidae that are included whenever the reliability of the taxonomy allows. The Victoria County History for Leicestershire list (Bouskell, 1907) gives the status of a few species at that time, but rather perversely ignores the more common species. A card index compiled by Don Tozer gives an assessment of the status of many species in the first half of the 20 th century, but needs careful interpretation because of misidentifications. Individual records in manuscripts and the literature are often difficult to assess, unless voucher material can be located. The reliability of identifications is often open to question because of (i) taxonomic problems inherent in old records and (ii) added difficulties caused by lack of access to the taxonomic literature. Many records listed in manuscript sources that were never intended for serious publication have been ignored in the present work. Collections - the material held by Leicestershire County Council Museums Service has been systematically reidentified and the records extracted for the present work. There is no Matthews material in the Leicestershire collections at Barrow upon Soar and very little Bates material. What Bates material there is has no data. There is Matthews and Bates material elsewhere (Lott, 2009b) but without data and has been translocated from collection to collection so that the original identifications are either lost or obscured. The oldest substantial body of material at Barrow upon Soar dates from the 1890s and relates to collections made by CT Crutwell, CB Headly and JH Woolley. The first two of these collections contain locality data, but the Woolley material is largely without data, the material from the first half of the 20 th century is much more substantial. Unfortunately, the WH Barrow material is largely without data whereas data given by other collectors is much more useful. In the cases of Taylor and Tozer collections are supplemented by their notebooks. Don Tozer and Claude Henderson professed to have neglected the Staphylinidae in their collecting activities but their collections contain a large amount of useful material. The problems connected with misplaced locality labels evident in Henderson’s Carabidae (Lott 2009b) appear to be absent from his Staphylinidae. Their collections, together with that of Taylor, provide a very useful picture of the status of species at this period. Records have also been extracted from the private collection of Tony Drane, a Northamptonshire-based coleopterist who operated from the late 1970s onwards. The majority of records extracted from collections originate from Taylor, Tozer and Henderson (Table 1) who were operating mainly between 1905 and 1955 (Figure 1). If there is any bias in the records from these collections it is in the poor showing of wetland species. The early 20 th century collectors stayed very much on dry land. Table 1: Number of records extracted from collections at Barrow on Soar and elsewhere Collector No. records Collector No. records SO Taylor 485 CT Crutwell 23 CW Henderson 279 TW Tailby 21 D Tozer 273 WH Barrow 12 AB Drane 48 JH Woolley 8 CB Headly 47 B Forrest 8 Unknown 46 JK Bates 7 DG Goddard 28 DJ Foxwell 6 MS Mawson 27 TR Goddard 5 H Broughton 24 KJB Clark 5 HAB Clements 23 D Holyoak 4 VC55 Staphylinids Part 1 4 Figure 1. Collecting dates of VC55 Staphylinidae by early 20 th century collectors. Fieldwork - the vast majority of recent records come from fieldwork carried out by the author. From 1982 to 1990 this mostly consisted of casual collecting in a wide variety of habitats. From 1991 onwards the author concentrated on systematic collecting in wetland habitats (Figure 2). However, up until 1995 other habitats were explored by pitfall trapping projects in association with Jon Daws, Ed Darby, Sally Mousley (Charnwood Wildlife Project) and a number of volunteers working on nature reserves managed by the Leicestershire and Rutland Wildlife Trust. 800 700 600 500 400 300 200 100 0 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Figure 2. Collecting dates of VC55 Staphylinidae by Derek Lott and Jon Daws.