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Suffolk Natural History, Vol. 34 BRECKLAND - A UNIQUE HABITAT FOR BEETLES R. COLIN WELCH
Historically heathlands in Britain appear to have received little recognition as a valued habitat for Coleoptera. W. E. Sharp in his book on 'Common beetles of our countryside', probably published just after the First World War, devotes a whole chapter to moorland beetles with only a passing comment that "No doubt wide areas exist in Surrey, in Berkshire, and in Hampshire which can grow little beside heather and ling, but these expanses we must call Heaths not Moorlands". He dismisses these further by adding that "They lack much ofthe distinctive insect fauna ofthe great moorlands ofthe north and north-west". Even in Cooter's latest edition of 'A Coleopterist's Handbook' (1991) the introductory chapter on 'Collecting from sample habitats' makes no specific mention of heathland as a habitat worthy of attention at any time of the year. Webb (1986), in his New Naturalist book on 'Heathlands' states that "There are relatively few species which can be considered unique and solely dependent on heathland; many species occur in other habitats, and offen select heathland because it provides a certain ränge of physical conditions". He categorises heathland invertebrates into those phytophagous species associated with Calluna, Erica, Ulex, Cytisus and other characteristic heathland plants, and those requiring particular physical conditions, such as sandy soil, hot open spaces, or dwarf shrubs which are only available on heathland. He further stresses the general paucity of herbivorous insects on heathland plants by quoting McNeil & Prestige's (1982) findings that 100 sweeps of an ericaceous Community will yield 150-270 insects representing up to six species, compared with ten times that number of insects, of up to 20 species, from a similar sample taken from Holcus mollis grassland. Despite its apparent poor press, any coleopterist asked the value of heathland would immediately stress its importance, and Kirby (1992) lists many rare and uncommon species at risk from fragmentation of heathland habitats. However, most of the species we may regard as 'typical' of heathland are not restricted to such areas, and Morley (1908), in an early account of 'Insects of the Breck', states that "It is not so much the hope of turning up insects which are found nowhere eise that attracts the entomologist to this district, as the unusual number of generally rare kinds to be met with within a small area; they are to be found elsewhere, but at long intervals and not associated as is here the case". He goes on to add that "Commoner kinds too occur in greater profusion than in most districts ". Morley attributed the rieh Breckland fauna to "The dryness of the soil rendering their most deadly enemy, mould, comparatively non-existent". He also regarded the remoteness of the Breck, and the scarcity of farmers and, to a lesser extent, keepers as major contributory factors. Although the other contributors to this conference have discussed the flora and fauna of heathlands in general, I will limit my account to that area of Breckland straddling the border of Norfolk and Suffolk. When Morley (1897) spent ten days in the Breck in 1896 he considered that Suffolk had been "One ofthe most prolific of English Counties" (for Coleoptera) when Rev.W. Kirby
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collected there at the end of the eighteenth Century, but had been largely deserted since. However, Walker (1885) had visited the area 11 years earlier and likened it to the coast of Kent at Deal. When Morley visited he was unable to find the 'Brandon sandhills' and collected at Wangford Warren instead. Morris (1975) remarks that "For some time afterwards the Brandon Region, and later Barton Mills District, were well-known localities for Coleoptera, but the significance of the Breckland as a whole was slow to be appreciated". Today the only relicts of the once extensive inland dunes are to be found on the Suffolk Trust's reserve at Wangford Warren. Another former large area of similar habitat was destroyed during the construction of the USAF base at Lakenheath, although a recent survey by English Nature staff (Key, et al, 1992) showed that many elements of the associated fauna persist there. In April 1991 the Forestry Commission held a symposium in Cambridge on 'Thetford Forest Park; the ecology of a pine forest', the proceedings of which were not published until last year (Ratcliffe & Claridge, 1996). In a joint paper with Peter Hammond of the Natural History Museum (Welch & Hammond, 1996) we demonstrated the importance of non-afforested areas for a considerable number of Red Data Book and Nationally Notable species of Coleoptera within the bounds of Thetford Forest. Hammond had built up an inventory of Breckland beetles over many years both from all known published records and from his own and other unpublished sources. I have used this data extensively in preparing this account, but clearly I can only highlight a few of what I consider to be the more significant or specialised species of beetle occurring on the Breckland heaths. Despite being a major constituent of any heathland's flora, Calluna has an impoverished associated beetle fauna. In my experience probably the most ubiquitous species is the small, red-legged weevil Micrelus ericae, which is equally widely distributed on species of Erica. The species commonly known as the 'heather beetle', the chrysomelid Lochmaea suturalis, can be abundant on northern heather moors but on southern heaths it is generally less numerous with major outbreaks occurring every ten years or so. During such years severe defoliation occurs and can kill patches of heather allowing other plants to colonize and alter the structure of the Vegetation. Three other leaf beetles in the genus Altica\ A. britteni, A. ericeti, and A. oleracea, have been recorded feeding on both Calluna and Erica species, although A. oleracea has other hosts. There is some doubt as to whether A. britteni is a northern race of the southern A. ericeti.. Both have been observed damaging young heather (Port & Guile, 1986). Four members of the weevil genus Strophosoma have similar feeding habits with S. sus the most common and widespread on both host genera. Other associated weevils include Coniocleonus nebulosus found among the roots of Erica, but restricted to southern and eastern heathlands; and Acalles ptinoides, a species which, although frequently found in leaf litter under heather, is also found in woodland litter. The colourful chafer Anomala dubia is typically found on coastal dunes but does occur in Breckland and is said to feed on Calluna. Majerus (1994) mentions two ladybirds with indirect associations with heather. Coccinella hieroglyphica is a predator of larval Lochmaea, whereas Chilocorus bipustulatus which he refers to as the 'heather
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ladybird', preys on coccid bugs which feed on both heather and birch. Both these ladybirds have near identical distributions on the southern heaths and northern English moors, but the distribution of the former species extends into Scotland. Although dry heathlands are home to many species of ground beetle three appear to have a direct association with Calluna. Amara infima is only known from sandy heathland and dune sites in southern England, East Anglia and Glamorgan. This species may escape detection as it aestivates in summer and breeds during the late autumn or early winter months. The other two species, Trichocellus cognatus and Bradycellus collaris, both have northern distributions although the latter has been recorded from a couple of Breckland sites. One could list a number of Coleoptera which feed specifically upon Cytisus, Ulex, or even Betula species, all of which are common constituents of any heathland flora, but as these plants and their associated insects are widely distributed away from heathlands I have chosen to omit them from this account. There are many more phytophagous beetles, especially among the curculionid weevils, associated with herbaceous plants which grow on sandy soils and collectively typify the unique nature of Breckland's coleopterous fauna. Many Nationally Notable species occur commonly in the open Breck (see Hyman & Parsons, 1992, 1994), but by no means all have host plants that are especially restricted in their distribution. Good examples are to be found among the weevils of what was formally the genus Ceutorhynchus. Virtually all the Notable British species are known to occur in Breckland. C.unguicularis was first recorded in Britain feeding on hairy rock cress, Arabis hirsuta, at Mildenhall in 1962 and is still known only from a further three Vice Counties. C. parvulus is associated with Smith's pepperwort, Lepidium heterophyllum, and although not listed from the Breck by Hyman & Parsons (1992) Hammond has a pre-1970 record (Welch & Hammond, 1996). C.pulvinatus is primanly a Breckland species feeding on flixweed, Descurainia sophia, with recent records only from this region. C. hirtulus is predominently a maritime species associated with common whitlow grass, Erophila verna, but probably also feeds on Descurainia, which is also one of the cruciferous host plants for the common C. rapae. A Notable flea beetle, Psylliodes sophiae is also restricted to this host and is only known from Breckland, Cambridgeshire and Huntingdonshire. C. pumilio and C. atomus both feed on shepherd's cress, Teesdalia nudicaulis, while C. resedae feeds on weld, Reseda luteola. Among those species recently transferred to different genera (Morris, 1991) Mogulones geographica feeds on viper's bugloss, Echium vulgare, also host to four species of flea beetle in the genus Longitarsus (Bullock, 1992) including L. guadriguttatus, a Notable species with most recent records from East Anglia; Sirocalodes mixtus on species of fumitory; Calosirus terminatus on wild carrot, Daucus carota, Microplontus triangulum and Trichosirocalis barnevillei on yarrow, Achillea millefolium, together with the chrysomelid Chrysolina marginata-, and lastly Hadroplontus trimaculatus on musk thistle, Carduus nutans. Hyman & Parsons (1992) list seven Notable species in the weevil genus Gymnetron, all of which occur in Breckland, but most feed on species of
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Veronica growing in wetland habitats. However, two species, G. collinum and G. linariae, together with a third common species, G. antirrhini, feed on common toadflax, Linaria vulgaris, which is also host to a Notable chrysomelid, Chrysolina sanguinรถlenta. A selection of some other Breckland Curculionoidea of note include Acentrotypus brunnipes (formerly Apion, see Morris, 1993), which feeds on cudweed, Filago vulgaris, Tychius guinguepunctatus feeding on bitter vetch, Lathyrus montanus; Cionus longicollis on great mullein, Verbascum thapsus, and Gronops lunatus on various spurrey, Spergularia species; while common Stork's bill, Erodium cicutarium is host to Limobius mixtus and Hypera dauci. In addition to their diverse array of phytophagous Coleoptera lowland heaths like the Breck provide the types of open, sandy, habitats required by many other species, including a number of carabid ground beetles. Most visitors to heathlands will have noticed the green tiger beetle Cicindella campestris, an active predator which flies readily on hot sunny days, but will be unaware of its larvae which live in vertical burrows in the soil waiting to seize any unwary passing invertebrate. Most Carabidae are predators both as adults and larvae but several heathland species feed as adults on a variety of plant seeds. Among the more notable species which have a mainly southern distribution are Amara fulva, A. consularis, Harpalus puncticollis and H. smaragdinus. Until 1980 it was thought that only two species of predatory Carabidae of the genus Cymindis occurred in Britain; C. vaporarium, a species of wet upland Sphagnum bogs, and C. axillaris, a species of southern heaths. When examining insect fragments from stone curlew pellets collected near Icklingham during September 1980, in addition to a Single C. axillaris, Hammond (1982) identified a Single head capsule of a third species, C. macularis, an addition to the British List. Later Williams (1984) discovered that he had collected three specimens at Barton Mills in June 1966, and Owen and Mendel (Owen, 1990) found a Single specimen each near Thetford in June 1989. These remain the only known British records and this species appears to be confined to Breckland. One of the most distinctive features of the Breckland beetle fauna is the presence of a number of species whose British distribution is otherwise restricted to coastal dune systems. Clarke (1908) referred to the occurrence of coastal plants, insects, and birds on Norfolk and Suffolk heaths. He reported coastal insects as present on 5 out of 11 Norfolk heaths, and 6 out of 12 Suffolk heaths. In the same year Morley (1908) also highlighted this same phenomenon and mentions that the small dark tenebrionid Melanimon tibiale was first found in England at Barton Mills and Elvedon by Rev.W. Kirby in 1797. Although predominently a coastal species it has been recorded from a number of inland sites. Two other coastal Tenebrionidae, Crypticus guisguilius and Ctenopius sulphureus, were recorded at Brandon in 1885 by Walker (1885). The former species was found to be widely distributed throughout the Breck by Morley (1908) although Brendell (1975) reports it from only three other inland localities. Among the Carabidae there are three species which occur in the Breck whose distribution is otherwise mainly coastal. The largest
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of these is Broscus cephalotes, more usually found under driftwood, etc., on sandy coasts and coastal dunes. This species was found "in more or less abundance" by Walker in 1885 but does not appear to have been recorded again in Breckland until 1973 when it was found at Wangford Warren (Morris, 1975). Duffey (1976) considered it to be very rare in the Breck in the 1970s. Broscus has also been recorded from many other sandy inland sites but such occurences are often sporadic and follow periods of hot dry weather. The species is winged but there is considerable doubt as to whether it is able to fly and, if not, how it colonises these inland sites. Morley (1897) recorded two other coastal Carabidae at Lakenheath Warren in September 1896, Harpalus vernalis and H. anxius. In a post-script to this paper G. C. Champion commented that these were probably their first British records from an inland locality. The present day distribution of H. vernalis is still almost restricted to Breckland with a few records from the south coast and central England. H. anxius is more widespread around the English coastline with a number of inland records from sandy heaths and sandpits. H. attenuatus, although less common, has a similar concentration of inland records from the Breck. Two further rare species of this genus, H. froelichi and H. servus, are known from dunes on the south and east coasts and the occasional sandpit or sandy heath inland. Recent records for both species are all from East Anglia. Foster (1988) recorded the former rarer species as common at a mercury vapour light trap at Foxhole Heath in late June 1987. Another carabid with a similar distribution is Masoreus wetterhalli which occurs along the south coast, on the north Norfolk coast, and in the Breck. Calathus erratus and C. ambiguus are two other examples of coastal Carabidae which frequent Breckland. Other Notable Breckland Coleoptera with predominently coastal distributions include the scarabaeid Psammodius asper, the elaterid click beetle Cardiophorus asellus, also well known from the Surrey heaths; the colydud Orthocerus clavicornis with its distinctive clubbed antennae, associated with Peltigera liehen heaths; and the anthicid Notoxus monocerus with the horn-like forward projection on its pronotum. The weevil Philopedon plagiatus is widely distributed around the entire British coastline but has also been recorded from a number of inland sites. Morris (1987) reviews these and details records from the Suffolk Breckland. Other coastal Curculionidae include Sitona griseus which feeds at the roots of various leguminous plants, and Cleonus piger, whose larvae develop in the stems of creeping thistle, Cirsium arvense, which is also the host plant for another Notable weevil, Tanymecus palliatus. Aizobius (formerly Apion) sedi is unique in feeding on Crassulaceae, principally on species of Sedum, and its larvae mine the leaves and stems. This species occurs chiefly on the coast but has been recorded from the Breck. Historically the sandy Breckland soils proved ideal for the establishment of warrens and although these are long gone the rabbit remained and proved invaluable in maintaining open areas and supporting a very specialised element of the Breckland beetle fauna. One such species, unique to Breckland, is the small scarabaeid Diasticus vulneratus. Morley (1908) first recorded this species as British when he found one beneath the remains of a rabbit at Brandon in June 1902. The following year he and A. J. Chitty collected one
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each at arms length down a rabbit burrow, and in May 1907 Chitty returned and found a fourth specimen by the same method. To this day Diasticus has only been found on the open heaths of the Suffolk Breckland. Among the dung-feeding Geotrupidae the so-called minotaur beetle Typhaeus typhoeus seems to have a particular association with rabbit droppings which it buries at some depth in a vertical tunnel as food for its developing larvae. At least two other Scarabaeidae have an association with rabbits. Euheptacaulacus villosus, which is more usually found on sandy coastal sites, and Aphodius distinctus which Foster (1992) recorded swarming over rabbit dung at East Wreatham Heath in the Norfolk Breck in October 1991. DĂźring the same visit he also recorded the staphylinid Ouedius nigrocaeruleus from a rabbit burrow. Other inhabitants of the burrows and underground nests of rabbits include the staphylinids O. puncticollis and Aleochara cuniculorum; the carabid Laemostenus terricola; the histerid Onthophilus punctatus and Leiodidae such as Catopidius depressus and species of Choleva. The sandy Breckland soils may not, at first sight, appear an ideal substrate for fungi but species of Lycoperdon, and other puff-ball fungi, do occur there. These occasionally growing to a considerable size and provide food for larvae and adults of four very rare beetles. The anobiid Caenocara afftnis is known in Britain from only eight specimens bred from a puff-ball, Lycoperdon perlatum, found at Barton Mills in 1917. A second species, C. bovistae, is more widely distributed, but none-the-less rare, in L. bovistae and Bovista plumbea which may occur in woodland as well as heathland. Two Endomychidae, Lycoperdina succincta and L. bovistae, have been found in the above and other species of Lycoperdon. Odontaeus armiger, unlike other Geotrupidae, does not feed on dung but is associated with subterranean fungi. This species is most frequently taken in mercury vapour light traps in chalky districts and at various sites throughout the Breck. As the purpose of this conference has been to emphasise the importance of lowland heaths I have attempted to limit my comments on Breckland Coleoptera to those species associated with habitats in the open sandy ares. Approximately 1700 species of Coleoptera have been recorded from within Breckland. In addition to one or two species which have not been recorded this Century, and four species probably now extinct in Britain, there are approximately 50 others for which no post-1920 are known. From the overall total 460 species (27%) are included in the Red Data Book and Nationally Notable categories used by Hyman & Parsons (1992, 1994), nearly 40% of which are regarded as species of open country (Welch & Hammond, 1996) and, of these, 29 are Red Data Book or prospective RDB species. As much of Breckland today is covered by Forestry Commission plantations one would expect most of the rarer non-heathland beetles to be associated with woodland habitats. In fact a slightly greater number are to be found in wetland habitats. Following access to Stanford Practical Training Area many rare aquatic beetles have been found in the fluctuating mires, pingoes and bomb craters, to which can be added those species confined to small relict fen communities. Over the past 20 years or so there has been a welcome upsurge of interest in the coleopterous fauna of Breckland. It is quite possible that further studies
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of less well known and taxonomically difficult groups could see a total beetle fauna approaching 2000 species. Howard Mendel and David Nash have started collecting records towards the production of an up to date checklist of Suffolk Coleoptera and Martin Collier is well on the way to producing a similar list for Norfolk. I am confident that the results of their labours will only serve to emphasise the unique nature and national importance of Breckland. Nomenclature follows Kloet & Hincks (1977) with weevils updated in accordance with Morris (1991 & 1993). Rcfcrcnccs Brendell, M. J. D. (1975). Coleoptera, Tenebrionidae, Handbk. Ident. Br. Insects, vol. V, Part 10, Royal Entomological Society, London. Bullock, J. A. (1992). Host plants of British beetles: a list of recorded associations, Amateur Entomological Society, Feltham. Clarke, W. G. (1908). On some Breckland characteristics. Trans. Norfolk Norwich Nat. Soc., 8: 555-578. Cooter, J. (1991). A coleopterist's handbook, 3rd edition, Amateur Entomological Society, Feltham. Duffey, E. (1976). Breckland, pp. 62-77, In: Nature in Norfolk, a heritage in trust, Jarrold & Sons, Norwich. Foster, A. P. (1988). 1987 Annual Exhibition - Coleoptera. Br. J. Ent. Nat. Hist., 1: 40. Foster, A. P. (1992). 1991 Annual Exhibition - Coleoptera. Br. J. Ent. Nat. Hist., 5: 73. Hammond, P. M. (1982). Cymindis macularis (Fischer & Waidheim) (Col., Carabidae) - apparently a British species. Entomologist's mon. Mag., 118: 37-38. Hyman, P. S & Parsons, M. S. (1992). A review of the scarce and threatened Coleoptera of Great Britain, Part 1. UK Nature Conservation No. 3, Joint Nature Conservation Committee, Peterborough. Hyman, P. S. & Parsons, M. S. (1994). A review of the scarce and threatened Coleoptera of Great Britain, Part 2. UK Nature Conservation, No. 12, Joint Nature Conservation Committee, Peterborough. Key R. S„ Drake, M. C„ Sheppard, D. A. & Procter, D. (1992). An invertebrate Survey of RAF Lakenheath SSSI on 2Ist June 1992. English Nature Research Report, No. 47, English Nature, Peterborough. Kirby, P. (1992). Habitat management for invertebrates: a practical handbook, Joint Nature Conservation Committee, Peterborough. Kloet, G. S. & Hincks, W. D. (1977). A check list of British insects. Handbk. Ident. Br. Insects, vol. XI, Part 3, Coleoptera & Strepsiptera, revised by R. D. Pope. Royal Entomological Society, London. Majerus, M. E. N. (1994). Ladybirds, New Naturalist, Collins, London. McNeil, S. & Prestige, R. A. (1982). Plant nutritional strategies and herbivorous Community dynamics, In: Visser, J. H. & Minks, A. K. (eds.), Proc. 5th Int. Symp. insect-plant relationships, Wageningen 1982, Wageningen, Pudoc. Morley, C. (1897). Ten days' collecting (Coleoptera) at Brandon, Suffolk. Entomologist's mon. Mag., 33: 9-11. Trans. Suffolk Nat. Soc. 34 (1998)
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Morley, C. (1908). The insects of the Breck, Trans. Norfolk Norwich Nat Soc 8: 579-586. Morris, M. G. (1975). Broscus cephalotes (L.) (Col., Carabidae) found inland. Entomologist's mon. Mag., 110(1974): 172. Morris, M. G. (1987). The distribution and ecology of Philopedon plagiatus (Schaller) (Col.; Curculionidae), with particular reference to inland records. Entomologist's Ree. J. Var., 99: 11-20. Morris, M. G. (1991). A taxonomic check list of the British Ceutorhynchinae, with notes, particularly on host plant relationships (Coleoptera: Curculionidae). Entomologist''s Gaz. ,42: 255-265. Morris, M. G. (1993). 'British Orthocerous Weevils'; Corrections and new information (Coleoptera, Curculionoidea). Entomologist's mon Mag 129 23-29. Owen, J. A.(1990). Exhibit at BENHS Meeting, 14 December 1989, Br J Ent Nat. Hist., 3: 121. Port, C. M. & Guile, C. T. (1986). Outbreaks of flea beetles, Altica spp., on heather and other flowering plants. Plant Pathology,35: 575-577. Ratcliffe, P. & Claridge, J.(1996). Thetford Forest Park: the Ecology of a Pine Forest, Forestry Commission Technical Paper, No. 13, Forestry Commission, Edinburgh. Sharpe, W. E. (no date). Common beetles of our countryside, S.W. Partridge, London. Walker, J. J. (1885). Notes on Coleoptera at Brandon, Suffolk. Entomologist's mon. Mag., 22: 86-87. Webb, N. R. (1986). Heathlands, New Naturalist No. 72, Collins, London. Welch. R. C. & Hammond, P. M. (1996). Breckland Coleoptera, pp.92-102, In: Ratcliffe, P. & Claridge, J. (eds.) Thetford Forest Park: the ecology of a pine forest. Forestry Commission, Edinburgh. Williams, S. A. (1984). Cymindis macularis (Fischer & Waldheim) (Col., Carabidae) in Thetford Chase. Entomologist's mon. Mag., 120: 107. Dr. R. C. Welch The Mathorn House Hemington Oundle Peterborough PE8 5QJ
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