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NOTES ON THE SUFFOLK LIST OF COLEOPTERA: 7 THE GENUS ISCHNOMERA STEPHENS (OEDEMERIDAE)

DAVID R. NASH

Until 1981, only two members of the genus Ischnomera Stephens were included on the British list viz. caerulea (L.) and sanguinicollis (F.) with only the first of these being recorded from Suffolk. In that year I. cinerascens was added to the British list (Skidmore & Hunter, 1981) and in 1988, following the discovery that I. caerulea was actually a mixture of two species, I. cyanea was also added, that name previously having been considered a synonym of caerulea by workers on the Continent (Allen, 1988). It was originally thought that these last two species could only be reliably distinguished by differences in the male genitalia (Allen, loc. cit.). However, Mendel (1990) showed that the pair could be distinguished by differences in the tarsal claws, those of caerulea being distinctly toothed, those of cyanea being simple or only somewhat angled. I. cinerascens is dull sage green with distinctly grey elytral pubescence – characteristics which help separate it in the field from I. cyanea and caerulea which are both bright green to blue with barely visible elytral pubescence. All the species breed in rotting wood, with that of elm appearing the most favoured pabulum in this country. Adults can be found in rotten wood but are most frequently taken by beating or sweeping.

Literature records of I. caerulea prior to these discoveries and unsupported by voucher specimens cannot be accepted, as any one of three species could be involved although most are likely to refer to cyanea. I. caerulea was afforded a place in Morley’s (1899) Suffolk list on the basis of the record given in Stephens (1839) and was in Elliott’s list (1936) of 104 species requiring confirmation. There are no Suffolk specimens in the Claude Morley or Chester Doughty collections at Ipswich Museum.

Ischnomera cinerascens (Pandellé) RDB 2 I. cinerascens was originally added to the British list on the basis of specimens taken at Duncombe Park, North Yorkshire and Moccas Park, Herefordshire (Skidmore & Hunter, 1981). Published records now also exist for Bucking-hamshire (Alexander, 1987), Oxfordshire (Campbell, 1996), Worcestershire (Whitehead, 1996), Leicestershire (Lott, 1996) and Northamptonshire, Gloucestershire and Warwickshire (Alexander & Foster, 1998). Originally considered the rarest of our species (RDB 2, Vulnerable status in Hyman, 1992) it is proving to be more widely distributed than at first thought, with an increasing number of recent finds, although study of old collections has only detected a single example. The reason for this last fact is unclear although it has been suggested that collectors chose to retain the brightest specimens of Ischnomera for their collections passing over individuals of this species in favour of “caerulea”. The beetle chiefly occurs in pasture-woodland although there are some recent records from secondary woodland.

On 25 May 1999 I beat a single example of I. cinerascens from an old dead, dry hawthorn (Crataegus) in Horringer Park (TL 8162) on the Ickworth Estate near Bury St Edmunds. This date accords well with the flight period suggested by Alexander & Foster (loc. cit.).

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Ischnomera caerulea (L.) This rare species (RDB 3 status in Hyman, 1992) is currently known from Hampshire, Surrey, Berkshire and Herefordshire (Mendel, 1990). It occurs in ancient broad-leaved woodland and pasture-woodland. I swept a single example of caerulea on 18 June 1983 near the Hall at Shrubland Park, Barham (TM 1252).

Ischnomera cyanea (F.) This, the commonest of the genus, occurs not only in ancient broad-leaved woodland and pasture-woodland, but also in hedgerows and downland. It is afforded Notable B status in Hyman, 1992. All records which follow are my own except where indicated: Barton Mills Heath (TL 77) – 24. v. 1952 (A. A. Allen) ; Rougham, near Bury St Edmunds (TL 9163) – 28. v. 1997, 1 swept; 17. vi. 1998, 1 beaten in Rougham Park; Ramsey Wood, Hintlesham (TM 0643) – 31. v. 2000, 2 swept in damp ride; Hintlesham Great Wood (TM 0743) – 13. vi. 2000, beaten in numbers from elder bloom (Sambucus nigra) on edge; Shrubland Estate, Coddenham (TM 1153) – 27. v. 1980, 1 beaten hawthorn (Crataegus) bloom; 28. v. 1986, 1 swept; Shrubland Estate, Coddenham (TM 1252) – 29. v. 1970, 1 dead in cobweb in soggy rothole of small elm (Ulmus sp.); 29. v. 1971, 3 dug from same elm rothole; 31. v. 1979, 1 swept; 09. vi. 1984, 1 swept; Barham (TM 1351) – 26. v. 1980, from dead elm (Ulmus sp.) (H. Mendel); Shrubland Estate, Hemingstone (TM 1153) – 18. vi. 1983, 1 swept.

Acknowledgements I thank: Messrs. H. Mendel and A. A. Allen for allowing me to include their unpublished records; Mr. D. Lampard (Keeper, Natural History) for access to the Morley and Doughty collections at Ipswich Museum; Mr. P. Robinson (English Nature) for arranging access to Hintlesham Woods; the following for allowing me to record on their property or that in their care - Mr. K. Alexander (National Trust, Ickworth Park), Lord de Saumarez (Shrubland Park), Mr. R. Vonk (R.S.P.B. Warden, Ramsey Wood), Mr. G. Agnew (Rougham Estate).

References Alexander, K. N. A. (1987). Ischnomera cinerascens Pand. (Col. : Oedemeri-

dae) in Buckinghamshire. Entomologist’s Rec. J. Var. 99: 226. Alexander, K. N. A. & Foster, A. P. (1998). Ischnomera cinerascens Pandellé

(Oedemeridae) new to Gloucestershire and Warwickshire. Coleopterist 7: 22.

Allen, A. A. (1988). A fourth species of Ischnomera Steph. (Col:Oedemeridae) in Britain. Entomologist’s Rec. J. Var. 100: 199–202.

Campbell, J. M. (1996). Ischnomera cinerascens (Pandellé) (Oedemeridae) in Oxfordshire. Coleopterist 5: 24.

Elliott, E. A. (1936). Critical notes on our beetles. Trans. Suffolk Nat. Soc. 3: 121–128.

Hyman, P. S. (revised Parsons, M. S.) (1992). A review of the scarce and threatened Coleoptera of Great Britain. Part 1. U. K. Nature Conservation: 3. Peterborough: Joint Nature Conservation Committee.

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Lohse, G. A. (1982). 13. Nachtrag zum Verzeichnis der mitteleuropäischen Käfer. Ent. Blätt. 78: 115–126.

Lott, D. A. 1996. In: Coleoptera Report, 1995 Annual Exhibition. Br. J. Ent. Nat. Hist. 9: 235.

Mendel, H. (1990). The identification of British Ischnomera Stephens (Coleoptera: Oedemeridae). Entomologist’s Gaz. 41: 209–211.

Morley, C. (1899). The Coleoptera of Suffolk. Plymouth. Skidmore, P. & Hunter, F. A. (1981). Ischnomera cinerascens Pand. (Col.,

Oedemeridae) new to Britain. Entomologists’s mon. Mag: 116(1980): 129–132.

Stephens, J. F. (1839). A Manual of British Coleoptera. Longmans. Whitehead, P. F. 1996. The notable arboreal Coleoptera of Bredon Hill,

Worcestershire, England. Coleopterist 5: 45–53.

David R. Nash