Enicmus testaceus (S.) (Col. Latbridiidae)

ENICMUS TESTACEUS (S.) (COL. LATHRIDIIDAE) apparently new to the SufFolk List with notes on some other Coleoptera associated with myxomycete fungi DAVID R .

NASH

collecting in Bentley Long Wood, near Ipswich (TM 108393) on May 7th, 1972, a single specimen of the very locally distributed Lathridiid Enicmus testaceus (S.) was found among the spores of a myxomycete fungus on an old fallen cherry trunk (Prunus lavium L.). I am not aware of any published records for the county, and there are no SufFolk specimens in the Claude Morley collection. My only previous encounter with this Enicmus was in Bramshaw Wood in the north of the New Forest, Hants. in August, 1971. In the latter locality the beetle was found in large numbers in a myxomycete growing beneath the loose bark of a mature, fallen, beech trunk.

WHILST

Although E. testaceus has long been recognised as one of a small number of Coleoptera which feed specifically upon myxomycete fungi, very little information has been available until recently, concerning the species of fungi involved. The authors of our two Standard works on the identification of British Coleoptera, Fowler (1887-91) and Joy (1932), both merely refer to 'powdery fungi' when discussing the microhabitats of those species associated with the slime fungi. In an important recent paper, however, Ing (1967) summarises much of the available information on those organisms which use myxomycetes for food. He records E. testaceus from Fuligo septica (L.) Web., and Reticularia lycoperdon Bull. Crowson (1962) has also recorded this species from Reticularia.

In the New Forest locality, the Enicmus was found in Company with another scarce myxomycete feeder, Sphindus dubius Gyll.

(Sphindidae). This particular species was added to the Suffolk List by Tomlin who bred it out of a fungus (type unspecified) found at Foxhall, near Ipswich (Tomlin, 1900; Morley, 1915).

I have not so far found Sphindus in Suffolk and I am aware of no further records of the species in the county. There are no Suffolk specimens in the Morley collection. Neither Ing loc. cit. nor Pope (1953) provide details of the specific fungi with which the beetle is associated, so that information concerning the myxomycete food of Sphindus would be extremely useful.

The other British Sphindid, Aspidiphorus orbiculatus Gyll. also feeds on myxomycetes. Brown (1943) records the beetle feeding on Comatricha nigra (Pers.) Schroet in Norfolk; Skidmore and Johnson (1969) record it from Fuligo septica in Merioneth; whilst White (1972) has recently recorded it from a species of Arcyria ('probably denudata L.') in Kent. Since there seems to be only

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one published record of Aspidiphorus in the county—one swept

by Morley in Cutler's Wood, Fr est cm in 1904 (Morley, 1915)— and this specimen is the only Suffolk representative in the Morley collection, it would seem worth placing on record my capture of a single example in a myxomycete growing on a small pine log on the ground under some mature Scots Pine (Pinus sylvestris L.) on the edge of Tunstall Common, near Woodbridge ( T M 380554) on August 26th, 1971. At Grovely Wood in Wiltshire I have found specimens inside the damp, rotting interior of a felled Horse Chestnut (Aesculus hippocastanum L.) in a myxomycete on a pine log.

In addition to the three species discussed above, Ing loc. cit. records a further six species of Coleoptera which appear to show a strong preference for myxomycetes viz. *Anisotoma humeralis (F.), A. castanea (Hb.), A. orbikularis (Hb.), *Agathidium rotundatum Gyll., A. sphaerulum Reitt. and *A. rhitioceros Sharp. (It should be noted that the last species is now known as arcticum Thomson—vide Johnson, 1966.) Species asterisked* have been recorded for Suffolk.

A species not referred to by Ing is Agathidium varians Beck.

A reference to this insect by Morley seems worthy of mention.

Morley (1933) records an example of this Agathidium Walking on the new sawn end of an old Elm trunk in Shrubland Park, Barham, and comments that it was 'pretty surely hunting for fungus spores'. This is a purely speculative comment, but it is interesting that in the very next sentence he notes that under another tree trunk (presumably—from the context—close by) was the myxomycete fungus Arcyria ferruginea Saut.

I am not aware of any published information on how to discover and capture myxomycete-feeding Coleoptera, so that, by way of conclusion, a note here concerning my own method may not be out of place. Whenever possible I carefully place the log, etc. on which the fungus is growing, onto a strong, white, plastic sheet. I then blow extremely gently onto the fungus so as to remove the spore dust from the fruiting bodies. If any beetles are present, I have found that they will usually remain clinging to the now exposed surface on which the fungus was growing.

In my experience, the insects rarely drop off the log, but the plastic sheet is a safeguard in the event of such a happening.

Even where the fungus is growing on the vertical face of a large tree trunk too heavy to move and the sheet is difficult to position because of surrounding herbage such as brambles, the often very active Anisotoma humeralis (found quite commonly in the county) rarely releases its grip on the wood when the spores are blown away.

From the above notes concerning the association of one specific order of insects with myxomycetes, it is evident that the ecology

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of s u c h f u n g i is still i m p e r f e c t l y k n o w n , a n d it is t o b e h o p e d t h a t t h e p r e s e n t p a p e r m a y d r a w a t t e n t i o n to, a n d s t i m u l a t e a g r e a t e r i n t e r e s t in, t h i s n e g l e c t e d field.

Acknowledgements I s h o u l d like t o t h a n k m y f r i e n d M r . C . B a r h a m f o r c h e c k i n g h i s o w n r e c o r d s of t h e s p e c i e s d i s c u s s e d h e r e , a n d t h e C u r a t o r a n d M r . F . W . S i m p s o n of t h e I p s w i c h M u s e u m f o r a l l o w i n g m e access t o t h e M o r l e y c o l l e c t i o n a n d diaries. I n a d d i t i o n , I t h a n k M r . A . R . B u x t o n f o r a l l o w i n g m e t o s t u d y o n h i s e s t a t e at B e n t l e y .

References Brown, R. M . S. (1943). Miscellaneous observations—Coleoptera.

Trans. Norf. Norm. Nat. Soc. 15, 374.

Crowson, R. A. (1962). Observations on Coleoptera from Scottish oakwoods. Glasg. Nat. 18, 177-195.

Fowler, W . W. (1887-91). The Coleoptera of the British Islands.

Reeve and Co. Ing, B. (1967). Myxomycetes as food for other organisms. Proc. S. Lond. ent. nat. Hist. Soc. 1967, 18-23.

Johnson, C. (1966). Some amendments to the British List of Anisotomidae (Col.). Entomologist 99, 106.

Joy, N . H . (1932). A Practical Handbook of British Beetles.

Witherby.

Morley, C. (1915). The Coleoptera of Suffolk: First Supplement.

J. H. Keys, Plymouth.

Morley, C. (1933). Notes on an excursion to Shrubland Park, Barham.

Trans. Suffolk Nat. Soc. 2, lxxxiv.

Pope, R. D . (1953). Handbooks for the Identification of British Insects—• Coleoptera: Coccinellidae and Sphindidae. vol. V, part 7. Royal Entomological Society.

Skidmore, P. and Johnson, C. (1969). A preliminary list of the Coleoptera of Merioneth, N o r t h Wales. Entomologist's Gaz. 20, 139-225.

Tomlin, B. (1900). Various Coleoptera records for Suffolk. Ent. Ree. 12, 78.

White, I. M . (1972). Aspidiphorus orbiculatus Gyll. (Col. Sphindidae) and Anisotoma orbicularis (Herbst) (Col. Anisotomidae) in a Myxomycete fungus. Entomologist's mon. Mag. 108, 256.

David

Ridley

Nash, 266 Colchester Road, Manningtree, Essex.

Lawford,

near