HYMENOPTERA 2003

Geoff Trevis

The hot, dry weather of 2003 has generally been good for hymenoptera nationally, with new or rare immigrant species being recorded. In my experience, the only exception to this has been the ants that have avoided desiccation by remaining deep within their nests, at least during the hottest part of the day. Some progress has been made with recording in Worcestershire though it remains a seriously under recorded county.

Two species in particular have elicited comment. Hornets have been comparatively abundant with records from places where they have not been noted for years. It is good to see these spectacular, though generally placid, insects doing well. Their sheer size causes panic amongst the general public and we must continue to push the message that, in fact, if you leave them alone they will leave you alone and are certainly not inclined to undertake unprovoked attack. The other species that has appeared in large numbers is the cuckoo bee Bombus (Psithyrus) sylvestris. Not a rare species it has nonetheless been recorded in unprecedented numbers at sites across the county. The only reservation we have with this observation is that the apparent increase in numbers may have more to do with those of us interested in this group getting our “eye in” and learning the jizz rather than a genuine population increase . Only time will tell which is the correct situation.

Some of the other species recorded during the year are:

Andreninae (Mining Bees)
Andrena wilkella, A, scotica, A. fulvago, A, flavipes, A. fulva, A. trimmerana, A. labialis, A. chrysosceles, A. cineraria, A. thoracica and A. pubescens.

Nomada (Nomad Bees)
Nomada lathbuiana (RDB3), N. fucata, N. panzeri.

Anthophorinae
Anthophora plumipes

Bombinae
Bombus lucorum, B. lapidaries, B. pascuorum, B. hortorum, B. ruderarius, B (Psithyrus) sylvestris. Also, a possible B. ruderatus (dark form).

Megachilinae
Megachile willughbiella

Halictinae
Lasioglossum lativentre, L. laevigatum, L. leucozonium, Halictus rubicundus.

Colletinae
Colletes succinctus, C. daviesanus

Chysidinae (Ruby Tailed wasps)
Chrysis ignita

Eumenidae (Potter and Mason wasps)
Ancistrocerus nigricornis

Sphecidae
Ectemnius cephalotes

Vespidae (social wasps)
Vespula vulgaris, V. germanica, Dolichovespula sylvestris, D. media, D. saxonica

Formicidae (ants)
Lasius niger, L. flavus, F. rufa, F. fusca, Myrmica ruginodis, M. rufa.

An interesting experiment I tried was collecting the hymenoptera that emerged from a Robin’s Pincushion or Bedeguar gall. The gall causer, Diplolepis rosae, was not the most numerous of the emerging insects. The most numerous were parasitic chalcid wasps. I have not got definite identification for all of them but I do have the black Eurytoma rosae and the beautiful, metallic Torymus bedeguaris There was also a single Ichneumon, Orthopelma mediator. I certainly intend to repeat the experiment and include a wider variety of galls.

In addition I have a box of pinned specimens and tubes with unset specimens awaiting identification that will undoubtedly add to this list. My thanks to everybody who has sent me specimens and records. I will attempt to complete the identifications as soon as possible and publish a supplementary list in the spring.