Hymenoptera - Summer 2001

By Geoff Trevis

I have had a steady but small flow of records during the year, most of which, as expected, add to the existing records on known sites. The major source of new material has been the recording days and the species lists for these appear separately. The outbreak of foot and mouth disease of course curtailed activity and reduced the amount of field work undertaken and limited the sites that could be visited.

I had hoped to add significantly to the records of the common social wasps and bumblebees but the response to my plea for records was disappointingly small and very few tetrads have been filled in. Nonetheless, the records that did come in were of considerable interest. Perhaps the most important came from Martin Skirrow who found nests of the two latest social wasp additions to the British list - Dolichovespula media and D. saxonica - at Hanley Swan. Both species were originally found in the south east of England and have been spreading slowly north west. There have been only two or three records of D.media in Worcestershire (see a report by Kevin McGee elsewhere in this newsletter) and this is the first record of D. saxonica for the county (unless anybody can tell me differently).

A late record (see also below) came from a Mr. C.G. Harrison, a new member of the BRC, who has had Hornets Vespa crabro visiting his house and garden at Sale Green for the last two or three years. Once again, could I make a plea for bumblebee and social wasp records or specimens.

It has been a fairly good year for bumblebees and the common garden species, Bombus terrestris, B. leucorum, B. lapidarius, B. pascuorum, B. hortorum, B. pratorum and B.ruderarius have all been seen. The only significant new record was a queen Bombus (Psithyrus) sylvestris on the capped tip at Penny Hill Quarry, near Martley. There have been tantalising sightings (only one of which was validated) in previous years of the rare B. ruderatus and we will continue to look out for this species in coming years.

John Meiklejohn has been looking at a site on the Kemerton Estate which appears to be particularly rich in hymenoptera and we will hopefully be able to investigate further next year. Both Michael Archer and Steven Falk have commented that Bredon Hill and its surroundings are seriously under recorded and could prove to be of national importance. Certainly John's capture of Andrena flavipes at Kemerton supports this view as Michael Archer, who validated the record, noted that A. flavipes here must be at or beyond the northern boundary of its known distribution. What we do not know is whether this species has been here for some time undetected or whether we a seeing a northern expansion of range in response of global warming.

Ants have been having something of a revival with some of our invertebrate recorders and as noted previously, the shining black ant, Lasius fuliginosus, was found during tetrad recording on road side verges. L. brunneus, a species considered nationally scarce, continues to be found regularly, showing Worcestershire (and probably the Severn valley generally) to be of particular importance for its conservation. It is a tree dwelling species that seems to prefer mature but isolated trees in hedgerows and woodland boundaries. The latest find was on the recording day at Devil's Spittleful.

I have been looking, casually, for an ant species, Formicoxenus nitidulus, so far unrecorded in Worcestershire. This is a small ant that lives in the nests of the much larger wood ants Formica rufa in southern England). The wood ants seem to get no benefit from the presence of F. nitidulus and indeed are occasionally seen to attack it. It is difficult to find as its nest is deep inside the wood ant nest but the caste most often seen is wingless males as these patrol the surface of the wood ant nest looking for unfertilised winged females. Peak emergence is in October but if you are looking at a wood ant nest at any time do look out for a much smaller species. I would be very glad to hear about it.

Editor's Footnote:

A Big Hornet's Nest

I happened to be at the Worcestershire Wildlife Trust office when Keith Turner phoned. Would anyone be interested in a hornet's nest 3x2 feet in a neighbour's roof loft! How could I resist! A few days later John Meiklejohn and I went down to Staunton on the Gloucestershire border and collected the nest (approximately 2 feet diameter in the cool light of day!). It was a very beautiful structure, much warmer yellowish in colour than a grey of a wasps' nest and patterned with lines each laid down by a hornet from chewed wood. Hornets take a much wider range of vegetable material than wasps (I saw one green streak - perhaps painted wood) and the nest is more fragile. Harry Green