Worcestershire Record No. 27 November 2009 p. 22

Geoff Trevis

“The Times They are A’changin’” has been the subject of two meetings – the Worcestershire Recorders Annual Meeting in March and the Wyre Forest Study Group Entomology Day in November. The idea was to review the changes to wildlife in the county consequent largely on climate change but taking account of other factors that may be affecting the populations and distribution of species. Two groups which may be able to shed light on such changes are the bumblebees and social wasps.

Bumblebees are particularly interesting since closely related species have shown marked differences in their response to environmental changes in recent years. Some appear to be doing fairly well and are maintaining healthy populations e.g. the White-tailed Bumblebee Bombus lucorum, the Common Carder Bee B. pascuorum, and the Red-tailed Bumblebee B. lapdarius. Others have shown rapid declines in numbers such that the Short-haired Bumblebee B. subterraneus is now extinct in Britain whilst the Red-shanked Carder Bee B. ruderarius and the Shrill Carder Bee B. sylvarum have declined so far as to warrant protection through national Biodiversity Action Plans. Conversely, a few species are increasing. The once rare Large Garden Bumblebee B. ruderatus is turning up more and more frequently. We have several records in Worcestershire. Perhaps most interesting of all is the common Buff-tailed Bumblebee B. terrestris which is being recorded throughout the year and may be moving towards continuous broods like the honey bee instead of the annual nest cycle with only the queens surviving the winter to found a new colony each year.

Changes to social wasps are less obvious though two species new to Britain were record in the mid to late 1980’s, Dolichovespula media and D. saxonica, and there is evidence that the Hornet Vespa crabro has become significantly more common though it has shown little tendency to extend its range. It is also possible that we may expect a new genus of wasp to become more widely established, this being Polistes dominulus.

The great thing about bumblebees and social wasps is that with a little effort they may generally be identified in the field using only a hand lens and suitable collecting tube and it is not necessary to kill them for microscopic examination. Queen bumblebees are more easily identified than workers. We are hoping to set up a county Bumblebee and Wasp Recording Group to assist with monitoring changes in abundance of species and in their flight period. Data will be of interest locally and will be submitted to the national recording schemes. If you are interested in being a founder member of this group please contact me via e-mail, geoff.trevis@btinternet.com, or drop me a line at 14, Old Coach Road, Droitwich Spa, Worcs., WR9 8BB. Harry Green and I will give as much help as possible with honing your skills at identification so beginners with these groups will be very welcome.