Tuesday, 3 August 2010
A hornet-mimic hoverfly
A quick check in the British Hoverflies identification guide pointed to Volucella zonaria, one of the largest and more striking British species. As other brightly coloured hoverflies, the guide drawing does not do it justice, possibly as it was made from faded, pinned specimens. This species was virtually unknown in the UK before the '40s, and then gradually established itself around the south coast, London and Bristol. Recently there are more scattered records to the north, suggesting a northern expansion, possibly linked to climate change, but nothing north of the Humber. Check its distribution map in the NBN Gateway.
Apparently it is strongly urban, thriving in parks and gardens, where adults find a broad range of flowers to feed - buddleia, hebes, brambles, ivy, hemp agrimony to name a few. As other hoverflies of the same genus, the females somehow get into wasps nests to lay their eggs, unmolested by the wasps. Once hatched, the larvae fall to the bottom of the nest where they are scavengers of the colony's debris and feed on dead wasps - and possibly live larvae - on the autumn when the nest is abandoned. The species is migrating as well, and males are territorial.
I look forward to having this around more often.