Thursday, 6 June 2019

A fine, fat bumblebee - not

Byfield Pocket Park yesterday threw up a few surprises, most of which are of no interest except to nerdy dipterists and their ilk. One insect that was not a surprise was this specimen of Volucella bombylans. It is a common insect but for anyone new to entomology it can cause a bit of head scratching.

The first instinct could be to reach for a book or website dealing with bumblebees, but a closer look reveals a surprise. Bumblebees have four wings and yet this creature has only two.
Volucella bombylans, found in Byfield Pocket Park.
5 June, 2019

It is in fact a hoverfly. Many hoverflies mimic bees or wasps to some extent and this species is a superb bumblebee mimic.

When watching these creatures going about their daily business it should be clear that it is not a bumblebee. Birders often refer to the 'jizz' of a bird - something tricky to describe and yet characteristic: the posture that a bird adopts when sitting on a fence; the way in which it moves on the ground with a bouncy hop or not. The way it flicks its tail.

Hoverflies have a different jizz from a bee or a wasp but in the case of this specimen any such observations were not possible, for it was in a moribund condition when I found it and was dead by the time I had brought it home - hence the less than satisfactory photographs. But these insects are common in the garden and with practice they can soon be distinguished one from another.
The wing venation is all wrong for a bee.

Pity they don't get it right on Gardeners World, where hoverflies are often mistaken for bees.

Tony White. E-mail:

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