Saturday, 19 June 2010

Hoverflies and legs

Volucella bombylans is another bumblebee mimic. This is the white-tailed variety: Volucella bombylans var. plumata, which is reckoned to be a good mimic of Bombus hortorum and B. jonellus. Pity I don't have either of those on my patch.

The larvae of V. bombylans feed on detritus in the nests of wasps and bumblebees, which leads me to wonder just how important the mimicry is, since I have plenty of these hoverflies, but neither of the similar bumblebees.

This grasshopper gives me a nice lead-in to another two hoverflies. It's the Common Green Grasshopper - Omocestus viridulus:

The first of the hoverflies is Xylota segnis, which runs very quickly over leaves looking for pollen grains. The first time I saw it, it took me quite a while to realise that this fast-running, grasshopper-legged creature was, indeed, a hoverfly:

The second set of legs belongs to the hoverfly Syritta pipiens, which has inflated rear thighs that resemble pollen baskets. As a bee mimic, that would be fine, but there is no bee of a comparable size (about 8 mm. long) that collects pollen in baskets; most of the smaller bees gather pollen in abdominal or thoracic hair.

1 comment:

The Weaver of Grass said...

I think almost everyone loves the bumble bee Stuart, don't you. We frequently get them inside on our landing window but they are easy enough to rescue with a glass and a postcard. There are various nests in the front garden - easy to spot if you keep your eye on the bee.