Xanthogramma citrofasciatum

Mad dogs and Englishwomen: I walked three miles along a disused railway line today, in searing mid-day heat, in search of a Grizzled Skipper. I found one too, but it was much less impressed with me than I was with it, and wouldn't let me anywhere near it - so all I have is record shots. I came back home extremely pink and cross, with a few shots of other things that were, I felt, much less worth frying for than a Grizzled Skipper.

However....

"Nice," said the Hoverfly Man, on seeing this chunky little fly. It's called Xanthogramma citrofasciatum, which is quite a handle for something so small to carry around. Its common name is the Barred Ant-Hill Hoverfly; not because it's been barred from every ant hill in town, however much I'd like that to be true, but because of its smart yellow stripes, and the fact that it's a kind of cleptoparasite, I suppose, of the Yellow Meadow Ant. Yellow Meadow Ants breed aphids in their underground nest, and feed on the aphid honeydew; and the larvae of Xanthogramma citrofasciatum develop in the ant nest and eat the aphids.

This whole situation has me shaking my head in bemusement. The ants' farming strategy is interesting enough, but the fact that this hoverfly species has inserted itself into the ant story is even stranger. I'd like to know more about it: how does the hoverfly get its eggs into the ant nest, what do the ants think about the hoverfly larvae eating their livestock, and how and at what stage do the larvae get themselves back to the outside world? I've tried to find out, but with no success so far; I'll probably be puzzling over it half the night.

I'll have another try for a Grizzled Skipper within the next few days, but Xanthogramma citrofasciatum turned out to be reasonable compensation in the end.