Monday, September 03, 2007

Knapweed and Rhingia hoverfly

The knapweed plants (Centaurea nigra) have been flowering all through August and attract many insects like this hoverfly Rhingia rostrata on the left hand side of the picture. Once thought to quite a rarity, it is common in our area and has a strong preference for red and purple flowers.

So far as I know its early stages remain undiscovered, though a sister species, Rhingia campestris, has larvae that live in cow dung. Since cows are now so often treated with Ivermectin, and since R. campestris seems much scarcer than it used to be, R. rostrata may breed elsewhere: badger dung has been suggested as a candidate.

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