Saturday, July 21, 2007

A Hoverfly Sphaerophoria scripta

I am an amateur naturalist trying to learn a little about everything that lives in my garden.

On the basis that you cannot have too much of a good thing: another photo of a hoverfly! (Click on it to enlarge).

Using the beautiful colour plates in my copy of Hoverflies (Francis S. Gilbert, Richmond Publishing Co.), I'm identifying this one as a male Sphaerophoria scripta, males being longer and thinner than the females. Once again, I've failed to find a common name (anyone?).

Apparently, nine species occur in the genus Sphaerophoria in Britain. I believe the continuous yellow stripe on the side of my hoverfly's thorax (the body section after the head) indicates he's a member of the species scripta however (unless someone can tell me otherwise).

From what I've gathered about the diet of hoverflies (see here) I'm guessing mine here is enjoying his lunch of pollen or nectar. In their larval stage S.scripta eat aphids. I'd like to know what an S.scripta aphid looks like, but have not managed to find a photo though this site has extensive images and details on hoverflies as well as countless other insects.

I read that for most hoverflies mating takes only a few seconds. For S. scripta however, mating can take several hours with the male riding on the female's back in flight. Can anyone comment on what advantage S.scripta gets from being different?

As I mentioned at the end of my last posting, whether hoverflies engage in courtship rituals, and if so what form the ritual takes is, it seems, largely unknown - a good project for the patient amateur observer!