Thanks to a reader, one of the pictures in my gallery has been positively identified as a Long-Tailed Dance Fly (Empididae, Rhamphomyia longicauda).

I had been out hiking after a rain storm and this particular fly was sipping up the water that had pooled on the leaves of some shrubs. These flies have some very neat mating rituals. Females sworm together in groups called mating leks. Males come to the leks with a nuptual gift (food) in exchange for being able to mate. Males have a preference to mate with females that have larger abdomens. Entomologists think that they prefer larger-abdomen females because the more swollen they are, the more mature and ready the eggs will be, and the better the chance that he will sire the offspring.

Females are tricky though (of course) and have a way of fooling the males into mating with them and getting a free meal. Females puff up their abdomens so they appear more swollen than they actually are. I couldn’t find a nice picture (really any picture) on the web of the puffed abdomen to link to, so if you have access to this Nature article you can click on the link and read more. The picture below is taken from that article (Tromans, A. 2000. Entomology: Love is Not Puffed Up. Nature 404:138) in case you can’t access the article.

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