It feeds at first on the pollen and nectar supplied by the cells owner until its first moult. The second stage larva is very different, looking far more like a maggot, and it feeds on the larva of the bee or wasp with whose cell it has been sharing peacefully up until this time. After it has finished devouring the helpless bee or wasp larva the Bee-fly larva pupates in the soil from where it emerges next Spring, the adults in comparison with their carnivorous larva feed entirely on nectar. Dance flies look and act a lot like Robber-flies, from which they can be distinguished by their less bulging eyes and the lack of the trough between their eyes, and the fact that their larva, as well as their adults, are carnivorous. They are called Dance flies because members of the genus Hilara can often be seen flying low over the water in a twisting spiralling manner that to our eyes looks much like a dance.
Dance flies are also of interest because of their courtship.
Because of their predatory nature the males often feel it is advisable to offer the female a gift of food to keep her occupied while he is mating with her. In the least complicated species the male simply offers the female an insect he has caught, in more advanced species the male wraps the gift in a ball of cotton spun from special glands in his front legs, and in some decadent species the male offers the female an empty ball of silk safe in knowledge he will have done the deed and escaped before she catches on to his deception. These pages are here free for you to use, I would like to keep them that way, however making and running this site, and the other sites I am currently making or have made, on Birds, Mammals, Insects and Fish and Bacteria costs money. There are simple ways you can help. By using the search engines here you make me 2 or 3 cents a time, by buying goods from Discovery Store you also help.