Empis borealis (original) (raw)

Empis borealis is a species of dance flies in the fly family Empididae. It is found in most of Europe, except the Balkan Peninsula, the Baltic Region and the Iberian Peninsula. The brown wings of the female are very broad, while the male fly’s wings are narrower. This particular species of fly exhibits sex-role reversal in its mating process, with female flies aggregating in swarms to compete for male choice. Female fly swarms change their flying behavior in the presence of males, who present nuptial gifts to females before mating.