Eumerus paulae
Of the more than 120 families of Diptera (flies) two stand out for their attraction to collectors, the Syrphidae (flower or hover flies) and the Asilidae (robber flies). Both families are speciose with the latest totals of African species at ca. 565 Syrphidae and 1455 Asilidae. Asilids are obligate predators of arthropods, mostly of insects but also spiders. They are equipped with stiletto-like mouthparts for impaling their prey, piercing its integument and drinking the blood (hemolymph) of its paralyzed victim. Some species are very large (among the largest Diptera) and these are truly fearsome insects. Their common name doesn't do them justice. The only thing they steal is the life of their prey.
Compared with the robber flies, hover flies are relatively pacific, although one large group are predaceous as larvae on aphids, in some cases efficient enough to be used in biological control of aphids. And if this was not enough, the Syrphidae as a whole are considered the most important pollinators, after the bees. Syrphids are truly farmers' friends. The species featured here is a member of the genus Eumerus, probably Eumerus paulae. Eumerus is an old world genus, common in Africa, Asia and Europe. Although not native to the new world, some species are invasive, having been introduced into the Americas. While many flower flies with their contrasting black and yellow bands mimic bees and wasps, E. paulae does not. Instead, it is covered with long silvery-white hairs. What role this beautiful vestiture plays in the species' biology is not known.
Credits: Dr Robert Copeland, icipe