Bared Bee Fly

Photo by: Bryan Reynolds

Exoprosopa fasciata

The Barred Bee Fly is a member of the Bombyliidae family, known as humbleflies or beeflies. These members are adept at pollination, since the majority of their diet consists of nectar. While adults frequent flowers, larvae are fed paralyzed insects— therefore, they’re known as parasitoids. Aside from its pollination, this species is prized for its ability to cut down insect populations, such as grasshoppers and caterpillars (using them as food for larvae). However, this family also lays eggs in bee burrows, where its own larvae can feed on the stored pollen of bees.

A variety of morphological features can help the average naturalist identify the family. In length, the smallest recorded specimen was 2 millimeters long, but wingspans of up to 40 millimeters have been found. Another distinguishing feature of bee flies is their tendency to “fold their wings back” in repose. The barred bee fly, true to its name, has an abdomen divided between yellow and black bands, along with a black or dusky thorax, and a black head. All threeof these segments are covered in wiry, dense hair. The eyes of this species have been described as a dull, muted orange. Like other Bombyliidae, the Barred Bee Fly has a proboscis, though their proboscis is straight (a characteristic shared by all bee flies), and cannot be retracted. It’s theorized that bee flies exhibit this unique coloration as a form of batesian mimicry, where a nonlethal species imitates a dangerous species to deter predation.

The largest members of this species are usually found in temperate climate zones, but they are common in the tropics. As a rule, barred bee flies enjoy open, sunny environments so they may find nectar and prey.

Written by: Robert Gibson, an undergraduate Environmental Studies student at the University of Oklahoma