Biology of robber flies (a natural enemy of field crop pests)

There are 29 species of robber flies (Family: Asilidae) in the UK, of which two species are important for biocontrol. 

Adults are of variable size, 3–50 mm long (typically 9–15 mm long) and vary in shape, from long and slender to short and stout. Likewise, colourings are variable, sometimes with yellow or orange markings on the body, like the markings of wasps and bees (warning signs). They are relatively rare on farmland.

The number of generations per year varies from one to several, depending on the species.

Larvae predate the larvae of other insects, either in the soil or in decaying wood. Adults are agile flyers, capable of catching other insects on the wing, and spiders. They are found in most types of uncropped land on farmland. Two species are considered important for biocontrol.

Unknown.

Robber flies favour open, sunny habitats, comprising grassland and shrubs or hedgerows.