Robber Flies
Asilidae
Classification
Pronunciation
How to pronounce Asilidae: //əˈsaɪlɪdiː//
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Images
Summary
The Asilidae family, or robber flies, are a diverse group of predatory flies characterized by their robust bodies, unique mouthparts for piercing and sucking, and distinctive morphology, including three ocelli. They are effective predators of various insects, with an ecological role in controlling their populations.
Physical Characteristics
Typically 5-30 mm in length, with a more common size between 9-15 mm. Robber flies have stout, spiny legs, a short stout proboscis, and three simple eyes in a depression on the top of their head. Their integument is covered with thick hair, and they exhibit a dense moustache of stiff bristles called the mystax.
Identification Tips
Look for robust, bristly bodies, short stout proboscis, and the presence of the mystax. The three ocelli are arranged in a characteristic depression formed by the elevation of the compound eyes, which is a distinctive feature. The contrasting coloration can also be indicative of species differentiation.
Habitat
Open, sunny, and dry habitats like savannahs, steppe, forests steppe, semideserts, and shrublands. They favor scattered vegetation or bare ground.
Distribution
Cosmopolitan, occurring in all zoogeographical regions except Antarctica. Highest biodiversity in warm, tropical, subtropical, and arid regions.
Diet
Predominantly insectivorous, feeding on a broad range of prey including flies, beetles, butterflies, moths, bees, ants, dragonflies, and other insects. They inject saliva with neurotoxins and proteolytic enzymes to immobilize and digest their prey.
Life Cycle
Life cycle typically lasts 1-3 years, including four larval instars followed by pupation. Most species overwinter as pupae, emerging as adults in spring.
Reproduction
Females lay eggs in the soil, on plants, or in crevices within wood. Egg-laying habits depend on the species, with some laying eggs in masses covered with a protective coating.
Predators
Some species may be preyed upon by larger predatory insects, birds, or mammals.
Ecosystem Role
They play an important role in ecological stability by acting as predators of small arthropods, helping to regulate insect populations.
Health Concerns
Some species can deliver painful bites to humans if handled carelessly, and they are capable of defending themselves against predators.
Evolution
The family Asilidae has been recognized since 1802 by Latreille, with ongoing research into their taxonomy and phylogenetic relationships resulting in the identification of numerous subfamilies over the years.
Similar Taxa
Misconceptions
Sometimes confused with the related family Therevidae, which lack the piercing, predatory mouthparts characteristic of robber flies.
Tags
- Insects
- Diptera
- Predators
- Ecology
- Biodiversity