Asiloidea

Pronunciation

How to pronounce Asiloidea: //ˌæ.sɪˈlɔɪ.di.ə//

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Summary

The Asiloidea is a diverse superfamily of flies within the order Diptera, characterized by notable morphological traits and cosmopolitan distribution. It includes families such as Bombyliidae and Asilidae, exhibiting various ecological roles from predation to parasitism.

Physical Characteristics

Large and showy flies; antennae with no more than 4 flagellomeres; leg empodium usually setiform or absent; wing with cell cup elongate and vein CuA2 ending freely on the wing margin or meeting with vein A1 at or near the wing margin. In Mydidae, Apioceridae, and Asilidae, the head is at least slightly concave between the eyes and the ocelli; dichoptic in both sexes. In Therevidae, Apsilocephalidae, and Scenopinidae, males are usually holoptic.

Identification Tips

Look for the number of flagellomeres (maximum of 4) and the structure of the wings, especially the elongate cell cup. The head structure and eye configuration (dichoptic or holoptic) can also aid in identification.

Habitat

Greatest diversity in arid, sandy habitats; adults typically visit flowers, while larvae often inhabit substrates and are predatory.

Distribution

Cosmopolitan distribution, occurring worldwide; some families are more restricted in distribution, e.g., Evocoidae only found in Chile.

Diet

Adults usually feed on nectar from flowers; larvae are typically predatory, although some (like Bombyliidae) are parasitoids.

Life Cycle

Known larvae exhibit posterior spiracles on the penultimate abdominal segment; most larvae of asiloids remain unknown. The typical larval cranium is modified into a hinged metacephalic rod (except in Bombyliidae and Hilarimorphidae).

Ecosystem Role

Predators of other insects; some families function as parasitoids.

Evolution

The ancestral lifestyle for asiloid larvae is believed to be parasitoidism, later replaced by predation in families except Bombyliidae. The lineage diverged from other Asiloidea about 150 million years ago in the Jurassic, with significant divergences occurring in the Cretaceous.

Similar Taxa

• Empidoidea
• Cyclorrhapha

Misconceptions

The superfamily is not clearly monophyletic; its familial relationships are complex.

Tags

• Diptera
• Asiloidea
• insects
• predators
• parasitoids