Thick-headed Flies

Conopidae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Diptera
Superfamily: Sciomyzoidea
Family: Conopidae

Pronunciation

How to pronounce Conopidae: //koʊˈnɒpɪˌdiː//

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Summary

The Conopidae, or thick-headed flies, are a family of flies characterized by their mimicry of wasps and bees, internal parasitism during the larval stage, and presence on flowers as adults feeding on nectar. They exhibit a unique reproductive strategy, laying eggs on unsuspecting hosts in flight.

Physical Characteristics

Medium-sized, blackish or brownish flies, 4-18 mm in length, often lustrous with black and yellow or reddish brown markings. They have a long, slender, geniculate proboscis and a broad head. The genitalia are conspicuous, particularly in females. Ocelli may be present or absent, and the wing is usually clear with possible dark markings along the costa.

Identification Tips

Distinguished from syrphids by their long, slender proboscis bent forward from the base and the absence of a spurious vein (except in Physoconops).

Habitat

Adults are usually found on flowers; larvae are endoparasites of various hosts including wasps, bees, ants, crickets, cockroaches, and some Diptera.

Distribution

Worldwide except poles and many Pacific islands; approximately 70 species found in North America.

Diet

Adults take nectar from flowers; larvae are endoparasites of aculeate Hymenoptera and other insects.

Life Cycle

The larvae develop internally as parasites within their hosts. Most conopids are known to aggressively intercept hosts in flight to deposit their eggs.

Reproduction

Females oviposit on hosts while in flight, using complex structures to pry open the host's exoskeleton. The genus Stylogaster has eggs with a barbed tip for penetration and attachment to the host.

Ecosystem Role

Conopids play a role in controlling populations of their host organisms, some of which are important pollinators, and may influence flower visitation patterns due to adult feeding behavior.

Economic Impact

Certain species have minor economic importance as parasites of honey bees, affecting bee populations.