Oestridae

bot flies, warble flies, heel flies, gadflies

Subfamily Guides

Cuterebrinae(Robust Bot Flies)
Gasterophilinae(stomach bot flies)
Hypodermatinae(warble flies)
Oestrinae(Nose Bot Flies)

is a of parasitic flies whose larvae are obligate internal of mammals. The family includes several with distinct associations: Cuterebrinae (rodents and lagomorphs), Hypodermatinae (ungulates), Gasterophilinae (horses), and Oestrinae (sheep and other mammals). are large, robust, and often -mimics, but lack functional mouthparts and do not feed. The family has significant veterinary and medical importance due to the damage caused by developing larvae.

Hypodermatinae by (c) Trevor Van Loon, some rights reserved (CC BY), uploaded by Trevor Van Loon. Used under a CC-BY license.

Oestridae by (c) gailhampshire, some rights reserved (CC BY). Used under a CC-BY license.

Oestridae by (c) Katja Schulz, some rights reserved (CC BY). Used under a CC-BY license.

Pronunciation

How to pronounce Oestridae: /ˈiː.strɪˌdaɪ/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Distribution

Worldwide distribution, with found across North and South America, Europe, Africa, and Asia. Specific distribution varies by and species.

Life Cycle

Larvae develop as internal within mammalian , typically in subcutaneous tissue or body cavities. First instar larvae enter the host through natural orifices or wounds, then migrate to specific sites where they form warbles or cysts. Larvae feed on host fluids rather than tissue. After approximately one month, mature third instar larvae exit the host, burrow into soil, and pupate. emerge from but are short-lived and do not feed.

Behavior

are rarely encountered in the field. Females of some (e.g., Cuterebra) oviposit in where await host passage; body heat stimulates hatching. uniquely employs phoretic egg transport, laying eggs on mosquitoes or other blood-feeding flies for delivery to hosts. Adults lack functional mouthparts and focus entirely on . Some exhibit of bumble bees.

Ecological Role

Larvae function as that may influence . Some Cuterebra show relatively benign relationships with long-associated hosts, with infected mice observed to live longer than uninfected individuals in some studies. The relationship between host and parasite is attributed to long coevolutionary history.

Human Relevance

, the human bot fly, is the only known to routinely parasitize humans, occurring in Central and South America. cause myiasis and can be psychologically distressing. Veterinary species such as Hypoderma lineatum () and Oestrus ovis (sheep bot fly) cause significant economic losses through hide damage, reduced milk yield, and animal distress. Management includes treatments, mechanical removal, and strategies.