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Botfly

A botfly is any fly in the family Oestridae.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated September 10, 2026|2 min read| Fact-checked

Botflies are parasitic flies in the family Oestridae. Their larvae develop as internal parasites of mammals, including humans. In Canada, some North American species occur, and botfly myiasis has been reported, though human cases are uncommon.

Taxonomy

Botflies are members of the fly order Diptera and the family Oestridae. The term refers to several related flies rather than a single species.

Life cycle and parasitism

Botfly larvae develop as parasites on mammals. Depending on the species, they may live in skin, tissue, nasal passages, or the digestive tract.

Human relevance

Some botflies can cause myiasis in humans, a parasitic infestation by fly larvae. Dermatobia hominis is the species most commonly associated with routine human parasitism.

Distribution and diversity

Botflies occur in multiple regions worldwide and include many species adapted to different mammal hosts. The family contains roughly 150 species.

Key facts

  • Botflies are true flies in the family Oestridae, with larvae that are internal parasites of mammals.
  • Different species affect hosts in various ways, including tissue-burrowing and gut parasitism.
  • Dermatobia hominis is the best-known species that routinely parasitizes humans.
  • Botflies are also called warble flies, heel flies, and gadflies, and adults often have a bee-like appearance.
  • In Canada, some North American species occur, and botfly myiasis has been reported but is uncommon.
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Canadian context

Botflies are relevant to Canadian readers because some North American species occur in Canada, and botfly myiasis has been reported in Canada, though human cases are uncommon.

Frequently asked questions

What is a botfly?
A botfly is a parasitic fly in the family Oestridae whose larvae develop on or inside mammals.
Are botflies dangerous to humans?
Some species can infest humans and cause myiasis, but human parasitism is not universal across the family.
Which botfly species affects humans most often?
Dermatobia hominis, the human botfly, is the species most often noted for routine human parasitism.
What do botfly larvae do?
They feed and develop inside host tissues, skin, or the digestive system, depending on the species.
What other names are used for botflies?
They are also called warble flies, heel flies, and gadflies.

References

  1. Wikipedia — https://en.wikipedia.org/wiki/Botfly
    Supports: Family Oestridae, common names, larval parasitism, and human-parasitizing species
  2. Encyclopedia.com — https://www.encyclopedia.com/plants-and-animals/animals/zoology-invertebrates/botfly
    Supports: Definition, family Oestridae, and general parasitic biology
  3. Encyclopaedia Britannica — https://www.britannica.com/animal/bot-fly
    Supports: Bot fly classification and parasitic larvae on mammals
  4. The Amateur Entomologists' Society — https://www.amentsoc.org/insects/glossary/terms/botfly/
    Supports: Approximate species count, host-parasitic life cycle, and egg-laying strategies
  5. Missouri Department of Conservation — https://mdc.mo.gov/discover-nature/field-guide/bot-flies
    Supports: Adult appearance, larval habitats, warble formation, and general biology