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Flies That Burrow in Animals

There are thousands of species from the order Diptera that have been given the common name 'flies.' Members of this order have a complex life cycle made up of four parts: egg, larva, pupa and adult. During each of these life stages they play an intricate role in the ecosystems in which they exist. According to The Merck Veterinary Manual, flies can be helpful because they work to decompose the bodies of dead animals in the environment. However, some types of flies use animals long before the animal has died by burrowing into them.

  1. Bot Flies

    • Bot flies come from the family Cuterebridae. Other common names include Torsalo or Dermatobia hominis. Their eggs get to the host's body by another insect vector, like a mosquito, and then the larva burrows into the skin. There, the larvae develop and form a tumor called a warble in the subdermal zone of the host. They leave the host's skin when they're about to become pupa.

    Screw Worm Flies

    • The Cochliomyia hominivorax lays 200 to 400 eggs in the exposed flesh of warm-blooded animals. Like the Bot flies, the larva hatch and burrow into the skin of the host. The name screw worm comes from the fact that the larvae are likely to burrow deeper into the host if they are disturbed before they resurface to become pupa. If the screw-worm goes too deep or if there are too many in one host, the host can be severely injured or killed. They are found mostly in Central and South America and in certain Caribbean islands. Another screw worm is Chrysomyia bezziana. It is found in Africa, India, and Southeast Asia. They lay their 150 to 500 eggs at the edge of wounds or near body orifices of warm-blooded animals. The larva burrows into the open flesh so that its posterior end is visible.

    Grey Flesh Flies

    • The Wohlfahrtia vigil, or grey flesh fly, is found in the Northern United States and Southern Canada. The fly deposits its larvae, not eggs, on the skin of the host's body. The larva then burrows into the flesh where it grows for about two weeks then remerges to develop into the pupa stage.

    African Tumba Flies

    • The Cordylobia anthropophaga is found primarily in sub-Saharan Africa. Some other common names for this fly are mango fly, skin maggot fly, Ver du Cayor and worms of Cayor. During their larval stage in the host's body, they expose their postieror end like the grey flesh fly or the Chrysomyia bezziana.

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