• Odd critter ID


    My son found the unusual critter in this photo and video (https://bit.ly/3BvxAWt) on his driveway in Chesterland. What is it?

    Naturalist's Response

    Your photo was identified by iNaturalist as an immature mouse bot fly. Bot fly larvae of various species, also known as warbles, grow in wild mammals but can also parasitize domestic animals and occasionally humans. A full-size larva, like the one in the photo, burrows into the soil and pupates, emerging in one to 11 months as an adult fly.

    Adults do not feed, but the fly lays eggs, often in animal burrows, that hatch into tiny larvae that are picked up by mammal fur, then enter a host through the nose, mouth or anus. Once inside the host, the larva migrates through the body to a place below the skin, appearing as a small lump with a breathing hole for the larva. The larva continues to feed and grow until it leaves the host, like the one photographed, to find its way underground until conditions, like temperature, are right for it to emerge as an adult fly.

    These links will provide more information:
    Rodent Bot Fly Larvae | Mountain Lake Biological Station, U.Va. (virginia.edu)
    Mouse bot fly (Cuterebra fontinella) – Seashore to Forest Floor

    -Naturalist Dottie Drockton