Entomology (Study of Bugs)/Mouse bot fly


How large are the larva of the mouse bot fly. Can they infect rats as well? I found a dead rat on my porch this morning (cat kill I believe) with the side of it face neck and shoulder "chewed" on, that could not have been done by a bot fly larva, could it. I guess I forgot to mention there was a larva looking creature a few inches from the rat that looked very much like the picture I just saw sent from another person. This one was at least an inch though. Sorry no picture available. My husband accidentally let it get away...now I think I have to move because I don't know if can stay there knowing there is such a creepy creature crawling around my home! I like the old saying ignorance is bliss.

Dear Angela - A fully grown larva of a rodent bot fly can be an inch or so long, and quite plump. They live just under the skin of their host and breathe through a small hole they keep open in the host's skin. When mature, they enlarge this hole just enough so that they can squeeze out - see http://tinyurl.com/ksn7pqd for an image. They are not capable of causing any kind of a chewing wound. Also, a larva that has left its host, voluntarily or otherwise, is not capable of of infesting any other host - it will either undergo pupation or die. The adult fly (see http://tinyurl.com/l3kguos for an image) lacks functional mouthparts and cannot feed or bite, living only long enough to find a mate and reproduce.
Hope this helps,

Entomology (Study of Bugs)

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Ed Saugstad


Will accept most questions in general entomology, including those related to medical entomology, taxonomy, ecology, arthropod surveillance, and pest management. If you are requesting a 'mystery bug' identification, PLEASE either attach an image to your question, or post an image on a web page (such as Flickr) so that I can look at it, as verbal descriptions frequently are insufficient for a definitive identification.


21 years in the U.S. Army as a medical entomologist; duties varied from surveillance of pest populations (including mosquitoes, cockroaches, ticks, and stored products pests) to conducting research on mosquito-virus ecological relationships and mosquito faunal studies. Ten years as a civilian analyst for the Department of Defense, primarily on distribution of vector-borne diseases worldwide. Limited experience on surveillance of agricultural insects in North Dakota and Indiana.

Entomological Society of America, West Virginia Entomological Society, Society for Vector Ecology, National Speleological Society, West Virginia Association for Cave Studies.

American Journal of Public Health, Contributions of the American Entomological Institute, Japanese Journal of Sanitary Zoology, Journal of Economic Entomology, Mosquito News, and Mosquito Systematics.

B.S. in entomology from North Dakota State University in 1963, M.S. in entomology from Purdue University in 1967.

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