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Cuterebra emasculator
Squirrel Bot Fly
Cuterebra emasculator is a New World bot fly and obligate internal parasite of tree squirrels and chipmunks in eastern North America. First described by Asa Fitch in 1856, its larvae develop subcutaneously in hosts, creating characteristic swellings called warbles. The species name originated from a false belief that larvae consumed host testicles; research has shown this is not the case and parasitism does not reduce host fertility. Adults are rarely encountered, lack functional mouthparts, and live only a few days focused solely on reproduction.