A "Fly Factor" in Attractant Studies

Abstract

A series of tests with a standard cornmeal-mush bait and wild populations of the house-fly, Musca domestica. demonstrated that baits previously visited by flies were more attractive to other flies than those similarly exposed but not so visited. Factors such as time of protected exposure, relative positions of samples, mixing of protected and open ( and thus previously-visited) samples, rotation of samples through various angles, etc., contributed to the single conclusion that an olfactory factor is left by flies visiting a bait, making that bait more attractive to other flies. Such a factor, soluble in ethanol, has been extracted from bodies of flies.