Sexual Aggressiveness of Male Screw-Worm Flies Affected by Laboratory Rearing1

Abstract

In tests of sexual aggressiveness, males from 2 strains of screw-worm flies, Cochliomyia hominivorax (Coquerel), that were reared in the laboratory for 5 and 15 generations did not harass females as vigorously as males from 2 strains that were reared in the laboratory for 41 and >100 generations. Intermediate ranking was assigned 2 strains reared in the laboratory for 69 and 26 generations. Considering the mobility of this species and the localities of the original collections, it is believed that the observed differences in male mating activity are probably an indication of laboratory adaptation rather than physiological differences in the wild populations from which the strains were derived.