FACTORS INDUCING MATED BEHAVIOR IN FEMALE HESSIAN FLIES (DIPTERA, CECIDOMYIIDAE)

When depleted of seminal fluids after serial matings to a group of females, male Hessian flies were unable to induce the permanent cessation of calling and sexual receptivity and the onset of oviposition in previously unmated females. Females mated by depleted males resumed calling behavior within almost-equal-to 22 min of mating and did not deposit eggs on the day of mating. Females that resumed calling behavior were quickly mated again when exposed to other males. However, mating with a depleted male did induce females to become temporarily refractory to subsequent mating attempts. Refractory females rejected males by wing-flapping, abdomen arching, walking, or flying off. The factor that permanently induced females to stop calling, remain unreceptive, and begin ovipositing was contained within the male reproductive tract. Virgin females injected with an extract of male abdomens did not resume calling, rejected mating attempts, and deposited a large number of eggs within several hours. Females injected with saline or an extract of male abdomens minus the reproductive tract resumed calling behavior, were receptive to courting males, and deposited few eggs. The mechanical stimulus associated with the act of mating and the chemical stimulus passed to the female during copulation seemed to act sequentially. Females initially responded to a mechanical stimulus by not calling and rejecting mating attempts by males, then responded to a chemical stimulus by continuing to show those behaviors and by ovipositing.