SPERM DEPENDENCE OF FEMALE RECEPTIVITY TO REMATING IN DROSOPHILA MELANOGASTER.

Abstract

As a consequence of copulation, males of Drosophila melanogaster induce a variety of physiological and behavioral effects in the female. Egg production and oviposition are stimulated by products of the male's accessory glands (Kummer, 1960; Garcia-Bellido, 1964; Merle, 1968; Bumet et al., 1973), and female attractiveness and receptivity are both reduced following copulation. Changes in female attractiveness are mediated pheromonally. A change in pheromonal profile from courtship-eliciting to courtship-discouraging pheromones is induced during the first 3 min of (Tompkins et al., 1980; Tompkins and Hall, 1981; Venard and Jallon, 1980). The seminal fluid enzyme esterase-6 metabolizes the seminal fluid component cis-vaccenyl acetate to produce the antiaphrodisiac cis-vaccenyl alcohol (Mane et al., 1983). Behavioral effects of this metabolite on female attractiveness have been demonstrated and have been shown to be short-lived. There is a close correspondence between the time course of these behavioral effects and those first identified by Manning (1967) as the copulation effect. Manning (1962, 1967) also identified a on female receptivity which is longer lasting and causes females to remain unreceptive to male courtship. The strength of the sperm effect seems to be proportional to the number of sperm in storage (Gromko and Pyle, 1978; Gromko et al., 1984). The sperm effect is characterized behaviorally by the use of ovipositor extrusion to reject males, a behavior used only in very low frequency by virgin females (Connolly and Cook, 1973; Tompkins and Hall, 1981). The -or the sperm dependence of the return of female receptivity-is not evident when mated females are confined with second males continuously for 24 h (Newport and Gromko, 1984). In this paper we investigate the details of the sperm dependence of female receptivity within the context of an experimental design which allows females periodic interactions with second males. We also quantify the impact of sperm-dependent female receptivity on the reproductive outcome of double matings. We show that by causing females to delay remating, first males suffer very little reduction in reproductive success due to female remating.