The effect of female arrivals on mate monopolization in the yellow dung fly

Abstract

The degree of resource monopolization relates to the distribution of resources in space and time. In general, monopolization is predicted to be high when resources (food or mates) are clumped in space, dispersed in time, and predictable in space or time. Using the yellow dung fly, Scathophaga stercoraria (Diptera: Scathophagidae), we qualitatively tested a general model that predicts the distribution of mating success among competing males based on the temporal pattern of female arrivals relative to mating time and a ranking of males in priority of access to the resource (here by body size). In a laboratory experiment approximating the natural mating situation, a constant number of males of various sizes were allowed to compete for females. As predicted, mate monopolization decreased as the temporal clumping of female arrivals increased, mediated by either a decrease in the mean or an increase in the variance of female inter-arrival times, which were manipulated independently. Males appeared to adjust their behavior to variation in female arrivals in a manner consistent with the marginal value theory of Parker and associates: forcible takeovers of females were rarer, and copula durations shorter, when females arrived regularly at short intervals. Therefore, a complex interaction of variation in intrinsic characteristics affecting male resource holding potential, mating time and stochastic, extrinsic variables increasing temporal clumping of mates generally reduces the variance in mating success among competing males and thus ultimately the opportunity and intensity of sexual selection on traits influencing male success. This theory extends operational sex ratio theory at the mechanistic, behavioral level

The interrelationships between resource-holding potential, resource-value and reproductive success in territorial males: How much variation can we explain?

“…For example, population demography (e.g. male density , Borgia 1980;McLain 1992; operational sex ratio, Blanckenhorn et al 2003), individual state (e.g. energy levels, Marden and Waage 1990;Plaistow and Siva-Jothy 1996), local environmental conditions (e.g.…”

The Relationship Between Resource Control, Association with Females and Male Weapon Size in a Male Dominance Insect

“…Ideally, one should examine all three of the above said relationships concurrently in a single experimental study to control for factors known to influence a male's tenure on a resource (operational sex ratio, Blanckenhorn et al 2003; population demography: e.g. male density, Borgia 1980;McLain 1992; ecological factors: e.g.…”

Size‐Dependent Mating Success at Various Nutritional States in the Yellow Dung Fly

“…While in the non‐competitive experiment small‐line males had the highest mating success, an unusual outcome, large‐line males did best in the competitive group experiment, as is typically the case (Borgia 1980; Jann et al. 2000; Blanckenhorn et al. 2003a, b).…”

“…This 1:1 sex ratio in principle allowed each male to obtain a female, guaranteeing a high probability of copulating and hence sperm use for most males (cf. Blanckenhorn et al 2003b). However, in practice several females were not mated, e.g.…”

“…We tested individuals singly, thereby assessing mere physiological effects on an individual’s capacity to mate, as well as in a more natural competitive group situation, additionally allowing energy being spent in male–male behavioral interactions (cf. Blanckenhorn et al. 2003b).…”