Polyandrous females discriminate against previous mates

TLDR

In polyandrous species, females typically engage in sequential mate choice, yet how they respond to solicitation by previous mates has been largely unexplored. This study examined whether once‑mated Cordylochernes scorpioides females differ in receptivity to their first mate versus a new male after short (1.5 hr) or long (48 hr) intervals. Researchers presented once‑mated females with either their first mate or a novel male after 1.5 hr or 48 hr intervals and recorded receptivity. Females remained receptive to new males regardless of interval, but were consistently unreceptive to their first mate after 1.5 hr, a pattern that disappeared after 48 hr, indicating female discrimination against previous mates independent of male traits.

Abstract

In most animal species, particularly those in which females engage in polyandry, mate choice is a sequential process in which a female must choose to mate or not to mate with each male encountered. Although a number of theoretical and empirical investigations have examined the effects of sequential mate choice on the operation of sexual selection, how females respond to solicitation by previous mates has received little attention. Here, we report the results of a study carried out on the polyandrous pseudoscorpion, Cordylochernes scorpioides , that assessed the sexual receptivity of once-mated females presented after a lapse of 1.5 hr or 48 hr with either their first mate or a different male. Females exhibited a high level of receptivity to new males, irrespective of intermating interval. By contrast, time between matings exerted a strong effect on female receptivity to previous mates. After a lapse of 48 hr, females did not differ significantly in their receptivity toward previous mates and different males, whereas at 1.5 hr after first mating, females were almost invariably unreceptive to males from whom they had previously accepted sperm. This result could not be attributed to male size or mating experience or to male sexual receptivity. Indeed, males were as willing to transfer sperm to a previous mate as they were to a new female. This difference between males and females in their propensity to remate with the same individual may reflect a conflict between the sexes, with males seeking to minimize postcopulatory sexual selection and females actively keeping open the opportunity for sperm competition and female choice of sperm by discriminating against previous mates.