Female multiple mating for fertility assurance in red flour beetles (Tribolium castaneum)

Abstract

The costs of mating with multiple partners include expenditure of energy and time and a reduction in lifespan, but females of many taxa mate with several different partners shortly after their first copulation. Often it is not clear what females gain from this behaviour. In this study, we used the red flour beetle (Tribolium castaneum Herbst, 1797) to test the hypothesis that females mate with multiple males for fertility assurance because the first copulation often does not lead to offspring production. We found that the probability of producing offspring, as measured by the proportion of females that produced offspring, was not affected by multiple mating when females were mated to virgin partners. However, when females were mated to nonvirgin partners, multiple mating led to an increased probability of producing offspring. To establish the mechanism through which multiple mating enhanced the probability of producing offspring, we further investigated whether this result was observed because multiple mating provided genetically compatible sperm or because it provided sufficient sperm. Viability of larvae from multiply mated females was higher than that of larvae from singly mated females, but the total number of adult offspring produced was not significantly different between the two groups. The capacity of males to inseminate females decreased in successive matings after the initial copulation, suggesting that ineffective copulations between virgin females and nonvirgin males are likely due to male sperm depletion. Therefore, mating with multiple males increased the probability that females would produce offspring and served as fertility assurance.

Inter‐population variation in multiple paternity and reproductive skew in the guppy

“…Such a mechanism has been invoked to explain multiple mating patterns in several species (e.g. Kamimura 2003; Pai et al . 2005; Uller & Olsson 2005), and it is consistent with the correlation between brood size and number of sires that we uncovered in guppies (Fig.…”

Evaluating Cryptic Female Choice in Highly Promiscuous Tribolium Beetles

“…These include higher larval viability of offspring (Pai et al 2005; but see Pai and Yan 2003b), higher insemination success of sons (Pai and Yan 2002b), and higher egg viability in grand-offspring (Pai and Yan 2002b). A recent study has also found significant father-son heritability for sperm offense, reproductive success, and longevity (Lewis et al 2012), suggesting that females could benefit from mate choice.…”

“…Among the benefits identified for flour beetles are increased female fecundity (Park 1933;Lewis and Austad 1994) and the probability of successful insemination (Pai et al 2005). Notably, some of these may come from higher ejaculate quantities transferred, because females who mate repeatedly with the same male also produce more offspring (Nilsson et al 2002).…”

Multiple Paternity Benefits Female Marbled Salamanders by Increasing Survival of Progeny to Metamorphosis

“…The former is not controversial, and explanations as simple as females needing additional sperm (i.e., the fertility assurance hypothesis) can explain the evolution of polyandry (Pai et al. ; Briefer et al. ; Worthington & Kelly ).…”