It is unknown why females mate with multiple males when mating is frequently costly and a single copulation often provides enough sperm to fertilize all a female's eggs. One possibility is that remating increases the fitness of offspring, because fertilization success is biased toward the sperm of high-fitness males. We show that female Drosophila… (More)
Males and females share a genome and express many shared phenotypic traits, which are often selected in opposite directions. This generates intralocus sexual conflict that may constrain trait evolution by preventing the sexes from reaching their optimal phenotype. Furthermore, if present across multiple loci, intralocus sexual conflict can result in a… (More)
Rapid and divergent evolution of male genital morphology is a conspicuous and general pattern across internally fertilizing animals. Rapid genital evolution is thought to be the result of sexual selection, and the role of natural selection in genital evolution remains controversial. However, natural and sexual selection are believed to act antagonistically… (More)
Individuals in many animal species exhibit 'personality,' consistent differences in behaviour across time, situations and/or contexts. Previous work has revealed a negative genetic correlation between intensity of tonic immobility and walking activity levels in the confused flour beetle, Tribolium confusum, thus suggesting these beetles exhibit personality… (More)
Mating system variation is profound in animals. In insects, female willingness to remate varies from mating with hundreds of males (extreme polyandry) to never remating (monandry). This variation in female behaviour is predicted to affect the pattern of selection on males, with intense pre-copulatory sexual selection under monandry compared to a mix of pre-… (More)
Males in many taxa are known to exhibit behavioural plasticity in response to the perceived intensity of sperm competition, reflected in Drosophila melanogaster by increased copulation duration following prior exposure to a rival. We tested the prediction that males do not adjust their copulation effort in response to the presence of a competitor in… (More)
Selfish genetic elements (SGEs) that spread by manipulating spermatogenesis often have highly deleterious effects on males that carry them. Females that mate with male carriers of SGEs can also suffer significant costs: they receive fewer and poorer-quality sperm, their offspring will inherit the deleterious allele, and the sex ratio of their offspring will… (More)
Sperm from Drosophila simulans that carry a sex-ratio distorter is preferentially lost from females' sperm-storage organs. This suggests that sperm dumping is a major factor affecting sperm competition in this species, and may have evolved in response to sex-ratio distorters.
The rapid, divergent evolution of genitalia is a general trend in animals and likely influenced by sexual selection. Contrary to previous ideas, an intriguing new study suggests that sexual selection by sexual conflict can promote the evolution of both male and female genitalia.
It is now generally recognized that it is necessary to examine how sexual selection operates across the lifespan of a male, in order to understand the total sexual selection in action. However, less attention has been paid to the fact that selection pressures can change in response to varying environmental conditions. Here, we examine male allocation to… (More)