The female reproductive tract is where competition between the sperm of different males
takes place, aided and abetted by the female herself. Intense postcopulatory sexual …

The outcome of sperm competition is mediated largely by the relative numbers of sperm from
competing males. However, substantial variation in features of sperm morphology and …

Females of many species mate with multiple males, thereby inciting competition among
ejaculates from rival males for fertilization. In response to increasing sperm competition …

Fishes show one of the widest ranges of sperm competition intensity of any animal group.
Here we present a comparative study whose aim is to investigate the effect of relative …

Females frequently mate with several males, whose sperm then compete to fertilize
available ova. Sperm competition represents a potent selective force that is expected to …

Publisher Summary This chapter reviews the current knowledge of variation in sperm
morphology over several levels of biological organization: variation within males (both within …

Fish exhibit an enormous variety of reproductive patterns. There is external and internal
fertilization, simultaneous and sequential hermaphroditism as well as gonochorism, and an …

Models of sexual selection typically assume a cost to the production and maintenance of
sexually selected traits. However, within a population, individuals of high phenotypic quality …

This paper investigates mechanisms of sperm competition by comparing reproductive
characteristics across 74 butterfly species. Testis size scales with body size and, after …

Females of all species belonging to the family Drosophilidae have two kinds of sperm‐
storage organs: paired spherical spermathecae and a single elongate tubular seminal …