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

In many animal species, males may exhibit one of several discrete, alternative ways of
obtaining fertilisations, known as alternative reproductive tactics (ARTs). Males exhibiting …

Ongoing anthropogenic climate change has increased attention on the ecological and
evolutionary consequences of thermal variation. Most research in this field has focused on …

Spermatozoa are among the most diversified cells in the animal kingdom, but the underlying
evolutionary forces affecting intraspecific variation in sperm morphology are poorly …

Energy saving mechanisms are ubiquitous in nature. Aerodynamic and hydrodynamic
drafting, vortice uplift, Bernoulli suction, thermoregulatory coupling, path following, physical …

Males that exhibit alternative reproductive tactics (ARTs) often differ in the risk of sperm
competition and the energetic trade-offs they experience. The resulting patterns of selection …

Length of the sperm flagellum and of the female's primary sperm‐storage organ, the seminal
receptacle (SR), exhibit a pattern of rapid correlated evolution in Drosophila and other …

There is substantial comparative and growing experimental evidence that the competition for
fertilization among sperm from different males can drive variation in male reproductive …

When sperm compete to fertilize available ova, selection is expected to favour ejaculate
traits that contribute to a male's fertilization success. While there is much evidence to show …

Background The degree of postcopulatory sexual selection, comprising variable degrees of
sperm competition and cryptic female choice, is an important evolutionary force to influence …