Postcopulatory sexual selection is associated with reduced variation in sperm morphology.

ABSTRACT:

Background

The evolutionary role of postcopulatory sexual selection in shaping male reproductive traits, including sperm morphology, is well documented in several taxa. However, previous studies have focused almost exclusively on the influence of sperm competition on variation among species. In this study we tested the hypothesis that intraspecific variation in sperm morphology is driven by the level of postcopulatory sexual selection in passerine birds.

Methodology/findings

Using two proxy measures of sperm competition level, (i) relative testes size and (ii) extrapair paternity level, we found strong evidence that intermale variation in sperm morphology is negatively associated with the degree of postcopulatory sexual selection, independently of phylogeny.

Conclusions/s

SUBMITTER: Calhim S 

PROVIDER: S-EPMC1855076 | biostudies-literature | 2007 May

REPOSITORIES: biostudies-literature