Sperm competition and sperm midpiece size: no consistent pattern in passerine birds.

ABSTRACT: Sperm competition is thought to be a major force driving the evolution of sperm shape and function. However, previous studies investigating the relationship between the risk of sperm competition and sperm morphometry revealed inconclusive results and marked differences between taxonomic groups. In a comparative study of two families of passerines (Fringillidae and Sylviidae) and also across species belonging to different passerine families, we investigated the relative importance of the phylogenetic background on the relationship between sperm morphometry and the risk of sperm competition. The risk of sperm competition was inferred from relative testis mass as an indicator of investment in sperm production. We found: (i) a significant positive association between both midpiece length and f

SUBMITTER: Immler S 

PROVIDER: S-EPMC1766377 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature