Intraspecific variation in sperm morphometric is widespread across animal taxa and it might be related to different aspects of sexual selection. Within social insects, it has only been documented for some bee and ant ...

In polyandrous species, sperm morphometry and sperm velocity are under strong sexual selection. Although several hypotheses have been proposed to explain the role of sperm competition in sperm trait variation, this aspect ...

The epididymal sperm transit time seems to have an important role in the process of sperm maturation, and it seems that alterations to the transit can harm the process. The aim of the present work was to evaluate the ...

Inseminations with frozen-thawed epididymal sperm have resulted in low-pregnancy rates of mares. If fertility of epididymal sperm could be improved, it would help to preserve genetic material from stallions that have ...

There is a natural range of variation in sperm morphology inside males. This variation may be adaptive or a result of poor quality control of sperm production. Sperm aggregates can also show different morphologies inside ...

Sperm competition (SC) occurs when the sperm of two or more males compete for the same set of ova. Theoretical models and experimental observations indicate that the presence of rival males causes focal males to adjust ...

The development of a reliable technique to freeze epididymal semen would provide a unique opportunity to preserve valuable genetic material from unexpectedly lost stallions. The aim of this study was to compare the apoptotic ...

Tritrichomonas fetus causes infertility and abortion in cattle; however, there is scarce information regarding the susceptibility of bovine sperm to this parasite. The objective of this study was to analyze in vitro the ...

The role of sperm competition in increasing sperm length is a controversial issue, because findings from different taxa seem contradictory. We present a comparative study of 25 species of snakes with different levels of ...