Distribution of females influences the evolution of testes size in Australian rodents

The evolution of testes size of males in 33 Australian rodents is affected by the distribution of females.

According to evolutionary biology researchers from the University of Western Australia, female availability influences the strength of sperm competition in rodents.

Insights into reproduction and male fertility will help researchers to understand and support the preservation of Australia's rodents, which are threatened by introduced predators, habitat clearance and degradation.

She says that they used analyses on 33 species of rodents to understand the link between the spatial and temporal distribution of females and sperm competition.

We found that males of these social species had smaller testes compared to solitary species, suggesting that dominance among social males leads to reduced levels of sperm competition.

The study found that the level of sperm competition in Australian rodents is related to the temporal synchrony of female receptivity.

The results suggest that males may be effective in monopolizing reproduction within social groups, which leads to reduced levels of sperm competition relative to non-social species where free-ranging females cannot be controlled.

Overall, our results show that patterns of female distribution can influence the strength of post-mating sexual selection among species.

Patterns of female distribution will affect the strength of sperm competition, as well as the extent to which males are able to prevent female remating.

The study helps us understand how the spatial and temporal distribution of mating opportunities have shaped the evolution of sperm competition.

More information: Renée C. Firman et al, The spatial and temporal distribution of females influence the evolution of testes size in Australian rodents, Biology Letters (2022). DOI: 10.1098/rsbl.2022.0058 Journal information: Biology Letters Citation: Distribution of females influences the evolution of testes size in Australian rodents (2022, May 4) retrieved 4 May 2022 from https://phys.org/news/2022-05-females-evolution-size-australian-rodents.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.