Male house mice do not adjust sperm allocation in response to odours from related or unrelated rivals

Sperm competition theory predicts that males should adjust the number of sperm they ejaculate adaptively, according to sociosexual cues of sperm competition at the time of mating. Specifically, it is predicted that (1) males will respond to an increased risk of sperm competition from rivals by increasing sperm allocation, and (2) the increase in allocation […]

Prudent sperm allocation in Norway rats, Rattus norvegicus: a mammalian model of adaptive ejaculate adjustment

In species where there is postcopulatory competition between males in the form of sperm competition, theory predicts that males should show prudent sperm allocation. Specifically, males should adjust the number of sperm that they inseminate in response to variations in the risk and intensity of sperm competition. Some experimental evidence for nonmammalian species indicates that […]