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 […]