In mammals, female reproductive rate (fecundity) is increased when males provide food or contribute to rearing offspring, finds a study published in Nature Communications this week. Care by males is associated, in females, with shorter lactation periods, larger litters of offspring, and more frequent breeding events.
Females invest significant resources in rearing their offspring in all mammal species. However, males contribute to caring for offspring either directly or indirectly by provisioning food for the mother in only about 10% of mammal species. For males, providing care can mean giving up on additional mating opportunities, and is more likely to evolve when males gain greater certainty of paternity or when future mating opportunities are scarce.
In order to investigate potential additional benefits of male care, Hannah West and Isabella Capellini compile and analyze a dataset of the life history characteristics and male helping behaviours (including providing food for either the mother or the offspring, and huddling, grooming, and carrying the offspring) of 529 mammal species. Taking into account the species’ evolutionary history, they find that, male provision of food for females is associated with larger litters. Additionally, the authors show that both provisioning for females and helping to carry offspring are associated with shorter lactation periods, which in turn enable more frequent breeding events.
These findings suggest that male care may increase long term reproductive opportunities and that this may compensate for fewer mating opportunities in the short term.