Biased escorts: offspring sex, not relatedness explains alloparental care patterns in a cooperative breeder

Vitikainen, Emma I. K.; Marshall, Harry H.; Thompson, Faye J.; Sanderson, Jenni L.; Bell, Matthew B. V.; Gilchrist, Jason S.; Hodge, Sarah J.; Nichols, Hazel J.; Cant, Michael A.

Abstract

Kin selection theory predicts that animals should direct costly care where inclusive fitness gains are highest. Individuals may achieve this by directing care at closer relatives, yet evidence for such discrimination in vertebrates is equivocal. We investigated patterns of cooperative care in banded mongooses, where communal litters are raised by adult ‘escorts’ who form exclusive caring relationships with individual pups. We found no evidence that escorts and pups assort by parentage or relatedness. However, the time males spent escorting increased with increasing relatedness to the other group members, and to the pup they had paired with. Thus, we found no effect of relatedness in partner choice, but (in males) increasing helping effort with relatedness once partner choices had been made. Unexpectedly, the results showed clear assortment by sex, with female carers being more likely to tend to female pups, and male carers to male pups. This sex-specific assortment in helping behaviour has potential lifelong impacts on individual development and may impact the future size and composition of natal groups and dispersing cohorts. Where relatedness between helpers and recipients is already high, individuals may be better off choosing partners using other predictors of the costs and benefits of cooperation, without the need for possibly costly within-group kin discrimination.

Citation

Vitikainen, E. I. K., Marshall, H. H., Thompson, F. J., Sanderson, J. L., Bell, M. B. V., Gilchrist, J. S., …Cant, M. A. (2017). Biased escorts: offspring sex, not relatedness explains alloparental care patterns in a cooperative breeder. Proceedings of the Royal Society B: Biological Sciences, 284(1854), 20162384. https://doi.org/10.1098/rspb.2016.2384

• Journal Article Type: Article
• Acceptance Date: Apr 11, 2017
• Online Publication Date: May 3, 2017
• Publication Date: May 17, 2017
• Deposit Date: Jun 12, 2017
• Publicly Available Date: Jun 14, 2017
• Journal: Proceedings of the Royal Society B: Biological Sciences
• Print ISSN: 0962-8452
• Electronic ISSN: 1471-2954
• Publisher: Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 284
• Issue: 1854
• Pages: 20162384
• DOI: https://doi.org/10.1098/rspb.2016.2384
• Keywords: cooperative breeding, nepotism, helping, altruism, sex-biased care, alloparental care
• Public URL: http://researchrepository.napier.ac.uk/Output/930623