Revisiting non-offspring nursing: allonursing evolves when the costs are low


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Authors
MacLeod, KJ 
Abstract

Allonursing, the nursing of another female's offspring, is commonly assumed to have evolved through the benefits of kin selection or reciprocity. The evolution of allonursing may also be influenced by variation in the possible costs to allonurses. The relative influence of costs and benefits on the incidence of allonursing in mammals remains unexplored. We show, using comparative analyses, that where females group with kin, the presence or the absence of allonursing is not associated with further variation in relatedness. Allonursing is most common where females produce litters; here the relative investment per offspring is low, and the costs of nursing additional young are likely to be reduced. Our results suggest that variation in the potential benefits is not associated with the distribution of allonursing, but that allonursing can quickly evolve when the costs to allonurses of nursing additional offspring are low.

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Journal Title
Biology Letters
Conference Name
Journal ISSN
1744-9561
1744-957X
Volume Title
10
Publisher
Royal Society Publishing
Sponsorship
NERC (NE/G006822/1)
D.L. received funding from ERC grant no. 294494-THCB2011.