The females of many species of primates settle for life within the home ranges of their mothers, whereas males disperse as immatures1. According to the theory of sex allocation, the costs incurred by mothers through local competition for resources with their philopatric daughters should favour the evolution of male-biased sex ratios at birth2,3. I report here two tests of this hypothesis based on data from 15 genera of primates. First, I show that the intensity of competition for resources within kin groups is strongly and positively correlated with sex ratios at birth. Second, I show that sex ratios at birth are higher in genera with female-biased philopatry than in genera in which philopatry is not female-biased. These analyses suggest that local resource competition among kin powerfully influences the evolution of sex ratios in primates.

Item Type:	Refereed Article
Keywords:	sex ratio evolution
Research Division:	Biological Sciences
Research Group:	Ecology
Research Field:	Behavioural Ecology
Objective Division:	Environment
Objective Group:	Flora, Fauna and Biodiversity
Objective Field:	Flora, Fauna and Biodiversity of environments not elsewhere classified
Author:	Johnson, CN (Professor Christopher Johnson)
ID Code:	84458
Year Published:	1988
Web of Science® Times Cited:	75
Deposited By:	Zoology
Deposited On:	2013-05-14
Last Modified:	2013-06-27
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