Ant workers selfishly bias sex ratios by manipulating female development.

RL Hammond, MW Bruford, AFG Bourke

Research output: Contribution to journalArticlepeer-review

58 Citations (Scopus)

Abstract

Kin selection theory predicts that social insects should perform selfish manipulations as a function of colony genetic structure. We describe a novel mechanism by which this occurs. First, we use microsatellite analyses to show that, in a population of the ant Leptothorax acervorum, workers' relatedness asymmetry (ratio of relatedness to females and relatedness to males) is significantly higher in monogynous (single–queen) colonies than in polygynous (multiple–queen) colonies. Workers rear mainly queens in monogynous colonies and males in polygynous colonies. Therefore, split sex ratios in this population are correlated with workers' relatedness asymmetry. Together with significant female bias in the population numerical and investment sex ratios, this finding strongly supports kin–selection theory. Second, by determining the primary sex ratio using microsatellite markers to sex eggs, we show that the ratio of male to female eggs is the same in both monogynous and polygynous colonies and equals the overall ratio of haploids (males) to diploids (queens and workers) among adults. In contrast to workers of species with selective destruction of male brood, L. acervorum workers therefore rear eggs randomly with respect to sex and must achieve their favoured sex ratios by s
Original languageEnglish
Pages (from-to)173-178
Number of pages6
JournalProceedings of the Royal Society B: Biological Sciences
Volume269
Issue number1487
DOIs
Publication statusPublished - 22 Jan 2002

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