Patterns of split sex ratio in ants have multiple evolutionary causes based on different within-colony conflicts.
Split sex ratio-a pattern where colonies within a population specialize in either male or queen production-is a widespread phenomenon in ants and other social Hymenoptera. It has often been attributed to variation in colony kin structure, which affects the degree of queen-worker conflict over optimal sex allocation. However, recent findings suggest that split sex ratio is a more diverse phenomenon, which can evolve for multiple reasons. Here, we provide an overview of the main conditions favouring split sex ratio. We show that each split sex-ratio type arises due to a different combination of factors determining colony kin structure, queen or worker control over sex ratio and the type of conflict between colony members.
Kümmerli
Rolf
R
Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK. rolf.kuemmerli@ed.ac.uk
Keller
Laurent
L
D000818:Animals; D001000:Ants / Q000235:genetics / Q000502:physiology*; D005075:Biological Evolution; D005260:Female; D008297:Male; D011003:Ploidies; D011157:Population Dynamics; D012098:Reproduction / Q000235:genetics / Q000502:physiology; D012744:Sex Ratio; D012726:Sexual Behavior, Animal