Wasp Reproduction and Kin Selection: Reproductive Competition and Dominance Hierarchies among Polistes annularis Foundresses

Abstract

P. annularis foundresses can be ranked in a dominance hierarchy according to aggressive behaviors. Females at the top of the hierarchy lay more eggs, tailwag more, and smear more while females at the bottom of the hierarchy forage for caterpillars more. The top-ranked females or queens differ more from all their subordinates than the subordinates differ among themselves. Subordinates are most different from queens on nests with larvae and pupae as the most advanced brood stages. On nests with only eggs, queens forage and differ little from subordinates. When workers emerge from the nest, subordinate foundresses stop working. On the average, queens lay 80% of all eggs, and subordinates overthrow queens on .apprx. 35% of all nests; thus, highly ranked subordinates have opportunities to lay eggs. When reproductive success is calculated using the concept of offspring equivalents, it is found that subordinates produce more offspring equivalents as subordinates than they would have by nesting alone. The larger the group of foundresses, who are assumed to be sisters, the greater the number of offspring equivalents attributed to the queen and the second-ranked female. These findings support the theory of kin selection.