Social dominance, task performance and nutrition: implications for reproduction in eusocial wasps.

Abstract

Dominance status is associated with individual differences in reproductive capacity in many animal societies, but the mechanisms that link social dominance to reproductive physiology are poorly understood. We propose a model for social dynamics that incorporates the nutritional costs and benefits of behavior: dominant individuals avoid energy-expensive behavior and build their nutritional reserves, thereby increasing their potential for reproduction. Greater reproductive capacity, once achieved, favors increased social dominance. To test the model, we measured relationships of females' nutrient storage and reproductive capacities with dominance status and task performance in the eusocial wasp Mischocyttarus mastigophorus. Ovary development was positively related with high levels of nutrient storage and with high rates of dominance behavior, but was not correlated with task performance. In contrast, high levels of nutrient storage were positively related with the performance of nutrient garnering and conserving tasks, but not with dominance behavior. These data support a model which places the nutritional costs of task performance as an intermediate causal link that connects dominance status with the accumulation of nutrient stores. Nutrient flow may be a general causal mechanism linking dominance status to reproductive capacity in animal societies.