Meeting Abstract

P1.107  Sunday, Jan. 4  Reproductive roles in Polistes dominulus: The cost of maintaining ovarian development WEINER, S.A*; BAUTISTA, G.M.; SANDERS, D.B.; RYAN, J.; WOODS, W.A.; STARKS, P.T.; Tufts University; Tufts University; Morehouse College; Northern Essex Community College; Tufts University; Tufts University susan.weiner@tufts.edu

Polistes paper wasps are an important model system for studying the evolution of eusociality, because the castes are totipotent, and as such, workers can reproduce. However, workers and subordinate foundresses reproduce little if at all on most nests and generally have ovaries that are much less developed than those of dominant or solitary foundresses. In order to add to our understanding of why wasps would not maintain fully developed ovaries, we measured the energetic cost of maintaining reproductive development in workers and in dominant, subordinate and solitary foundresses. The resting metabolic rate (RMR) of each wasp was found by measuring CO₂ production and ovarian development was determined by measuring average egg. Egg length was correlated strongly with RMR, indicating that maintaining ovaries is energetically costly. In addition, egg length relative to headcap width was also correlated with mass-specific RMR, indicating that it is more energetically costly for smaller animals (such as workers and subordinates) to maintain highly developed ovaries. Furthermore, the slope of RMR on egg length was higher for workers than for foundresses, suggesting that it was more difficult for workers to maintain larger ovaries. These costs may partially explain why workers and subordinates do not maintain fully developed ovaries.