Group size, productivity, and information flow in social wasps

Social wasp species segregate into two behavioral groups: independent founders, in which queens found new colonies independent of workers, and swarm founders, in which new colonies are founded by swarms comprising several queens accompanied by many workers. Recent work on Polybia occidentalis, a swarm founder, indicates that productivity (measured as nest size and grams of brood reared) per adult per day increases with founding swarm size. I consider four mechanisms than can account for this pattern, and adduce *evidence supporting two of them. First, large colonies appear to allocate a larger proportion of their worker population to foraging for resources. Second, foragers in large colonies transfer their materials to nest workers more efficiently than in small colonies. I suggest that differences in the stochastic properties of small versus large groups lead to shorter queuing delays and a greater ability of large colonies to keep the size of interacting worker groups in balance in the face of perturbations and changing conditions. Finally, I argue that the mode of social organization seen in the swarm founders works most efficiently for large groups, while the simpler organization of independent founders works most efficiently for very small groups.