A modeling approach to swarming in honey bees (Apis mellifera)

Abstract. Identifying the mechanisms of colony reproduc-tion is essential to understanding the sociobiology of honey bees. Although several proximate causes leading to the initi-ation of queen rearing – an essential prerequisite to swarm-ing – have been proposed, none have received unequivocal empirical support. Here we model the main proximate hy-potheses (colony size, brood comb congestion, and worker age distribution) and show that all proposed swarming trig-gers occur as a function of the ultimate cause of a colony reaching replacement stability, the point at which the queen has been laying eggs at her maximal rate. We thus present a reproductive optimization model of colony swarming based on evolutionary principles. All models produce results re-markably similar both to each other and to empirically-deter-mined swarming patterns. An examination of the fi t between the individual models and swarm-preventing techniques used by beekeepers indicates that the reproductive optimiza-tion model has a relatively broad explanatory range. These results suggest that an examination into the behavioral cor-relates of a queen’s maximum egg laying rate may provide a unifi ed proximate mechanistic trigger leading predictably to colony fi ssion. Generating a predictive model for this very well studied animal is the fi rst step in producing a model of colony fi ssion applicable to other swarm-founding eusocial animals