HB Dynamics: A new stage structured model of honey bee (Apis mellifera) colony dynamics

As an aid to testing hypotheses for the causes of recent colony failure and providing suggestions for management actions to promote recovery of honey bee populations, we developed a female only, age-structured model of honey bee population dynamics. This model was formulated with difference equations consisting of six discrete stages based on honey bee temporal polyethism: egg, larva, pupa, nurse, and house bee and forager stages. The model contains multiple feedback mechanisms in population dynamics and resource dynamics including brood maintenance, space limitation, and collective foraging behaviors for nectar and pollen.  Numerical simulation of a healthy colony shows seasonal patterns of three adult populations, the brood population, pollen and honey stores, and queen egg laying output, which are in good agreement with several empirical colony studies from the literature as well as from our own experiments. This high degree of biological validation for the model has encouraged us to begin using model simulations of various scenarios of a weakened colony and of testing whether or not subtle changes at the individual or social group level by potential stressors could result in substantial outcomes at the colony level. Our model yields first generation results of wide-reaching heuristic value relevant to unresolved questions about colony dynamics forecasting under the combination of multiple stressors. Our model is a new tool for suggesting hypothesis-driven research into the underlying mechanisms which regulate colony dynamics and health, for testing alternatives, and for providing suggestions for new approaches to colony management.