Speaker: Hermann J Eberl, University of Guelph

Title:  "Chaos in the Hive and Beyond: A Multiscale Mathematical Model of Nosemosis in an Apiary and Its Study in COmputer SImulation Experiments"

Abstract: In the last 14 years or so, many mathematical models of honey bee population and disease dynamics have appeared in the literature. In most instances, these studies consider a single colony, often a generic rather than a specific disease, and are formulated as a system of autonomuous ordinary differential equations that permit the application of classical infectious disease modeling tools. We will present an apiary level model where the disease is spread between hives by drifting foragers. The model considers the seasonality of honey bee biology, and two routes of transmission that both have been proposed for Nosemosis, a contagious disease that weakens colonies. The resulting eco-epidemiological metapopulation model consists of 80 non-autonomuous ODEs (5 per colony; 16 colonies in an apiary) that we investigate in painstaking computer simulations. Originally to our surprise, we find highly complex and unexpected behavior such as period doubling and chaos in some parameter regimes. This seems to be caused by an intricate interplay of seasonality and population strength requirement for brood/hive maintenance. Our simulations also suggest that higher forager drifting rates may help survive individual colonies. This is joint work with Nasim Muhammad (Mohawk College, Hamilton ON).