title: BEEHAVE: a systems model of honeybee colony dynamics and foraging to explore multifactorial causes of colony failure.
abstract: A notable increase in failure of managed European honeybeeApis melliferaL. colonies has been reported in various regions in recent years. Although the underlying causes remain unclear, it is likely that a combination of stressors act together, particularly varroa mites and other pathogens, forage availability and potentially pesticides. It is experimentally challenging to address causality at the colony scale when multiple factors interact.In silicoexperiments offer a fast and cost-effective way to begin to address these challenges and inform experiments. However, none of the published bee models combine colony dynamics with foraging patterns and varroa dynamics.We have developed a honeybee model, BEEHAVE, which integrates colony dynamics, population dynamics of the varroa mite, epidemiology of varroa-transmitted viruses and allows foragers in an agent-based foraging model to collect food from a representation of a spatially explicit landscape.We describe the model, which is freely available online (www.beehave-model.net). Extensive sensitivity analyses and tests illustrate the model's robustness and realism. Simulation experiments with various combinations of stressors demonstrate, in simplified landscape settings, the model's potential: predicting colony dynamics and potential losses with and without varroa mites under different foraging conditions and under pesticide application. We also show how mitigation measures can be tested.Synthesis and applications. BEEHAVE offers a valuable tool for researchers to design and focus field experiments, for regulators to explore the relative importance of stressors to devise management and policy advice and for beekeepers to understand and predict varroa dynamics and effects of management interventions. We expect that scientists and stakeholders will find a variety of applications for BEEHAVE, stimulating further model development and the possible inclusion of other stressors of potential importance to honeybee colony dynamics.
authors.affiliation: Environment & Sustainability Institute, University of Exeter, Penryn Campus Penryn, Cornwall, TR10 9FE, UK ; Rothamsted Research West Common, Harpenden, Hertfordshire, AL5 2JQ, UK.
authors.forename: Matthias A
authors.initials: MA
authors.lastname: Becher
authors.affiliation: UFZ, Helmholtz Centre for Environmental Research - UFZ Permoserstr. 15, 04318, Leipzig, Germany ; Institute for Biochemistry and Biology, University of Potsdam Maulbeerallee 2, 14469, Potsdam, Germany ; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Deutscher Platz 5e, 04103, Leipzig, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Grimm
authors.affiliation: Environmental Safety, Syngenta, Jealott's Hill International Research Centre Bracknell, Berkshire, RG42 6EY, UK.
authors.forename: Pernille
authors.initials: P
authors.lastname: Thorbek
authors.affiliation: UFZ, Helmholtz Centre for Environmental Research - UFZ Permoserstr. 15, 04318, Leipzig, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Horn
authors.affiliation: Environment & Sustainability Institute, University of Exeter, Penryn Campus Penryn, Cornwall, TR10 9FE, UK ; Rothamsted Research West Common, Harpenden, Hertfordshire, AL5 2JQ, UK.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kennedy
authors.affiliation: Environment & Sustainability Institute, University of Exeter, Penryn Campus Penryn, Cornwall, TR10 9FE, UK ; Rothamsted Research West Common, Harpenden, Hertfordshire, AL5 2JQ, UK.
authors.forename: Juliet L
authors.initials: JL
authors.lastname: Osborne
keywords: Apis mellifera; Varroa destructor; colony decline; cross-level interactions; feedbacks; foraging; modelling; multi-agent simulation; multiple stressors; predictive systems ecology