Tracking pollinator movements and resource use in response to environmental stressors at a landscape scale

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Bees play a critical role in food production and facilitating reproduction of wild flowering plants. In Canada, bumblebees emerge in spring and are often seen buzzing around farms visiting the blooms of fruit and vegetable crops. Like other bees, bumblebees also seem to be struggling in human influenced landscapes. Loss and fragmentation of important habitat for food and nesting sites, greater pesticide exposure, higher risks from parasites/pathogens and climate change are all challenges for wild bees, and these factors may be more harmful when acting together. Although bumblebees are perhaps the most apparent and best studied of Canada's wild bees, there are still big gaps in our understanding of their basic ecology that we need to fill in order to conserve these pollinators more effectively. Bumblebee queens in particular are poorly studied so we have little idea of how far they travel after emerging from hibernation underground to find food and possible nest sites where they can start their own colony. Similarly estimates of the dispersal distances of newly emerged virgin queens in late summer vary hugely at a time they must find a mate and then a safe place to bury themselves to survive the cold winter in hibernation. We will set out to fill these important knowledge gaps using a unique radio tracking array with 49 receiver towers to automatically follow the movements of tagged bumblebees in real time. We will also examine spatial foraging patterns of bumblebee workers on bee attractive field crops (e.g. blueberry) and see how these are governed by the distribution and availability of habitat in the farmed landscape. We will also investigate the potential sublethal effects of exposure to field realistic levels of pesticides on the behaviour of radio-tagged queens and workers. Particularly for queens even a subtle change from normal behaviour could have a profound effect on her success at finding a nest site or raising a colony. Robust estimates on the rate of bumblebees surviving winter will be collected by allowing many fall queens to bury themselves in flight enclosures into which survivors will emerge again in spring. Tracking the genetic relatedness among workers will also inform our understanding of annual fluctuations in local population structure. A key aim of this program is to bring together all these new data on key life history transitions to build an ecologically realistic demographic model for the bumblebee colony lifecycle. Such a ground-truthed model will allow us to better understand the ways in which environmental stressors perturb colony success by affecting individual bee physiology and behaviour, particularly if this is the queen. Building a complete understanding of the key habitat requirements for different bumblebee species to live and thrive gives us wider insights into bee biology and also increases our ability to provide targeted advice and action to conserve bumblebees as essential pollinators.