Flowers for health: the importance of flower diversity and composition for maintaining the health and disease resistance of bumblebee pollinators

Bumblebees are amongst the most ecologically and economically important groups of pollinators, but many species are suffering serious declines. Out of 25 bumblebee species in the UK, for example, 2 have gone extinct and 8 decreased substantially in abundance since 1940, while 13 species have gone extinct in at least one European country and four across the entire region. Reasons for the declines include habitat loss and nutritional stress, pesticide exposure, and both existing and emerging diseases. The importance of bumblebees for crop pollination and sustainable food production means that their declines are of economic as well as conservation significance. Britain's already vulnerable bumblebee populations currently face additional risks from emerging diseases, including pathogens which spillover from honeybees and from commercially produced bumblebee colonies which are imported for crop pollination. However, the roles of flower diversity and composition in maintaining the health and resistance to disease of bumblebees is unclear, and a strong understanding of this is crucial to inform the provision of flower resources in conservation and agricultural schemes. This project will investigate the effects of the diversity and composition of flower resources on the health and disease resistance of bumblebees, including rare bumblebee species. It will combine controlled laboratory experiments to precisely determine the impact of food resources on bees, field experiments in managed habitats that provide different levels of food resource, and the examination of parasite levels in wild bumblebees in different environments, to disentangle the role and ecological significance of flower diversity and composition for bumblebee health and disease resistance. The results will provide a substantial advance in our understanding of the importance of food resources and nutritional stress in the susceptibility of bumblebees to disease. The project will deliver the evidence for appropriate management of habits for bumblebee conservation, thereby supporting bee biodiversity and their ecosystem services for sustainable food production, and will provide a first-class training experience for the student that will encompass academic research, public engagement and practical conservation skills.