Pheromones, Pathogens and Pesticides: How do these interact to affect the health and productivity of social and solitary bees?

Honeybees, bumblebees and other bee species are facing a multitude of threats from disease, pesticide exposure and loss of habitat. These threats have resulted in alarming declines in bee numbers, which is a concern for food security, biodiversity and conservation.

Probably the best known and arguably the most important bee species for pollination is the honeybee, Apis mellifera. The honeybee and the bumblebee are the most extensively managed pollinator species globally and much of the research on bees has focussed on these two species. These bees are both 'eusocial' - they live in colonies with hundreds to thousands of individuals. In each colony, there is only one reproductively active female who is responsible for the majority of reproduction and workers carry out most other colony tasks. Because these eusocial bees live in large colonies they are susceptible to diseases, and honeybees, in particular, are commonly afflicted with several viruses and parasites.

Pheromones are crucially important in all insects but especially in eusocial bees and act as a as primary means of communication regulating a range of behaviours in the hive including, looking after the queen, comb building and division of labour. There is substantial overlap in the behaviours modulated by pheromones in the hive and the sub-lethal effects of pesticides e.g. foraging activity, sucrose sensitivity and reproduction leading to the novel hypothesis that some of the sub-lethal effects of pesticides are modulated by pheromones produced within the colony.

Pheromones are equally important for solitary species too and play an important role in mate attraction. The UK is also home to 250 species of solitary bees - these bees spend the majority of their lives on their own, only getting together to mate, and individual females forage, lay eggs and collect provisions for their offspring. Many of these solitary bees use the same flowers and honeybees and bumblebees, and so are exposed to the same pesticides and may even be exposed to the pathogens transmitted from eusocial bees via indirect transmission. Yet, we don't know if or how these environmental stressors affect the health, mating and reproduction of solitary bees.

This project will combine behavioural ecology with molecular approaches to understand how pheromones, pesticides and common diseases affect social (bumblebees and honeybees) and solitary bees (e.g. the red mason bee) using a combination of laboratory and field-studies.