Extrapolating from honeybees to bumblebees in pesticide risk assessment

Bumblebees are important pollinators of many crops and wild flowers and the re are both conservation and economic reasons for taking action to assess t he impact of pesticides on bumblebees. Pesticide risk assessments for honey bees are based on hazard ratios which rely on application rates and toxicit y data and are unlikely to be appropriate for bumblebees. Bumblebees are ac tive at different times and on different crop species and are, therefore, l ikely to have different exposure profiles. Unlike honeybees, deaths of bumb lebees due to pesticides are unlikely to be reported, since the bees are no t kept domestically and will die in small numbers. This paper highlights th e differences in the potential risk posed by pesticides to bumblebees from that of honeybees. This is based on their exposure through use of crops and flowering weeds and on available data on toxicity of pesticides. This info rmation is also intended as a source document for information on the foragi ng behavior and phenology of bumblebees for use in risk assessment for pest icides.