Bees, pollination and neonicotinoids
Neonicotinoids are a group of insecticides used for seed dressing or spraying, to protect crops from insect pests. Some neonicotinoids have been shown to negatively impact bees. However, studies to date have only artificially fed bees with low doses and no well designed and replicated study has examined if such impacts are observed for bees foraging under field conditions. In our projects on bees and neonicotinoids, we use well designed studies in real agricultural landscapes or in replicated cages to study the exposure and impacts of pesticides on both wild and managed bee species. We have two main projects; one focusing on the effects of clothianidin seed dressing in oilseed rape and the other one on thiacloprid spraying in red clover seed fields.
The oilseed rape study is divided into a field based part and a cage based part. The field based part is a collaborative project between the Swedish Board of Agriculture, Lund University, Swedish University of Agricultural Sciences, the Swedish Seed and Oilseed Growers Association and the Swedish Beekeeper Association (External project webpage). The study can reveal the level of neonicotinoid exposure in agricultural landscapes, as well as the field-realistic impacts of clothianidin seed dressing on bees foraging in such landscapes. In the cage based part of the project, we are able to keep a controlled environment and in detail study the bees.
In the clover study, we have been interested in estimating the exposure of bumble bees to thiacloprid in relation to the time since spraying and how this influence the density of pollinators in the crop field in this totally insect pollinated crop. We also estimated the effectiveness of the pesticide to control the seed eating weevil pest and assess the resulting impact on the seed yield.