Quieting the buzz: Agrochemicals are having a worse effect on bee numbers than expected – Louise Elliott
A group of scientists, jointly led by Dr. Emily Bailes of the University of Sheffield, have conducted a meta-analysis of previous studies, finding that the impacts of agricultural chemicals on bee mortality have been largely underestimated.
Often, the impacts of agrochemicals, such as pesticides and herbicides, on bee morality are tested on an individual basis. However, the recent analysis of 90 such studies shows that interactions between these chemicals can have a much deadlier impact on bees than first expected.
This raises important questions as to whether current agrochemical regulatory processes are doing enough to support bee populations. If the current risk assessment schemes on which these regulations are based fail to account for the cumulative effect of multiple chemicals on bee mortality, they may be insufficient to protect bee populations for the future.
On the findings of this study, Dr. Emily Bailes said: “We found that when bees were exposed to multiple agrochemicals, like pesticides or herbicides, they generally acted in a way which caused more damage than would be expected from assessing each pesticide individually.
“This is important because when pesticides are tested for their environmental impact they are usually tested as the only stress that bees are experiencing, rather than as one of multiple stressors that bees experience in nature.”
Bees, and other pollinator species, have been declining in number for decades leading to increased risk to global food security. Many individual stressors, such as parasites and nutritional factors as well as agrochemicals, all contribute to this decline. However, until now studies examining the combined effects of these individual stressors have produced inconclusive results.
