Not all neonicotinoid insecticides have negative effects on bees, according to researchers at Lund University and the Swedish University of Agricultural Sciences. Their new study indicates that the use of certain neonicotinoids could benefit bumblebees and pollination.
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In a field study, the researchers Maj Rundlöf, Lund University, and Ola Lundin, the Swedish University of Agricultural Sciences, have found that the neonicotinoid thiacloprid does not have any detectable negative impact on bumblebees. When the insecticide was used on red clover fields, insect pests were successfully controlled while at the same time more bumblebees came to visit and pollinated the crop.
The study also showed that the bumblebee colonies close to the thiacloprid-treated red clover fields grew larger in comparison with bumblebee colonies in landscapes without red clover fields.
The research therefore indicates that certain neonicotinoids that are still permitted in the EU could actually benefit the bumblebees rather than harming them. The risk of direct impact on the bumblebees is low, while the thiacloprid protects the flowering fields where the bumblebees feed.
"Our study shows that neonicotinoids should not be treated as a homogenous group when evaluating the environmental risks of insecticides. There are pest management solutions that do not detectably harm bumblebees", says Maj Rundlöf.
Since 1 December 2013, there has been a ban within the EU on the use of three neonicotinoids on flowering crops. The ban concerns clothianidin, imidacloprid and thiamethoxam. The reason for the ban is that the substances have been identified as harmful to bees. In spring 2018, the EU tightened the ban, and now insecticides containing any of the three substances may only be used in permanent greenhouses.
If the recently studied neonicotinoid thiacloprid meets the same fate, it could lead to negative consequences for bumblebees, according to Maj Rundlöf.
"If this effective pest management solution was to disappear from the market without there being an adequate alternative, farmers would most likely grow less red clover seed and this would mean less food for the bumblebees", she say.
Thiacloprid is on the EU list of candidates for substitution, meaning it could be banned in the near future. This is because it has been found to have endocrine disruptive properties. However, Maj Rundlöf hopes future studies can build on the findings from this research.
"Our study nuances the view on neonicotinoids a little. The results open up to there being other alternatives within the neonicotinoid group that are not suspected to have endocrine disruptive properties. These could be alternatives for efficient pest regulation that are still acceptable for pollinators as well as humans", she concludes.