Statement on the findings in recent studies investigating sub-lethal effects in bees of some neonicotinoids in consideration of the uses currently authorised in Europe

Neonicotinoids, sub-lethal effects, honeybees, bumblebees, exposure, nectar
First published in the EFSA Journal
1 Junio 2012
31 Mayo 2012
Last Updated
21 Marzo 2017. This version replaces the previous one/s.
Statement of EFSA


The European Food Safety Authority was requested to perform a comparison between the doses of several neonicotinoids tested in the studies from Henry et al. (honeybees, thiamethoxam) and Whitehorn et al., (bumblebees, imidacloprid) published in Science (2012) with exposure of bees, following the actual use of these neonicotinoids. A third study investigating sub-lethal effects on honeybees for clothianidin and imidacloprid was also considered (Schneider et al., 2012). Data of uses authorised in EU and data on residues in pollen and nectar were collected to compare the actual exposure of bees with the investigated doses. The residue data were limited and available only for some crops; therefore, the extrapolation to other crops was not considered appropriate. In the studies on honeybees, the highest residue levels of thiamethoxam, clothianidin and imidacloprid in nectar were compared with the actual concentrations tested. The results indicated that the tested concentrations were higher than the concentrations found in nectar. The residue intake was estimated using different exposure scenarios. The results indicated that the doses tested in these publications were lower for clothianidin and for thiamethoxam than the estimated exposure. For imidacloprid the doses tested were higher in all the scenarios. In the studies on honeybees, the total amount of active substance was consumed by honeybees within a relatively short period instead of being not administrated over a longer period i.e a day. In the study on bumblebees the tested concentrations were in the range of the highest residues of imidacloprid in pollen and nectar. However, the relevance of the exposure period in the study is unknown. The comparison between the doses tested in the studies with the actual doses with the exposure of bees was considered feasible only for the seed treatment uses to maize, sunflower, oilseed rape and alfalfa. Further data would be necessary before drawing a definite conclusion on the behavioural effects regarding sub-lethal exposure of foragers exposed to actual doses of neonicotinoids

European Food Safety Authority
pesticides.peerreview [at]
EFSA Journal 2012;10(6):2752
Question Number
On request from
European Commission