Field assessment of impacts of different neonicotinoids on honey bee queens and drones
Neonicotinoids have been among the most frequently used insecticides in the cultivation of several crops and orchards. Till 2012, imidacloprid represented 41.5% of the whole neonicotinoid market and thiamethoxam was the second biggest neonicotinoid, followed by clothianidin. However, almost two years ago, a decision was made by the EC parliament to ban the use of these three compounds for two years and this will soon be re-addressed. Our aim was to determine the effect of particular neonics on: the life span of queens, effects on egg laying or brood development, sperm viability and overwintering ability when particular neonicotinoids were fed to the colonies in low and very high sub-lethal field realistic doses (e.g. 5ppb and 200 ppb respectively for imidacloprid; 20 ppb, 200 ppb and 400 ppb respectively for clothianidin); a control group was also evaluated. Additionally we looked at the colony population dynamics. The experiment was set up in different countries using the local honeybee populations and it was run during spring –summer 2013 and 2014. The first comprehensive results are presented: they show a detrimental effect of the high doses of the neonicotinoids used, while the effects of the low doses were variable and dependent on the application dose, the year and the feeding quantity of the contaminated food. Further work is needed to be done on the same direction. This research work has been undertaken by members of COLOSS honey bee research association.