Sublethal effects of fipronil on the ability of honeybees ( Apis mellifera L.) to orientate in a complex maze

contribution to session IV Test methodology Normal 0 21 false false false DE X-NONE X-NONE MicrosoftInternetExplorer4 Background : The recent fipronil-based pesticide is accused by bee-keepers of causing depopulations in hives of honeybees ( Apis mellifera L.). Behavioural effects during the flight of foraging honeybees would have been evoked. To test whether the insecticide fipronil may disorientate foragers, its impact on orientation in a maze was examined. Bees had to fly through a sequence of boxes to reach the target, which was a feeder containing a reward of sugar solution. After being trained to associate a green mark with the reward, foragers received 1 μg kg -1 fipronil orally and their capacity to orientate through the maze following the colour mark was tested and compared to control. Results : The rate of foragers entering the maze, and so responding to the mark placed at the entrance, was reduced with fipronil-fed animals. Before and after treatment, 86-89% of bees equally flew through the whole path and arrived to the goal without mistakes. The rate of fipronil-treated bees finding path without mistakes decreased to 60%. Conversely, the rate of bees with unsuccessful searches for the goal notably increased with treatment (34% in treated bees versus 4% in control bees). Conclusion : Our results show that orientation capacities of foragers in a complex maze were affected by fipronil. Keywords: Apis mellifera L . , pesticide, maze, conditioning, visual learning, flight