A combination of the frequent fungicides boscalid and dimoxystrobin with the neonicotinoid acetamiprid in field-realistic concentrations does not affect sucrose responsiveness and learning behavior of honeybees

The effect of the fungicide Cantus Gold and the neonicotinoid insecticide Mospilan on the mortality, the responsiveness to sucrose and the learning performance of honeybees was tested. Mortality studies were performed for a low and a high concentration to determine two suitable sublethal doses for behavioral experiments. PER (proboscis extension response) tests and olfactory conditioning were conducted to investigate possible negative synergistic effects of the plant protection products. During the PER tests, a series of sucrose concentrations was presented to the bees and the response was noted (1/0). During conditioning, a rewarded (Nonanol) and a punished odor (Eugenol) were used, which were interchanged during reversal learning. Only bees that reacted to the highest concentration of sucrose water and showed no spontaneous reaction for both odors were conditioned. It was noted when the bee showed a conditioned response. There were no treatment effects on the responsiveness to sucrose and the learning performance.