Coumaphos affects food transfer between workers of honeybee Apis mellifera

Abstract

We investigated whether coumaphos, an organophosphate used to control the parasitic mite Varroa destructor, affects trophallaxis in honeybees. Donors were treated with coumaphos 1 h before experiments. In this, uncontaminated food was transferred from donors to recipients. The amount of food transferred was measured (a) directly by weighing food or (b) indirectly by the number of recipients that died due to insufficient trophallaxis. A large reduction in the amount of transferred food was observed when the donors received 5 μg of coumaphos 1 h prior to the experiment. High mortality was observed among the recipients that were fed by donors treated with 2 or 5 μg of coumaphos indicating insufficient food transfer. Demonstrated side effects of coumaphos on trophallaxis could reduce distribution of this systemic agent in the colony and decreases its efficacy. The described assays are feasible and could be a useful tool to test the effects of pesticides on trophallaxis.