Effects of synthetic acaricides on honey bee grooming behavior against the parasitic Varroa destructor mite

Abstract

Varroa destructor is currently one of the main threats for western apiculture. Today, synthetic acaricides (specifically coumaphos, amitraz, and tau-fluvalinate) are the most common methods to control Varroa infestations. These compounds, however, are frequently related to a wide range of side effects in the host, as well as a long half-life inside the hive matrices (wax and honey). The western honey bee, Apis mellifera, exhibits natural defense mechanisms against the mite such as grooming behavior, which is a sequence of bodily movements where the host scrapes its legs across its body surface to remove the mite. We tested the effects of synthetic acaricides on the performance of grooming behavior by adult honey bee workers. We found that acaricide exposure prior to grooming delayed grooming and reduced the overall duration of grooming behavior. Our data add to a list of other sublethal behavioral consequences of acaricides that may subvert a comprehensive approach to Varroa control in managed colonies.