Meeting Abstract
Honeybees (Apis mellifera) have experienced global declines linked to Colony Collapse Disorder (CCD). While CCD may be due to many factors, Varroa mites strongly influence hive health, directly as an ectoparasite and indirectly as a disease vector. Beekeepers control mites with acaracides, pesticides used to kill mites. We hypothesized that acaracides may cause sublethal stress in honeybees. The intracellular chaperone heat shock protein 70 (HSP70) has been shown to be an excellent biomarker for sublethal stress in bees. This research aimed to determine the levels of HSP70 in honeybees pre- and post-treatment with synthetic pesticides (coumaphos, an organophosphate and flumethrin, a pyrethroid) or natural (organic) pesticides formic acid, thymol mix, and oxalic acid). Pesticides were applied by standard beekeeping practices at manufacturers’ recommended dosages for treatments of Varroa infestations. Bee samples were collected pre- and post-treatment. HSP70 levels were measured by ELISA in homogenized head capsules. Among the synthetic pesticides, coumaphos did not affect HSP70 levels while flumethrin decreased HSP70 levels, possibly associated with mite abatement. Among the natural pesticides, the thymol mix decreased HSP70 levels. The method of oxalic acid application affected sublethal stress levels; liquid oxalic acid treatment increased HSP70 levels, while steamed oxalic acid had no effect. Formic acid did not affect HSP70 levels. These findings suggest that the thymol mixture and flumethrin caused the least sublethal stress to bees and corroborates that bees are more sensitive to oxalic acid than formic acid, as natural acaracides.
