Abstract: One of the main contributors to poor productivity and elevated mortality of honey bee colonies globally is insecticide exposure. Whole organism and colony-level studies have demonstrated the effects of insecticides on many levels of honey bee biology, as well as reveal interactions with pathogens. However, there is a need for in vitro studies using cell lines to provide greater resolution of the effects of insecticides on honey bee cellular and molecular processes. Here, we used a continuous cell line established from honey bee embryonic tissues, AmE-711, in assays that enabled assessment of cell viability in response to insecticide exposure. We exposed AmE-711 cells to four formulations each containing a different insecticide. Treatment of cells with the insecticides resulted in a concentration-dependent reduction in viability after a 24-hour exposure, while long-term exposure (120 hours) to sublethal concentrations had limited effects on viability. The 24-hour exposure data allowed us to predict the half maximal lethal concentration (LC50) for each insecticide using a four-parameter logistical model. We then exposed cells for 12 hours to the predicted LC50 and observed changes in morphology that would indicate stress and death. RT-qPCR analysis corroborated changes in morphology, as expression of a cellular stress response gene, 410087a, increased after an 18-hour exposure to the predicted LC50. Demonstration of the effects of insecticides through use of AmE-711 provides a foundation for additional work addressing issues specific to honey bee toxicology and complements whole organism and colony-level approaches. Moreover, advancement of AmE-711 for use in high-throughput screening and in-depth analysis of cell regulatory networks will promote discovery of novel control agents with decreased negative impacts for honey bees.
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