The effects of a mitotoxic fungicide on honey bee (Apis mellifera) queen oviposition

Honey bees are an integral part of agricultural systems all over the world. Though their economic and environmental contributions remain crucial, they are increasingly threatened by various environmental stressors. Agrochemical application, including fungicide use, aid in the protection of crops from pests and pathogens but adversely affect honey bee health and colony survival. To investigate the effects of a fungicide on honey bee reproduction and health, we tested the hypothesis that exposure to field relevant fungicide concentrations negatively affects honey bee queen egg laying rates and worker health. A non-treated control group was compared to three treatment groups consisting of various concentrations of Luna® Sensation fungicide (a.i.: fluopyram, trifloxystrobin). Our findings indicated that Luna® Sensation reduced egg laying rates at the highest concentration tested. Additionally, on average workers in the fungicide treated groups consumed more pollen than the control group which may impact hypopharyngeal gland size and quality. These findings suggest that fungicide consumption adversely affects honeybee queen reproductive competence which may reduce colony population levels.