Sub-Lethal Effects of Imidacloprid Exposure on Honey Bee Queen Egg-Laying and Activity

Wu, J., V. Krischik and M. Spivak, Department of Entomology, University of Minnesota; St. Paul, MN 55108
Abstract for the 2012 American Bee Research Conference, February 7-8 2012 Greenbelt.

Pesticides such as neonicotinoid insecticides have been implicated as a contributing factor to honey bee losses. The objective of this study is to examine sub-lethal effects of imidacloprid on honey bee queen egg-laying and activity. Observation hives, containing about 1500 bees and a laying queen on newly drawn comb, were given 80 ml of sugar syrup with various imidacloprid treatments (0, 20, 50, 100 ppb) every other day. A total of 16 observation hives, or 4 colonies per treatment, were set-up in July and August of 2011. Queen egg-laying rate and activity were recorded in 15-minute intervals and quantified over 3 weeks. After 3 weeks, colonies were quantified for total adult and brood population, nectar and pollen stores, presence of disease, and weight of newly emerged bees. Preliminary results show that queen laying rates were affected at each imidacloprid treatment dose (20, 50, and 100 ppb). This study will be repeated in the summer of 2012. The findings will improve our understanding of known imidacloprid studies on honey bee colonies and workers. In addition, this study will highlight the need to focus future risk assessment studies on sub-lethal effects of neonicotinyl insecticides on honey bee queen health and behavior.