MOLECULAR MECHANISMS OF HONEY BEE MATING

Honey bees have a number of reproductive states, including virgin queens, laying virgin queens, instrumentally inseminated queens, and naturally mated queens (Winston 1987) . For these different reproductive states, we can monitor behavior (ie, egg-laying behavior or taking mating flights) pheromone production, ovary activation, and gene expression in both the brain and ovaries using microarray analysis. Queen pheromone production, in particular, is critical to colony organization and health, since it regulates many aspects of worker behavior (including worker reproduction and foraging) and inhibits rearing of new queens and swarming, which can reduce colony strength (Slessor et al. 2005) . Ultimately, our goal is to understand the physiological processes that cause post-mating changes in queens. At the molecular level, we hope to match gene expression patterns with specific physiological or behavioral changes. These studies will identify candidate genes and pathways that can serve as the basis for further functional analyses or as markers for breeding programs. This research has been conducted by two graduate students (Sarah Kocher and Elina Lastro Nino) and a post-doctoral associate (Freddie-Jeanne Richard, now an assistant professor at University of Poitiers, France), in collaboration with Professor David Tarpy (NCSU). We have found that brain gene expression and queen pheromone profiles are significantly modified by insemination quantity, in studies using instrumentally inseminated and natural mated queens (Kocher et al. 2008; Richard et al. 2007) . Furthermore, workers are attuned to these differences and are preferentially attracted to the pheromone produced by multiply mated queens. Our studies have demonstrated that both stretch receptors in the oviducts and seminal proteins appear to trigger post-mating changes (Richard et al. in prep, Kocher et al submitted) . Given that instrumental insemination is critical for honey bee breeding and selection (particularly to prevent accidental mating with Africanized bees), these results will allow us to develop modifications to the instrumental insemination process to further improve queen quality and colony health. These studies suggest that the production of queen pheromone is exquisitely sensitive to factors associated with reproduction and mating.