Regulation of defensive behavior by for gene expression and juvenile hormone in the little fire ant, Wasmannia auropunctata

Defensive behavior of social insects has been associated with concentration of Juvenile Hormone (JH) and the genetic expression of the foraging gene (for). In the honey bee (Apis mellifera), individuals who perform defensive tasks have relatively higher levels of JH. In the ant Pheidole pallidula and A. mellifera, studies suggest that defending individuals have relatively high expression of for in comparison to non-defending individuals. The little fire ant (Wasmannia auropunctata) exhibits age-related division of labor where, in this species, young individuals take care of brood, the queens and defend the nest, and older individuals search for resources and are capable of performing nursing tasks when young workers are absent. Results of our previous studies of W. auropunctata suggest a relationship between JH and defensive behavior where defense is related to high levels of JH and not necessarily age. We will evaluate the role JH and for in defensive behavior, and how different levels and expressions regulate defensive response. For this, we will be conducting behavioral plasticity and defense assays, hormone treatments using the JH analog Methoprene and gene expression analysis. We will specifically measure the expression of for and JH through JHbp in ants performing and not-performing defense of the nest. We expect that individuals of W. auropunctata performing defensive tasks will have relatively higher expression of JHbp and of for regardless of treatment. This study may help us understand the relation between hormones and behavior in social insects.