BIOLOGY, GENOMICS, AND INTEGRATED PEST MANAGEMENT OF INVASIVE ANTS
Location: Imported Fire Ant and Household Insects
Title: The role of tyramine and octopamine in the regulation of reproduction in queenless worker honeybees
Submitted to: Naturwissenschaften
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 13, 2011
Publication Date: December 29, 2011
Citation: Salomon, M., Malka, O., Vander Meer, R.K., Hefetz, A. 2011. The role of tyramine and octopamine in the regulation of reproduction in queenless worker honeybees. Naturwissenschaften. 99:123-131.
Interpretive Summary: Honey bees, like other social insects, use pheromones to regulate many critical activities relative to reproduction and worker division of labor. Understanding the physiological underpinnings of these processes can help manipulate hive dynamics, identify developing problems, and provide a model social insect system. Scientists from the Imported Fire Ant and Household Insect Unit at the Center for Medical, Agricultural and Veterinary Entomology, USDA, ARS, Gainesville, FL and from the Department of Zoology, Tel Aviv University, Tel Aviv, Israel, and the Department of Entomology, Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel have investigated the effect of two biogenic amines, octopamine (OA) and tyramine (TA) oral treatments on the propensity of treated bees to become reproductively dominant and produce queen-like pheromones in Dufour’s and mandibular glands. The results suggest that TA induces reproductive division of labor, while OA treatment results in caste differentiation of workers to foragers and nurses. These results provide another step forward in our understanding the complex physiological processes involved in honey bee pheromone production and behavioral consequences. Also, the work contributes to a general social insect framework that will accelerate research in other social insects, such as the economically important fire ant.
In honey bees, workers under queenless condition compete for reproduction and establish reproductive dominance hierarchy. Ovary activation is generally accompanied by the expression of queen-like pheromones. Biogenic amines (BAs), in particular dopamine, are believed to be involved in this process by regulating ovarian development. However, the role of BAs in establishing reproductive dominance or their effect on queen-like pheromone production was not investigated. Here, we explored the effect of octopamine (OA) and tyramine (TA) oral treatments on the propensity of treated bees to become reproductively dominant and produce queen-like pheromones in Dufour’s and mandibular glands. One bee in a pair was treated with either OA or TA while the other was fed sugar solution. TA was found to enhance ovary development and the production of esters in the Dufour’s gland and 9HDA (queen component) in the mandibular glands, thus facilitating worker reproductive dominance. OA, on the other hand, did not enhance ovarian development or ester production, but increased the production of 10HDA (worker major component) in the mandibular glands of their sugar-paired mates. OA is known to induce foraging behavior by workers, while increased production of 10HDA characterizes nursing workers. Therefore, we suggest that TA induces reproductive division of labor, while OA treatment results in caste differentiation of workers to foragers and nurses.