Although it is believed that internal nutrient sensors play important roles in feeding behaviors, their molecular and neural mechanisms underlying of the modulation of physiological status and cell growth are poorly understood. Using a Ca2+ imaging experiments with heterologous expression systems, we show that one of the gustatory receptors in the western honey bee Apis mellifera is selectively tuned to amino acids. Remarkably, we report that this gustatory receptor of the honey bee is highly expressed in hypopharyngeal gland, which plays a role in caste differentiation as well as royal jelly production and secretion. Knocking down this gustatory receptor gene reduces cellular pathways responsible for nutritional sensing such as mTOR signals in hypopharageal gland. Furthermore, the interfering expression of this gustatory receptor gene not only alters morphological changes and developmental retardation of the hypopharyngeal gland, but it also blocks cellular growth signals to induce autophagy. This new report indicates that internal sensing and downstream signals detecting nutrients is essential for honey bee to maintain the cellular growth and development of internal organs essential for caste development and maintenance of social structure in the honey bee.

• Je Won Jung(Biomodulation Major, Department of Agricultural Biotechnology, College of Agriculture & Life Sciences, Seoul National University)
• Hyung Wook Kwon(Biomodulation Major, Department of Agricultural Biotechnology, College of Agriculture & Life Sciences, Seoul National University)