Structural and functional differences in the antennae of worker honey bees of Apis mellifera and Apis cerana.

Structural and functional differences in the worker bee antenna of two Apis species, A. mellifera and A.cerana. Je won JUNG, Kun woong PARK and Hyung Wook KWON WCU Biomodulation major, Department of Agricultural Biotechnology, College of Agriculture & Life Sciences, Seoul National University, Seoul, Republic of Korea Email: jjwf82@snu.ac.kr, kaneck@snu.ac.kr, biomodeling@snu.ac.kr Olfactory discrimination, perception and orientation play important roles for most insects. The complexity of olfactory systems in a given species may depend on its feeding ecology, diversity of pheromone communication and olfactory recognition, as well as utilizing chemical cues for orientation in the environment. The honeybee is a highly social insect and works together by a division of labor. To regulate the complex social interactions, honeybees have evolved an intricate system of special olfactory organs. To understand the differences of olfactory functional mechanism in honeybee antenna, structural and functional variations of worker bee antenna of two species, Apis mellifera and Apis cerana were compared using the morphological design, electrophysiological responses and proboscis extension reflexes (PER). We measured the number of sensilla present on the left and right antenna by scanning electron microcopy. Results show that putative olfactory sensilla(placodea, trichodea, basiconica) were significantly more abundant on the A.cerana antenna surface than on the A.mellifera antenna surface. Similarly, electroantennographic responses to various floral volatile compounds were higher in A.cerana antenna than A.mellifera antenna. In addition, PER results are slightly different in two species. These findings extend our understanding of honeybee olfactory system and the different behavioral traits between two species by antennae in response to various ecological and biological signals.