Using sensillum potential analysis to quantify pheromone sensing of the antennal sensilla of Apis florea Fabricius (1787), foragers and guards

Odor perception via the antennal sensilla in most honeybee species is poorly studied. We measured the antennal sensillum potential in response to Apis florea mandibular gland pheromone and showed that it is robust and reliable in forager and guard bees. Mandibular gland pheromone may be involved in signaling alarm or foraging resource depletion. Changes of antennal sensilla placodea potential of A. florea foragers and guards were measured after exposure to three concentrations of the synthetic pheromones, 2-heptanone and (Z)-11-eicosen-1-ol, using a potentiostat connected to an e-corder (ED401) with microelectrodes. The resting sensillum potential of A. florea foragers and guards were -55.37 +/- 3.44 and -52.85 +/- 5.34 mV, respectively. The sensillum potential of bees exposed to 1.0%, 5.0% and 10.0% (Z)-11-eicosen-1-ol were -23.35 +/- 0.98, -16.78 +/- 1.94 and -24.24 +/- 820 mV, respectively, in foragers, and -21.95 +/- 3.21, -21.42 +/- 4.73 and -13.54 +/- 4.16 mV, respectively, for guards. Exposure of bees to 1.0%, 5.0% and 10.0% 2-heptanone induced sensillum potentials of -10.64 +/- 2.44, -4488 +/- 2.41 and -48.84 +/- 4.40 mV, respectively, in foragers and 15.85 +/- 9.38, -25.48 +/- 1.43 and -15.52 +/- 6.61 mV, respectively, in guards. The highest sensillum potential was recorded in foragers exposed to 1.0% 2-heptanone. In general, except for the response to 1.0% 2-heptanone, the sensillum potentials of all bees to (Z)-11-eicosen-1-ol were higher than that of 2-heptanone. These results show that A. florea antennal sensilla in foragers and guard bees exhibit a stronger response to (Z)-11-eicosen-1-ol as compared to 2-heptanone. Our results also provide useful comparative data to explore olfactory perception in non-model honey bee species. (C) Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society, 2010. Published by Elsevier B.V. All rights reserved.