Apis mellifera cuticular hydrocarbons analysis in a foraging context.

MARÍA SOL BALBUENA; ANDRÉS GONZÁLEZ; WALTER M FARINA

Congreso; III Congress of the Latin American Association of Chemical Ecology (ALAEQ); 2014

ALAEQ

Introduction: When a honeybee (Apis mellifera) collects nectar with high sucrose concentration, it returns to the hive and dances vigorously to communicate the discovered food source. During this conspicuous display its body temperature rises, promoting the release of certain cuticular hydrocarbons (CHCs), which have been postulated as a relevant stimulus for inactive foragers. A rise in body temperature also occurs upon nectar collection and during food exchange (trophallaxis), and correlates with food profitability. We studied if CHC profiles are affected under different food quality contexts at three stages of the foraging cycle. Material and Methods: We trained a group of forager honeybees to an artificial feeder offering high or low levels of sucrose concentration (2 and 0.5 M). Bees were captured at different stages: at the feeding site, at the hive entrance, and during trophallaxis (inside the hive). Hive bees and foragers captured in empty feeders served as controls. The bees were sacrificed using CO2 and the CHCs were extracted in dichloromethane and analyzed by GC-MS. We identified 48 CHCs that were quantified relative to an internal standard, and statistically analyzed by Principal Component Analysis. Results: We found significant differences in CHCs of hive and forager bees, but not among forager bees in any of the phases of the foraging cycle or sucrose-concentration treatments. Our results are therefore not in line with previous studies reporting that four hydrocarbons, namely (Z)-9-tricosene, tricosane, (Z)-9-pentacosene and pentacosane, are produced in larger amounts by foraging bees advertising a profitable food source. Conclusions: Our results show that while CHCs of honeybees vary between castes, no obvious qualitative or quantitative changes in CHCs can be correlated with food profitability.