The Influence of Gustatory and Olfactory Experiences on Responsiveness to Reward in the Honeybee

RAMIREZ, GABRIELA; MARTÍNEZ, ANDRÉS; FERNÁNDEZ, VANESA; CORTI BIELSA, GONZALO; , FARINA WM

PLOS ONE

PUBLIC LIBRARY SCIENCE

Año: 2010 vol. 5 p. 1 - 12

1932-6203

Background: Honeybees (Apis mellifera) exhibit an extraordinarily tuned division of labor that depends on age polyethism.This adjustment is generally associated with the fact that individuals of different ages display different response thresholdsto given stimuli, which determine specific behaviors. For instance, the sucrose-response threshold (SRT) which largelydepends on genetic factors may also be affected by the nectar sugar content. However, it remains unknown whether SRTsin workers of different ages and tasks can differ depending on gustatory and olfactory experiences.Methodology: Groups of worker bees reared either in an artificial environment or else in a queen-right colony, wereexposed to different reward conditions at different adult ages. Gustatory response scores (GRSs) and odor-memory retrievalwere measured in bees that were previously exposed to changes in food characteristics.Principal Findings: Results show that the gustatory responses of pre-foraging-aged bees are affected by changes in sucrosesolution concentration and also to the presence of an odor provided it is presented as scented sucrose solution. In contrastno differences in worker responses were observed when presented with odor only in the rearing environment. Fastmodulation of GRSs was observed in older bees (12–16 days of age) which are commonly involved in food processing taskswithin the hive, while slower modulation times were observed in younger bees (commonly nurse bees, 6–9 days of age).This suggests that older food-processing bees have a higher plasticity when responding to fluctuations in resourceinformation than younger hive bees. Adjustments in the number of trophallaxis events were also found when scented foodcirculated inside the nest, and this was positively correlated with the differences in timing observed in gustatoryresponsiveness and memory retention for hive bees of different age classes.Conclusions: This work demonstrates the accessibility of chemosensory information in the honeybee colonies with respectto incoming nectar. The modulation of the sensory-response systems within the hive can have important effects on thedynamics of food transfer and information propagation.