The social organization of foraging processes is a principal key to the ecological success of eusocial
insects. Floral odours brought back to the colony by successful foragers are important sources of information underlying an individual’s decision about which resource to collect. Food-source-naïve individuals memorize and use this olfactory information when searching for food in the field. Odour
familiarization as mechanism underlying the coordination of foraging processes has received little
attention so far. Here, we asked whether and to what extent foraging decisions of stingless bees, Melipona scutellaris, are influenced by preceding unrewarded olfactory experiences. In a classical conditioning assay (proboscis extension reflex, PER, assay), foragers were exposed to a scented airflow, during
which they either received (experimental group CS þ) or did not receive (experimental group CS-) a sugar
solution as reward. Subsequently, bees of both experimental groups were introduced into an arena where
they could choose between two scented feeders, one of which carried the odour used during the PER
assay. Independently of whether foragers had received a sucrose reward during scent exposure, between
70% and 75% of the individuals chose the food source that carried the conditioned odour in the choice
arena. Bees from the control groups (harnessed or not; no scent exposure), by contrast, showed no
preference for either of the two feeders. These findings point to the importance of preceding olfactory
experiences for the food choice of M. scutellaris and suggest that both associative learning during
trophallaxis as well as familiarization may influence to a similar extent the foraging decisions of these
bees in natural settings.