Pollen foragers rely on preferences for pollen aromas but on learning of other floral cues to deal with pollen sources.

A. ARENAS; W.M. FARINA

Congreso; 42nd International Apicultural Congress; 2011

Honeybees (Apis mellifera) often exhibit a learned odor-preference for flowers that has previously provided nectar as a reward. Foragers use odors to distinguish rewarding from non-rewarding flowers which also serve as guiding cues for successive foraging flights. However, very little is known about behavioral plasticity in bees that do not forage for nectar but other flower resources like pollen. Nectar foragers lap nectar from flowers and store it internally and could even feed on it if necessary. Pollen foragers, instead, collect pollen externally and rarely consumed it. Despite differences in their collecting behaviors, the question whether nectar and pollen foragers are each using the same learned-based mechanism to improve foraging efficiency remained untested. In an attempt to understand the way foragers use i) pollen aromas itself and ii) floral olfactory cues associated to pollen sources to improve foraging task, we studied the decision-making process under different experimental situations. Here we shall demonstrate that pollen foragers have preferences for pollen aromas which are stronger than in nectar foragers, a search image that is acquired at early stages. Despite preferences for pollen aromas, foragers do also learn neutral odors associated to pollen in a natural gathering context, quantified as correct landing responses in a two-scented-feeder situation. Moreover, olfactory memories acquired with pollen as a reward can be transfer to other context such as odor preferences in a Y-maze but failed to be recalled in the proboscis extension responses paradigm. At last we showed that learned odors were able to trigger vector memories when retrieved inside the hive which induced to re-visit depleted past profitable foraging sites. Then even when foragers rely on preferences for pollen aromas to be attracted to pollen sources, learning of other cues may still be important when dealing with flowers that are unique to time and place.