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

ARENAS, ANDRÉS; FARINA WM

Buenos Aires

Congreso; 42º Congreso Internacional de Apicultura Apimondia 2011; 2011

Apimondia

Pollen foragers rely on preferences for pollen aromas but on learning of other floral cues to deal with pollen sources Arenas, A.; Farina, W.M. Grupo de Estudio de Insectos Sociales, Departamento de Biodiversidad y Biología Experimental, IFIBYNE, CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina. Tel: (+5411) 4576 3445. aarenas@bg.fcen.uba.ar   Honeybees (Apis mellifera) often exhibit a learned odor-preference for flowers that provided nectar as 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 such plasticity in bees that forage for pollen. Nectar foraging bees lap and store nectar in their honey sacs, which allows feeding 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. This is a particularly interesting question since apparently there is no food reward within the pollen foraging event. In an attempt to understand the way bees use the pollen aromas itself as well as other olfactory cues associated to pollen sources, we studied the making-decision process involving in pollen gathering 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. On the other hand, foragers do also learn neutral odors associated to pollen in a natural gathering context, a response quantified as correct landings in a two-scented-feeder situation. Moreover, olfactory memories acquired with pollen as a reward were successfully recalled in an odor-choice test (Y-maze), but failed to be transferred to the proboscis extension responses paradigm. Finally we showed that learned odors delivered inside the hive triggered vector memories inducing bees to revisit depleted past profitable pollen sources. 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.