Early Olfactory Experience within an Appetitive Context in Honeybees, Apis mellifera L.

A. ARENAS; WM. FARINA

Denmark

Congreso; The 7th Congress of the International Society for Neuroethology.; 2004

Honeybee foragers easily adjust their olfactory memories to successive experiences such as changes in the floral availability (Menzel, 1999). This plasticity allows them to shift from one memory to another when the situation calls for it, which is one of the main elements of their adaptability. Animals can behave by using reference information obtained a long time before, and at any particular moment information is evaluated according to general controlled internal conditions, context dependence and the meaning of the new information presented (Menzel, 1999). Foragers bees have the ability to forage using information gained within and without the hive context (V.Frish, 1967 and Wenner et. al. 1969). Even more it could be possible that not only foragers obtain information but pre-foragers too. Under natural conditions, adult worker bees' progress through a succession of defined tasks, including feeding immature stages, comb maintenance and wax and nectar processing, reaching foraging activities at the age of 17 days old (Fewell & Bertram, 2002). Feeding larvae and processing nectar (in early stage development) and fulfill activities as nectar receivers (close foraging stage) may cause the acquirement of information about nectar?s properties and constrains. Stimuli or experiences suffered in the hive during pre-foraging stages are essential for the development of brain morphology, which is surely necessary to the maturation of learning ability (N. Ichikawa, 2002). A period from 3 days before to 4-8 days after emergence appears to be critical, the olfactory system remains very flexible and susceptible to environmental changes (Masson et. al.,1993). Important neuroanatomical differences occur in the antennal lobes from its emergence to 4 days old. Using EAGs, physiological recordings determined that sensorial responses to pheromones vary as adult bees aged (Robinson 1987). Pollenkitt chemical in intimate contact with the bee through out its development, allowing imprinting to occur (Dobson, 1987). Further understanding comes from experiences with Drosophila, (A. Barron et. al. 1999) which suggested that exposure during the early adult stage was more important than larval and pupal stage exposure in shaping adult behavior. Jaisson (1980) also demonstrated that, during the first days of imaginal life, early experience could induce an environmental preference using sub-family Formicidae. Lasius niger could do an early learning for odours related to foraging resources (Beckers et al. 1994). It would be reasonable to think that pre-foraging olfactory experiences could give place to memory templates that might later be stronger than memories established during the actual foraging activities. These early experiences would bias, in the long term, the foraging bee behavior. We hypothesize that these pre-foraging experiences could conform long-term olfactory memories if acquired in an appetitive context, where the scent occurs together with a reward that circulates among workers inside the hive. Gerber et. al. (1995) and Sandoz et. al. (1999) studied the information transfer between operant and Pavlovian conditioning. They showed that information could be transferred from one paradigm to another and suggested that both stimulus-reward associations may be of the same type. Although Sandoz studied bees subjected to early olfactory experience, they weren?t presented in an appetitive context. On the other hand Gerber?s experience was done in an appetitive context, but he didn?t study pre-foragers bees. Retention of this learning might allow adults to locate foraging position quickly. Exposure to the conditioning stimulus in the early imaginal stage might be enough to change behavior.