Early appetitive experiences enhance long-term memory retention in young bees.

A. ARENAS, V. M. FERNANDEZ & W. M. FARINA

Einsiedeln, Suiza

Conferencia; European meeting of PHD students in Evolutionary Biology; 2008

During a short period of early life, the presence or absence of a particular sensory experience could permanently shape animals? behavior. These critical periods exist for many functions including language in humans, song in birds, orientation in salmon and vision in mammals and insects. In honeybees, it was recently showed that early olfactory experiences have important consequences on the odor-mediated behaviors of foraging-age bees (since 17 days old) as odor information could be retained from five days after emergence. Moreover, honeybees showed better retention if they acquired the odor information of the food at 5-8 days than at 9-12 days of age. Here, we tested if the early offering of scented-food enhance the ability to retain new associative events occurred at a later time. Then, groups of worker bees that were olfactory stimulated at 5-8 or 9-12 days old were also offered a second rewarded odor (non-tested odor) at an earlier time, 1-4 or 5-8 days old respectively. The strength of the retained-odor information was evaluated in a Pavlovian context, the proboscis extension response paradigm. Results showed that when 9-12-day-old conditioned bees had been also stimulated at 5-8 days old with a second rewarded odor, better retention to the first odor was found at 17 days old in comparison with bees conditioned at 9-12 days of age only. The fact that early experiences facilitate memory retention at a later time provides evidence of a critical period in honeybees. Results are discussed in terms of the development and maturation of functional properties of the bee brain which are strongly influenced by experiences and environmental conditions at early ages.