Associative learning during early adulthood enhances later memory retention in honeybees.

ARENAS, ANDRÉS; FERNÁNDEZ, VANESA; FARINA, WALTER M

PLOS ONE

PUBLIC LIBRARY SCIENCE

Año: 2009 p. 804 - 812

1932-6203

Background: Cognitive experiences during the early stages of life play an important role in shaping the future behavior inmammals but also in insects, in which precocious learning can directly modify behaviors later in life depending on both thetiming and the rearing environment. However, whether olfactory associative learning acquired early in the adult stage ofinsects affect memorizing of new learning events has not been studied yet.Methodology: Groups of adult honeybee workers that experienced an odor paired with a sucrose solution 5 to 8 days or 9to 12 days after emergence were previously exposed to (i) a rewarded experience through the offering of scented food, or(ii) a non-rewarded experience with a pure volatile compound in the rearing environment.Principal Findings: Early rewarded experiences (either at 1–4 or 5–8 days of adult age) enhanced retention performance in9–12-day-conditioned bees when they were tested at 17 days of age. The highest retention levels at this age, which couldnot be improved with prior rewarded experiences, were found for memories established at 5–8 days of adult age.Associative memories acquired at 9–12 days of age showed a weak effect on retention for some pure pre-exposed volatilecompounds; whereas the sole exposure of an odor at any younger age did not promote long-term effects on learningperformance.Conclusions: The associative learning events that occurred a few days after adult emergence improved memorizing inmiddle-aged bees. In addition, both the timing and the nature of early sensory inputs interact to enhance retention of newlearning events acquired later in life, an important matter in the social life of honeybees.