Time-course of memory formation differs in honey bee lines selected for good and poor learning

Abstract

Six lines of the honey bee Apis mellifera capensis were selected for good and poor learning, and compared with respect to the time-course of their memory after a single learning trial to an odour stimulus (geraniol). The good learners showed the well known bi-phasic time-course with a high rate of conditioned responses immediately after learning, followed by a reduction 1–3 min later and a consolidation into a long-term memory after an interval longer than 5 min. Poor learners differed significantly with respect to their consolidation period and the initial high response rate. The initial period (of less than 1 min) is controlled not only by the associative memory of the learning trial but also by a sensitizing effect of the sucrose stimulus which was used as an unconditioned stimulus. It is concluded that the lines selected for learning performance differ with respect to the establishment of a long-term memory trace. As in Drosophila learning mutants, differences between good and poor learners are also affected by non-associative processes involved in sensitization.