Circadian modulation of colour memory in honeybees (Apis mellifera)

Foraging is an essential part of survival in homebees (Apis mellifera). Bees use a series of memories to keep track of the varying foraging environment. We investigated the colour memory retrieval in bees and tested the acquisition, retention and integration. We found that the bees were fast in acquisition and learnt the task from 5th trial onwards. The bees were also able to retain the memory after a delay of 24 h. We then tested how bees integrate two conflicting tasks. In the first task (phase 1), each bee had to learn one colour for 20 trials, and in second task (phase 11), they had to learn anther colour in 10 trials. After training, each bee was tested immediately and after a delay of 10 min, 22 and 24 h. The delay test time (22 and 24 h) corresponded to the training time of the previous day. We proposed three hypotheses on the integration of multiple memories 1) Memory based on recency 2) Memory based on elapsed time 3) Memory based on circadian time. The results support the hypothesis that memory retention in bees is based on circadian time.