Overnight memory retention of foraging skills by bumblebees is imperfect

Tamar Keasar, Uzi Motro, Yoav Shur, Avi Shmida

Research output: Contribution to journalArticlepeer-review


Newly emerged bees learn to forage more efficiently as they gain experience. To test the hypothesis that foraging efficiency would increase as bees gain experience during the day, but would decrease after a night, owing to loss of memory, naive Bombus terrestris bumblebees were allowed to forage on two clusters of artificial flowers of unequal profitabilities during 3 consecutive days. Nectar intake rate, percentage of visits to the more profitable cluster, probing time and time intervals between visits were computed as measures of the bees' foraging efficiency. Nectar intake rates increased significantly during the day, and decreased partially but significantly after a night. They varied greatly between bees. The bees did not show a preference for one of the clusters at the onset of the experiment, and none consistently increased their visits to the more profitable cluster during single observation days. Most individuals did not visit the higher-reward cluster exclusively by the end of the third day. However, visits to the higher-reward cluster did increase significantly when the first day of observation was compared with the third day. Preference for the higher-reward cluster increased after the first night but decreased significantly after the second night. Probing time and inter-visit intervals decreased significantly during observation days, and increased significantly after a night. The results indicate that bees learn to approach and probe flowers faster, as they gain experience, during a foraging day, but that these skills are partially forgotten overnight. Patch preference is formed more slowly. Once formed, it is also weakened overnight. Such partial forgetting may aid the bee in reacting quickly to overnight changes in resource profitability by modifying flower choices and handling techniques.

Original languageEnglish
Pages (from-to)95-104
Number of pages10
JournalAnimal Behaviour
Issue number1
StatePublished - Jul 1996
Externally publishedYes

Bibliographical note

Funding Information:
The study was supported by the Interuniversity Ecology Foundation, Israel. We are grateful to A. Bertsch, K. Waddington and R. Menzel for their guidance and advice in development and establishment of the bee laboratory. K. Waddington, S. Ellner, R. Menzel, H. Dobson and two anonymous referees made important comments on early versions of the manuscript. We thank A. Werechson and Z. Sagiv for the design and construction of the electronic flowers, and E. Rashkovits for help with observations.

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


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