Male bumblebees perform learning flights on leaving a flower but not when leaving their nest

Abstract

Female bees and wasps demonstrate, through their performance of elaborate learning flights, when they memorise features of a significant site. An important feature of these flights is that the insects look back to fixate the site that they are leaving. Females, which forage for nectar and pollen and return with it to the nest, execute learning flights on their initial departures from both their nest and newly discovered flowers. To our knowledge, these flights have so far only been studied in females. Here we describe and analyse putative learning flights observed in male bumblebees, Bombus terrestris L. Once male bumblebees are mature, they leave their nest for good and fend for themselves. We show that, unlike female foragers, males always flew directly away from their nest, without looking back, in keeping with their indifference to their natal nest. In contrast, after males had drunk from artificial flowers, their flights on first leaving the flowers resembled the learning flights of females, particularly in their fixations of the flowers. These differences in the occurrence of female and male learning flights seem to match the diverse needs of the two sexes to learn about ecologically relevant aspects of their environment.