Honeybees likely use relational information to decide which flowers are optimal for foraging nectar. For instance, laboratory research has shown that the bees are able to discriminate between sizes of stimuli as well as their relative positions and can apply learned rules to make decisions. Such experiments have typically presented bees with a choice among simultaneously encountered images or objects. Scarlett Howard at RMIT University in Australia, in partnership with colleagues at Australia's University of Melbourne and Monash University as well as the Université de Toulouse in France, wanted to find out whether honeybees trained to prefer a certain relative size of artificial flower (larger or smaller) could apply those preferences to flowers presented one after another – in other words, whether the bees could remember the flowers they saw previously in making decisions about subsequent flowers. The research team also wanted to investigate whether honeybees could exercise their size preferences when encountering flowers of a new size outside of their training range.

To address their research questions, the scientists first trained two groups of honeybees to prefer either larger or smaller artificial flowers presented in a viewing chamber that only allowed the bees to view one flower at a time (to prevent simultaneous size comparisons). Offering the bees a choice of four flowers – two identical larger flowers and two identical smaller flowers – the team allowed the bees to select a flower by landing on a small platform beneath. The bees were rewarded with a sugary substance when they landed by the flower of the relative size that they were being trained to prefer, or were discouraged from landing with a foul-tasting substance when they selected the wrong flower. After training, the bees were reintroduced into the chamber for the first test, in which they were asked to identify the relative flower size (larger or smaller) that they had just been trained to choose, without the benefit of a reward, to prove that they could select the correct flower size. Then, in a separate trial, the bees were given choices between flowers that were completely outside of the size ranges they had seen before, to assess whether they could apply their learned size preferences to unfamiliar flowers and select either the larger or the smaller of the two flower sizes according to the size they had learned to prefer during training.

Howard and her colleagues discovered that the bees were able to learn to choose flowers based on their relative sizes, and they were also able to correctly choose between flower sizes that were outside of the size range they had encountered previously. These results indicate that the honeybees are able to remember what previously viewed flowers looked like, and can compare the remembered images with successive flowers in order to make informed choices. The ability of the bees to discriminate between flowers of new sizes also shows that they are able to extrapolate learned preferences to novel situations.

In all, the study suggests that honeybees have considerable cognitive ability and are able to hold information in their working memory to aid in decision-making processes. Clearly, honeybees are not simply bumbling about when foraging for food; rather, their brains are buzzing as they choose the perfect flower.

S. R.
A. G.
Free-flying honeybees extrapolate relational size rules to sort successively visited artificial flowers in a realistic foraging situation
Anim. Cogn.