Relational similarity in wild bumblebees: the role of spatial alignment complexity.

Being able to abstract relations of similarity is considered one of the hallmarks of human cognition. Importantly, previous research has shown that other animals-both vertebrates (e.g., primates) and invertebrates (e.g., bees)- are capable of spontaneously attending to relational similarity in spatial mapping tasks. These tasks require individuals to find a reward in an array of, for example, three objects, after observing a reward being hidden in a different array of three objects. Studies with primates have shown that performance in this type of task is influenced by the distribution of the objects in the arrays. Here I investigated whether wild bumblebees' relational abilities are also affected by the spatial complexity of the arrays (i.e., three horizontally aligned stimuli). In Experiment 1, bees were presented with two arrays separately: in one condition, the arrays were placed next to each other (forming a line) and in the other, the arrays were placed in two different rows. In Experiment 2, the two arrays were also placed in two rows, but the rows were misaligned. Bees succeeded in both Experiments and in the three different distributions of the arrays. The results suggest that bees were comparing the two arrays and recognized the common relational features in both arrays. Studies like the ones presented here highlight the importance of studying social insects to understand the evolution of cognition.