Does Brain Size Help Bees Adapt to Urban Environments?

In a new study published in Biology Letters, Lanuza et al assess whether brain size, relative to body size, helps bee species adapt to human-made and rapidly changing environments.

The role of pollinators is fundamental to the functioning of ecosystems. Rapid and widespread changes to the habitats of pollinators represents a major threat to individual species as well as entire ecosystems. However, as noted in this new study, not all pollinators are negatively affected by human-driven habitat change; some species are able to find and use appropriate resources in urban environments to survive.
The reason why some species survive in these environments while others struggle remains unknown.

One theory, called the cognitive buffer hypothesis, suggests that species with larger brains may be more capable of modifying behaviours to allow them to adapt to changes in their habitats. It is this hypothesis that Lanuza et al tested by measuring the brain size of 89 bee species and evaluating the degree to which they occupy different types or habitat.

Their analyses showed that bee species with larger brains relative to their body size were more likely to occupy urban habitats compared with species typically found in more natural habitats, such as in forests. They also found that bees species typically found in urban environments had larger overall body sizes, and therefore larger absolute brain sizes.

Their results importantly provide the first empirical support for the cognitive buffer hypothesis in invertebrates, and provide insights into how different species of bee may be impacted by human-made environmental stresses.