Royal Holloway University of London | Department of Biological Sciences
The Value of Memory
“Ecological intelligence” hypotheses posit that animal learning and memory evolves to meet the demands posed by foraging, and together with social intelligence and cognitive buffer hypotheses, provide a key framework for understanding cognitive evolution1–5. However, identifying the critical environments where cognitive investment reaps significant benefits has proved challenging6–8. Here, we capitalise upon seasonal variation in forage availability for a social insect model (Bombus terrestris audax) to establish how the benefits of short-term memory, assayed using a radial arm maze (RAM), vary with resource availability. Following a staggered design over two years, whereby bees from standardized colonies at identical life history stages underwent cognitive testing before foraging in the wild, we found that RAM performance predicts foraging efficiency – a key determinant of colony fitness – in plentiful spring foraging conditions, but that this relationship is reversed during the summer floral dearth. Our results suggest that selection for enhanced cognitive abilities is unlikely to be limited to harsh environments where food is hard to find or extract5,9–11, highlighting instead that the challenges of rich and plentiful environments, which present multiple options in short succession, could be a broad driver in the evolution of certain cognitive traits.