Habitat stability and predation pressure influence learning and memory in populations of three-spined sticklebacks

Learning and memory enable animals to adjust their behaviour in variable environments. Not all habitats vary to the same extent, and thus different environments can affect learning and memory in different ways. Habitat stability is one of numerous environmental variables proposed to influence what animals learn, but it is unlikely to act alone. To investigate how multiple variables affect learning and memory behaviour, we compared spatial learning and memory in three-spined sticklebacks from four ponds (stable habitat) and four rivers (unstable habitat) of varying predation pressure. Contrary to initial predictions, river fish had longer memory duration (>1 week) than pond fish (<1 week). Learning rate was affected by an interaction between habitat stability and predation pressure, with low-predation river populations learning faster than high-predation river populations. These results show that learning and memory can be affected in different ways by contrasting ecological factors and that multiple ecological factors can interact to shape learning and memory, thus emphasizing the importance of considering multiple ecological variables when investigating behaviour.