Insects demonstrate an impressive repertoire of learned behaviors and are specifically suitable for studies on evolutionary processes because of their high fecundity and short life span. In this chapter I focus on the evolutionary processes that shape learning ability in insects on the relatively short-term evolutionary scale. For cognitive traits and behavior to evolve under direct natural selection the following requirements must be met: (1) variation in cognitive ability between individuals, (2) this variation is heritable, and (3) this variation is related to fitness (reproduction or survival) in specific environments. First, I describe natural variation in learning ability and how this variation can be maintained in natural populations. Second, I discuss work on heritability of cognition, as well as related studies on artificial selection and experimental evolution. Finally, I discuss the benefits and costs of learning in relation to fitness.

Decades of research contend with the notion that animals come prepared by evolution to learn about some stimuli and responses better than others. Biological preparedness – and contrapreparedness – can influence how potential information is acquired, processed, and used in decision-making. Theory predicts that preparedness is the result of patterns of reliability of stimuli in predicting reward across the evolutionary history of the lineage. The evolution of preparedness can be tested experimentally, and also by considering the natural history and the pattern of reliability of stimuli and rewards for a given species. We present predictions as well as explanations for how evolution can prepare animals to make choices about their environment. Why animals learn some things better than others is at the heart of what makes behavior adaptive and by working from relatively simple theory it is possible to directly test these hypotheses and analyze traits both underlying and evolving with prepared learning.