Rôle de la sélection intersexuelle dans l’évolution de la cognition mâle et femelle : approche observationnelle et théorique

Choosing a mate is an important decision for an animal. Because this decision significantly affects an individual’s reproductive success, it must base its choice according to different traits that reflect the quality of potential mates. Recently, a particular attention has been given to cognitive traits in mate choice context. Indeed, the ability to perceive, integrate, memorize and use the information available in the environment allows individuals to act properly when facing a problem and to adjust their behaviours accordingly. Given that females could benefit from choosing males capable of responding to environmental changes, those with good cognitive abilities should have privileged access to females in mate choice contexts. Some evidence supports this idea by revealing positive relationships between males’ cognitive abilities and their mating and reproductive success as well as female mating preference for male cognitive abilities. However, these results stay contrasted, particularly in non-human animals for which the importance of mate choice in the evolution of cognition is still not clearly defined. The objective of my PhD was to explore the role of mate choice in the evolution of male and female cognition by combining an observational approach using a monogamous bird species and a theoretical approach using an agent-based model. Specifically, by running laboratory experiments on zebra finches (Taeniopygia guttata), I tested whether females demonstrated a mate preference for males able to adjust their foraging behaviour following an environmental change. Then, I investigated whether females, depending on their own cognitive abilities, demonstrated a mate preference for better performers in four different psychometric tests. I finally explored the relative role of natural and sexual selection by simulating the evolution of cognition under different environmental scenarios. The results of this PhD project revealed that zebra finch females preferred males exhibiting greater behavioural plasticity in their foraging tactic use as well as males performing better in several cognitive tasks. However, females’ preference for cognitive abilities was not unanimous but depended on females’ own abilities to perform in these tasks. At the evolutionary scale, intersexual selection through mate choice changed the evolutive patterns observed under natural selection alone. In fact, intersexual selection promoted good cognitive abilities under most favourable environments but maintained cognitive diversity under the harsher ones. Taken together, these results suggest that mate choice plays an important role in the evolution and maintenance of cognitive diversity within populations. Nevertheless, the evolutive consequences of mate choice on individual cognitive abilities should depend on i) the adaptive value of mating with a male with better performance, and thus, on the cognitive ability considered, ii) the female characteristics and iii) the local environment during mate choice.

Keyphrases: intersexual selection, cognitive abilities, sexual preference, cognitive diversity, Zebra finch, agent-based model