Cooperation, competition and the persistence of behavioural diversity

Alongside the wide diversification of behaviours we observe across species, understanding how behavioural variation persists in populations is a central question in evolutionary biology. In this talk, I present research across three animal systems that share a common thread: the coexistence of alternative behavioural strategies. I draw on these systems to explore how sexual selection drives the diversification of courtship displays across and within species, and how trade-offs between cooperation and competition allow seemingly suboptimal strategies to persist alongside dominant ones. I then extend this framework beyond the context of sexual selection, examining how individual and group-level dispersal strategies coexist, vary across populations, and may be shaped by environmental conditions. Together, these systems reveal that behavioural variation is not noise but an evolutionarily meaningful outcome of selection acting on social context and individual trade-offs. Understanding when and why the "suboptimal" strategy persists is key to understanding behavioural evolution.