Sexual selection can favour the evolution and maintenance of highly elaborate traits in males. In many species, males show multiple morphological and behavioural-display traits. Though many studies have examined the role of sexual selection in shaping male display traits, they are typically done over a short part of the animal’s lifespan, and often in captive or semi-natural conditions. Patterns of variation in multiple display traits over the lifetime of individuals under natural ecological and social contexts are still not well understood. Apart from traits related to mate-acquisition, sexual selection can also influence behavioural traits involved in other aspects of an animal's ecology. Traits related to animal personality form one such set of traits. Research on consistent between-individual differences (called repeatability) in various behavioural traits related to personality is rapidly expanding. However, we know relatively little about patterns in repeatability in traits over a lifespan, especially in the wild, and the role of sexual selection processes in maintaining repeatability. With the motivation of studying sexual selection in the wild, I focus on examining the influence of sexual selection on male mating behaviour and personality in male Peninsular Rock Agama (*Psammophilus dorsalis*).

I first describe the natural history of the breeding system of this species. By following uniquely tagged individual lizards over their lifetime, I describe the breeding phenology and mating system of P. dorsalis. I then examine variation in multiple behavioural traits of breeding males and the influence of social context on these traits. My findings show that certain behavioural traits of displaying males show a strong pattern of covariation, are mostly directed towards females, and appear to carry predation costs. I also examine the relationship between these traits and indices of male mating success. To study the role of sexual selection in maintaining animal personality, I first quantified repeatability in risk-aversion behaviour. There is significant repeatability both in the short-term and over the lifespan of males. Finally, I examined the role of sexual selection by testing whether risk-responsiveness occurred in a behavioural syndrome with male display traits. However, I did not find evidence for the existence of a behavioural syndrome (i.e correlation) in personality traits measured across the contexts of mating and risk-aversion. Through such long-term behavioural monitoring of individual lizards, this thesis contributes towards a better understanding of the influence of sexual selection on multiple display traits, and on patterns in repeatability in display traits and risk-aversion, over the lifetime of an individual in the natural context.