Intrasexual competition is ubiquitous in nature. In males, such competition for mates can lead to the evolution of conspicuous and costly morphological traits. However, competition through social interactions can
also occur for resources other than mates (such as food) and has been termed as social selection or social competition. Social competition in females, though not as conspicuous as that in males, may be widespread and is understudied. It can have important evolutionary consequences for individual phenotype and on the genetic and social structure of a population. Most of our understanding of traits involved in intrasexual competition comes from studies of males and less is known about social competition in females. Individuals can compete using physical fights. They are extremely costly and less common in females than in males, because of the inherent differences life histories of the two sexes. However, there are various alternatives to physical fights, an important one being
signalling and displays.
I propose to study intrasexual competition in females in a wild population of the Peninsular rock lizard* (Psammophilus dorsalis),* using a combination of observational and experimental approaches. These lizards can be easily be marked and followed over their lifetime. Preliminary work shows that females display towards other females and they vary in their display rates, using which they appear to compete among themselves for establishing and maintaining territories. Females also vary in their responses to a simulated intrusion. Thus, this study system is ideal for examining social competition in females.
This study will focus on the adaptiveness of signalling and aggression in females and examine differences between the sexes in these behavioural traits. I first plan to study territoriality (an outcome of competition) in females and compare patterns with those of males. I will also characterise physical features of territories to quantify the resources that might be under competition. I then propose to examine signalling and aggression over female lifetimes and study the factors influencing variation in these traits. I also plan to study the relationship between signalling and reproductive success in females. Finally, I propose to compare social signalling in intrasexual competition between males and females of *P. dorsalis*.