Research on intrasexual competition has largely focused on males. Competitive signalling and aggression strategies used by males have been widely studied. It is increasingly recognised that intrasexual competition may be common among females too; but our understanding about female competitive strategies is largely restricted to eusocial insects and cooperative breeding societies. Unlike males who compete to mate, females in polygynous systems rarely get large immediate fitness gains through intrasexual competition, since they are limited by the time it takes to successfully produce offspring. Additionally, because of their investment in young, the costs of overt competition, such as conspicuous signalling and physical aggression, are expected to be relatively high for females. Accordingly, females are expected to use inconspicuous broadcast displays, should be more sensitive to the perceived threat and invest in competitive signalling and aggression only when the threat of a competitor is high. We tested these hypotheses by observing P. dorsalis individuals in the wild and simulating intruder threat at multiple threat levels on their territories. Analysis revealed that females use relatively less conspicuous behaviours as broadcast displays. While both sexes increase signalling in high threat conditions as compared to low threat conditions, females show a substantially larger increase than males. Sex differences in physical aggression were also seen. Here, I discuss the implications of these sex differences in signalling and aggression in intrasexual competition in a polygynous tropical agamid.