Organisms can cope with novel challenges by modifying their behaviour, physiology,
morphology and cognition. In today’s world, however, anthropogenic activities, such
as urbanisation, rapidly and dramatically change natural environments, altering
habitats as well as shifting resources and predator communities. To understand the
impacts of urbanisation on phenotypic traits, I studied the social and survival
strategies of the Indian rock agama, Psammophilus dorsalis. Using a combination of
field and laboratory-based experiments, I examined differences in gross morphology,
signal-receiver dynamics in communication, anti-predator strategies, stress
physiology, and spatial learning. Social interactions in this species involve rapid
physiological colour changes and behavioural displays. My work shows that colour
patterns are diametrically different between courtship and aggressive interactions;
and that urban males express lower colour contrast and were slower to change colours
than rural males. Using robotic lizard stimuli, I found that receiver responses
match population-specific intensity of male signals. Escape strategies of males, but
not females, also differed between urban and rural populations, such that urban
males were more tolerant of simulated predator attacks than rural males. As expected
from their cryptic body patterns, females regardless of habitat, relied more heavily
on crypticity rather than flight to minimize predation risk. Urban males also had
stronger cognitive skills, as spatial learning and reversal learning was faster than
in rural males. Along with these phenotypic shifts, stress physiology was also
affected, as urban males had significantly higher circulating corticosterone levels
than rural males. In sum, differences in these phenotypic traits between urban and
rural populations suggest human-induced changes in selective pressures that support
shifted survival and reproductive strategies.