Mismatches between phenotype and environment shape fitness at hyperlocal scales (Agama atra)

In the era of human-driven climate change, understanding whether
behavioural buffering of temperature change is linked with organismal
fitness is essential. According to the “cost-benefit” model of
thermoregulation, animals that live in environments with high frequencies
of favourable thermal microclimates should incur lower thermoregulatory
costs, thermoregulate more efficiently and shunt the associated savings in
time and energy towards other vital tasks such as feeding, territory
defence, and mate acquisition, increasing fitness. Here, we explore how
thermal landscapes at the scale of individual territories, physiological
performance, and behaviour interact and shape fitness in the southern rock
agama lizard (Agama atra). We integrated laboratory assays of whole
organism performance with behavioural observations in the field,
fine-scale estimates of environmental temperature, and paternity
assignment of offspring to test whether fitness is predicted by territory
thermal quality (i.e., the number of hours that operative temperatures in
a territory fall within individual’s performance breadth). Male lizards
that occupied territories of low thermal quality spent more time
behaviourally compensating for suboptimal temperatures and displayed less.
Further, display rate was positively associated with lizard fitness,
suggesting that there is an opportunity cost to engaging in
thermoregulatory behaviour that will increase as climate change
progresses.