An overview of geographic variation in the life history traits of the tropical agamid lizard, Calotes versicolor

Life history theory seeks to explain patterns of variation among geographically widespread populations of same species to understand their ecology and adaptations. To date, very few attempts have been made to review and compare life history traits of tropical reptiles, especially those that inhabit the Asian continent. Among tropical reptiles, the agamid lizard Calotes versicolor is widespread, extensively studied and thus ‘tailor made’ to understand geographic variation if any. Therefore, in this review, life history traits of C. versicolor are compared to understand variation in life history with reference to their geographical distribution. The examination of C. versicolor populations across its geographic range demonstrates considerable variation in some of the life history traits but not in all. For example, there is no sexual size dimorphism at hatching in one population but it is apparent in another. Body size, mass, reproductive output, influence of incubation thermal regimes on eggs and embryos differ between the populations. There is a trade-off between clutch size and egg size in one population but egg size is optimised in another. Lizards that belong to one population mature at a smaller size but at the same age compared to another population. Also, embryos exhibit high thermal tolerance in one population compared to another. These emergent life history patterns from the comparisons are discussed in light of traditional as well as recent views and theories of life history in reptiles.