Skeletal morphology is a classic candidate for ‘plasticity-led’ evolution. Our new paper in eLife tests the idea that such ‘plasticity-led’ evolution has occurred in the adaptive radiation of Anolis lizards on the Greater Antilles.
In her study, Nathalie quantified the morphological divergence between ecomorphs on the four Greater Antillean islands. She then compared this to the morphological changes induced by microhabitats that promote climbing or running. It turns out that divergences between ecomorphs have occurred in parallel on the different islands. However, the divergence between ecomorphs was not aligned with plastic responses. In addition, plasticity differed between species, making it too transient to exercise a persistent effect on adaptive diversification of the locomotor skeleton.
At first sight, this may appear to be a major blow to the plasticity-first hypothesis. And in some ways it is. However, rather than showing that morphological plasticity has been rather inconsequential in this adaptive radiation, Nathalie’s discussion of her results helps us sharpen our theories about the relationship between plasticity and evolution – something that we and others have argued is necessary. Step by step, this brings us one step closer to actually understanding how development shapes evolution.