Evolution 2018 : Hurricane-Induced Habitat Destruction Could Mediate the Dewlap Color Polymorphism in Anolis distichus

The anole dewlap is a powerful visual signal to attract sexual partners and repel rivals and predators. The diversity of dewlap color has fascinated researchers for decades, environmental lighting and species competition being among the potential drivers of its evolution. At the Evolution meeting in Montpellier, Winter Beckles, PhD student at the University of Miami, presented his great study on the bark anole. Anolis distichus invaded Miami through multiple introductions events. Intriguingly, these little lizards occupy a range of habitats and present polymorphisms in their dewlap color within populations.

For his PhD, Winter and his colleagues measured the reflectance spectrum of the habitat and of the dewlap of 20 to 25 males per population. They found a strong positive correlation between the relative abundance of habitat UV light and the UV light reflected by the dewlaps. But that was before Hurricane Irma hit Miami in September 2017. And what a destruction it was: the trees, the canopy, the plants and by consequence the habitat lighting, were affected by this catastrophic event.

Despite the obvious negative consequences of the hurricane, this event gave a great opportunity to test the effect of extreme habitat change in the variability of dewlap color in the bark anole. Thus, after Irma, Winter and his colleagues immediately returned to each field site to collect reflectance data of the habitats and dewlaps: Irma altered the light profiles across sites and the correlation between dewlap and ambient light disappeared. In order to track how the relationship between dewlap color and habitat lighting develops over time, Winter plans to collect data in 2018: maybe the correlation will be back. Looking forward to seeing the paper.