Evolution 2019: Population Structure of an Island Anole After Volcanic Eruption on Montserrat

In the 1990s, volcanic eruptions occurred on the island of Montserrat, which of course led to a reduction in the resident population of the plymouth anole, Anolis lividus, in the area of the island affected by the blast. However, populations appear to have recovered. But how? Were there a limited number of individuals that survived the volcano, and have now succesfully repopulated? Or did individuals from the northern region of the island colonize the southern region after the eruption? In addition, different populations throughout the region exhibit different body coloration, ranging from dark green to light brown. Does this morphological diversity represent underlying genetic divergence?

Catherine Jung is addressing these questions using genetic data from historical (1991-1992) and current (2018) samples. She has sequenced one nuclear and two mitochondrial genes to determine the relatedness among current populations across the island. Interestingly, she’s found no signatures of genetic structure across the island so far. She plans to continue this work by incorporating the genetic data from the historical specimens and performing more formalized demographic models to determine whether current southern populations (which were re-populated after the volcano) are more related to current northern populations (unaffected by the volcano), or historic southern populations (pre-volcano). As of right now, the question remains open, but stay tuned for more data! Answering these types of questions about the dynamics of population recovery is an important part of conservation research and application, and Jung’s work will contribute to our understanding of these processes in anoles.