Climate underpins the geographic distribution of Lizard colouration

New paper just out in the American Naturalist. This paper, the first from Mara’s PhD, explores why Wall Lizards vary so much in their colouration. To test this, Mara combined our extensive sampling of colouration from 114 wall lizard populations spread across Italy with fine scale climatic data and the latest spatial analyses. Mara shows that colour ornamentation closely tracks climatic regimes, both within the lineage that the ornamentation originated as well as during its introgression into neighboring Wall Lizard lineages. Specifically, lizards from locations that are hot and dry are more likely to express the green-black colouration compared to populations that are cool and wet. Crucially, these environments allow for prolonged reproductive season and high and reliable opportunities for lizard activity, conditions that should be consistent with heightened sexual selection. Combined these results contribute significantly to our understanding of the extraordinary colour variation in Wall Lizards across the Italian landscape, something that has puzzled naturalists for well over a century. Great work Mara!

Minano, M.R., While, G.M., Yang, W., Burridge, C. P., Sacchi, R., Zuffi, M., Scali, S., Salvi, D. and Uller, T. (2021) Climate shapes the geographic distribution and introgressive spread of color ornamentation in Common Wall Lizards. American Naturalist.

Climate variation across central Italy and the corresponding distribution of the green-black colouration.