The role of the environment on the genetic divergence between two Boa imperator lineages

Abstract

Aim A fundamental problem in evolutionary biology has been understanding the role of environmental factors in the process of genetic diversification. Our main goal was to define the ecological niches of two Boa imperator lineages, in order to assess if environmental drivers could be associated with the divergence and genetic variation between them. We quantified the environmental niches at two evolutionary and geographical scales: regional‐historical (lineages) and local‐ecological (individuals within lineages). Location Neotropical region of Mexico and mainland Central America. Methods We performed ecological niche modelling (ENM) methods by defining the accessibility area per B. imperator lineage, based on their geographic ranges, to analyse ecological and geographical distributions. We applied statistics of niche overlap, interpredictability, equivalency and similarity. We tested the niche‐centrality hypothesis within lineages by evaluating the relationship between genetic metrics and the distance to ecological and geographical centroids. Results Temperature seasonality, precipitation and elevation were the most informative environmental variables (GARP and MaxEnt). Ecological interprediction and niche similarity and equivalency tests revealed a dynamic process of niche evolution, where the niches of the two lineages are not identical but still showed a signature of niche conservatism. Correlation analyses between genetic variability and structure showed negative correlations with distance to ecological and geographical centroids at the local level. Main conclusions Our results support the role of environmental variables as significant and highly accurate predictors of lineage distribution and divergence, in agreement with the boa's evolutionary history. The niches of the two lineages are not identical, sharing environmental niche space but not all ecological variables. A historically more recent signal of genetic structure within lineages was evident, where the quality of the ecological niche further influences genetic distribution patterns within populations. Our results illustrate how ENM may validate evolutionary patterns from a biogeographical and phylogeographical framework.

Potential distribution and habitat connectivity of Crotalus triseriatus in Central Mexico

“…We applied the Maximum Entropy algorithm using MAXENT software (Phillips et al 2006). We ran the model in MAXENT with 10 bootstraps replicates with 75-25% for training and testing, respectively (Anderson et al 2003;Chefaoui et al 2005;Suárez-Atilano et al 2017). We only used linear and quadratic features due to low sample size (Merow et al 2013).…”

A tale of four bears: Environmental signal on the phylogeographical patterns within the extant Ursus species

“…Understanding how the environment can shape the diversification patterns and geographical distribution of species represents an essential question in evolutionary biology (Kalkvik, Stout, Doonan, & Parkinson, 2012;Rolland et al, 2018;Wooten & Gibbs, 2012). The combined use of ecological niche modelling (ENM) and phylogeographical methods has allowed researchers to evaluate the effect of environmental factors on the distribution of genetic variation throughout geographical ranges, as well as the role those factors play in species divergence (Alvarado-Serrano & Knowles, 2014;Collevatti, Terribile, Diniz-Filho, & Lima-Ribeiro, 2015;Richards, Carstens, & Knowles, 2007;Suárez-Atilano, Rojas-Soto, Parra, & Vázquez-Domínguez, 2017). In this context, hypotheses about ecological niche conservatism and niche diversification have been evaluated in different taxa (Suárez-Atilano et al, 2017;Yannic et al, 2017), where the former is defined as the evolutionary pattern of shared ecological characteristics by species or lineages with their ancestors (Wiens & Graham, 2005), namely when two or more closely related species are more ecologically similar than expected by their genetic relationships, retaining ancestral ecological characters (Losos, 2008).…”

Boas of the World (Superfamily Booidae): A Checklist With Systematic, Taxonomic, and Conservation Assessments

“…Originally described as Constrictor constrictor sigma (mistakenly attributed to M. A. by McDiarmid et al [1999]); Zweifel (1960) relegated it to the synonymy of Boa constrictor imperator. Card et al (2016) recommended elevation to species level based largely on molecular data, while Suárez-Atilano et al (2017) suggest that the species is further defined ecologically and geographically. No subspecies are recognized.…”

“…Distribution. The Pacific coast of Mexico west of the Isthmus of Tehuantepec (including three islands in the Tres Marías (Nayarit): María Madre, María Magdalena, and María Cleofas (Zweifel, 1960;Card et al, 2016;Suárez-Atilano et al, 2017).…”