Knowledge of genetic structure, geographic distance and environmental heterogeneity can be used to identify environmental features and natural history traits that influence dispersal and gene flow. Foraging mode is a trait that might predict dispersal capacity in snakes, because actively foragers typically have greater movement rates than ambush predators. Here we test the hypothesis that two actively foraging snakes have higher levels of gene flow than two ambush predators. We evaluated these four co-distributed species of snakes in the Brazilian Amazon. Snakes were sampled along an 880km transect from the central to the southwest of the Amazon basin, which covered a mosaic of vegetation types and seasonal differences in climate. We analyzed thousands of Single Nucleotide Polymorphisms (SNPs) to compare patterns of neutral gene flow based on isolation by geographic distance (IBD) and environmental resistance (IBR). We show that IBD and IBR were only evident in ambush predators, implying lower levels of dispersal than the active foragers. Therefore, gene flow was high enough in the active foragers analyzed here to prevent any build-up of spatial genotypic structure with respect to geographic distance and environmental heterogeneity.
Geographic coordinates of Bothrops atrox sampled in the Amazon rainforests
Geographic coordinates were obtained by field work, in sampling sites distributed along the Brazilian Amazon rainforests, from Manaus (central Amazon basin) to Porto Velho (southwestern Amazon basin).
lancehead_coordinates.txt
Geographic coordinates of Corallus hortulanus sampled in the Amazon rainforests
Geographic coordinates were obtained by field work, in sampling sites distributed along the Brazilian Amazon rainforests, from Manaus (central Amazon basin) to Porto Velho (southwestern Amazon basin).
treeboa_coordinates.txt
Geographic coordinates of Leptodeira annulata annulata sampled in the Amazon rainforests
Geographic coordinates were obtained by field work, in sampling sites distributed along the Brazilian Amazon rainforests, from Manaus (central Amazon basin) to Porto Velho (southwestern Amazon basin).
cateyed_coordinates.txt
Geographic coordinates of Philodryas georgeboulengeri sampled in the Amazon rainforests
Geographic coordinates were obtained by field work, in sampling sites distributed along the Brazilian Amazon rainforests, from Manaus (central Amazon basin) to Porto Velho (southwestern Amazon basin).
sharpnose_coordinates.txt
Pairwise genetic distance matrix of Bothrops atrox
Genetic distance was estimated among individuals, based on the Ritland relatedness index.
lancehead_genetic_distance.txt
Pairwise genetic distance matrix of Corallus hortulanus
Genetic distance was estimated among individuals, based on the Ritland relatedness index.
treeboa_genetic_distance.txt
Pairwise genetic distance matrix of Leptodeira annulata annulata
Genetic distance was estimated among individuals, based on the Ritland relatedness index.
cateyed_genetic_distance.txt
Pairwise genetic distance matrix of Philodryas georgeboulengeri
Genetic distance was estimated among individuals, based on the Ritland relatedness index.
sharpnose_genetic_distance.txt
Geographic distance among samples of Bothrops atrox
Log-geographic distance was calculated using Euclidean distances based on geographic coordinates.
lancehead_log_geographic_distance.txt
Geographic distance among samples of Corallus hortulanus
Log-geographic distance was calculated using Euclidean distances based on geographic coordinates.
treeboa_log_geographic_distance.txt
Geographic distance among samples of Leptodeira annulata annulata
Log-geographic distance was calculated using Euclidean distances based on geographic coordinates.
cateyed_log_geographic_distance.txt
Geographic distance among samples of Philodryas georgeboulengeri
Log-geographic distance was calculated using Euclidean distances based on geographic coordinates.
sharpnose_log_geographic_distance.txt
R script for testing snakes gene flow based on IBD and IBR
R script to test for the effects of isolation-by-distance and isolation-by-resistance on gene flow of snakes from the Amazon rainforests.
Script_Fraga et al.doc
Raster surface - rainfall seasonality in the Amazon
Raster surface used to optimize resistance surfaces in order to test for the effects of isolation-by-resistance on gene flow of snakes from the Amazon rainforests.
rain.asc
Raster surface - temperature seasonality in the Amazon
Raster surface used to optimize resistance surfaces in order to test for the effects of isolation-by-resistance on gene flow of snakes from the Amazon rainforests.
temperature.asc
Raster surface - vegetation cover type in the Amazon
Raster surface used to optimize resistance surfaces in order to test for the effects of isolation-by-resistance on gene flow of snakes from the Amazon rainforests.
vegetation.asc