DOI: 10.5061/dryad.tht76hf59
title: The spatial ecology of Mojave Rattlesnakes (Crotalus scutulatus), Prairie Rattlesnakes (C. viridis), and their hybrids in southwestern New Mexico

description: Hybridization between species provides unique opportunities to understand
 evolutionary processes that are linked to reproductive isolation and,
 ultimately, speciation. However, the extrinsic factors that limit
 hybridization are poorly understood for most animal systems. Although the
 spatial ecology of individuals in natural habitats is fundamental to
 shaping reproductive success and survival, analyses of the spatial ecology
 of hybrids and their parental groups are rarely reported. Here, we used
 radiotelemetry to monitor wild rattlesnakes across an interspecific hybrid
 zone (Crotalus scutulatus and Crotalus viridis) and measured movement
 parameters and space use (utilization distributions) of individuals to
 evaluate the hypothesis that hybridization resulted in transgressive or
 atypical movement patterns. Unexpectedly, of the spatial metrics we
 investigated, we found that hybrids were very similar to parental
 individuals. Nonetheless, hybrids did show increased patchiness of core
 utilization distributions, but this result is likely to be driven by
 increased habitat patchiness in the hybrid zone. Overall, we did not find
 evidence for overt extrinsic barriers to hybridization associated with
 spatial ecology; thus, we suggest that the close evolutionary history
 between the two parental species and their ecological and behavioural
 similarities are likely to increases the probability of hybridization
 events in this unique region of New Mexico.
description: # Hybrids in space: the spatial ecology of Mojave Rattlesnakes (*Crotalus
 scutulatus*), Prairie Rattlesnakes (*C. viridis*), and their hybrids in
 southwestern New Mexico, USA
 [https://doi.org/10.5061/dryad.tht76hf59](https://doi.org/10.5061/dryad.tht76hf59) This dataset includes the final VCF alignment file used for hybrid index analysis, the average distance moved per day, average number of movements per day, utilization distribution sizes and patchiness, and the change in average distance moved per day and average number of movements per day from the dry to wet season for each individual snake. These data were used in order to quantify the spatial ecology of snakes dispersed across a hybrid zone between Mojave (*Crotalus scutulatus*) and Prairie (*C. viridis*) Rattlesnakes. The VCF alignment data were collected via raw sequence reads from DNA extractions from blood stored in lysis buffer. Movement metrics were calculated from GPS points collected via field radiotelemetry. Hybrids were shown to have a greater number of core UD patches than parental individuals. However, in all other regards, hybrids and parentals were generally similar to each other in their spatial ecology. ## Description of the data and file structure **VCF alignment:** This file contains the biallelic variants for all individuals used in the behavioral analyses. **For all data:** NA, N/A, or na = data was not collected due to the data being not applicable (ex., NA for Reproductive_status for male snakes since they can not become pregnant, NA for n since the utilization distribution area is a average between the two years utilization distributions). **yearly_movements:** * Distance_moved_per_day_m = total distance the snake moved during tracking period divided by the number of days of the tracking period * SE_dmd_m = Standard Error using the distances between each successive location the snake was tracked to and the number of days between the first and last locations as the sample size. * Number_of_days_per_movement = the number of times two successive locations was greater than zero meters apart (aka the number of movements performed by the snake) divided by the number of days of the tracking period * n = the number of GPS locations used to calculate the movement metrics * species = the putative grouping that the snake was assigned to based on site of capture and morphology * CRSC = *Crotalus scutulatus* * SCVI = Hybrid * CRVI = *Crotalus viridis* * sex = sex of the snake * f = female * m = male * Reproductive_status = if the snake was a female, was it pregnant or not * na = male snake * np = non-pregnant female * mass_g = mass of the snake to the nearest gram * SVL_mm = Snout-Vent Length of the snake to the nearest millimeter * ID = the ID of the individual * year = the year/s that GPS points from the snake was used in the calculation of the movement metrics * HI_scutulatus_proportion = 1-HI_viridis_proportion * HI_viridis_proportion = Hybrid index based on the VCF alignment * genetic_species = which lineage the individual belonged to based on its hybrid index and the 0.05 and 0.95 cutoffs for parental groupings. * CRSC = *Crotalus scutulatus* * SCVI = Hybrid * CRVI = *Crotalus viridis* **yearly_UDs:** * MCP100 (ha) = size, in hectares, of the space that the individual used based on a 100% Minimum Convex Polygon * MCP75 (ha) = size, in hectares, of the space that the individual used based on a 75% Minimum Convex Polygon * MCP50 (ha) = size, in hectares, of the space that the individual used based on a 50% Minimum Convex Polygon * KDE95ref (ha) = size, in hectares, of the utilization distribution used by an individual used based on a 95% fixed Kernel Density Estimator using the h-reference smoothing method * KDE75ref (ha) = size, in hectares, of the utilization distribution used by an individual used based on a 75% fixed Kernel Density Estimator using the h-reference smoothing method * KDE50ref (ha) = size, in hectares, of the utilization distribution used by an individual used based on a 50% fixed Kernel Density Estimator using the h-reference smoothing method * KDE95adHoc (ha) = size, in hectares, of the utilization distribution used by an individual used based on a 95% fixed Kernel Density Estimator using the ad-hoc smoothing method described in Kie 2013 * KDE75adHoc (ha) = size, in hectares, of the utilization distribution used by an individual used based on a 75% fixed Kernel Density Estimator using the ad-hoc smoothing method described in Kie 2013 * KDE50adHoc (ha) = size, in hectares, of the utilization distribution used by an individual used based on a 50% fixed Kernel Density Estimator using the ad-hoc smoothing method described in Kie 2013 * bbKDE95 (ha) = size, in hectares, of the utilization distribution used by an individual used based on a 95% autocorrelated Kernel Density Estimator using the brownian bridge movement model * bbKDE75 (ha) = size, in hectares, of the utilization distribution used by an individual used based on a 75% autocorrelated Kernel Density Estimator using the brownian bridge movement model * bbKDE50 (ha) = size, in hectares, of the utilization distribution used by an individual used based on a 50% autocorrelated Kernel Density Estimator using the brownian bridge movement model * n = the number of GPS locations used to calculate the utilization distributions when years were not averaged together * species = the putative grouping that the snake was assigned to based on site of capture and morphology * CRSC = *Crotalus scutulatus* * SCVI = Hybrid * CRVI = *Crotalus viridis* * sex = sex of the snake * f = female * m = male * Reproductive_status = if the snake was a female, was it pregnant or not * N/A = male snake * np = non-pregnant female * SVL_mm = Snout-Vent Length of the snake to the nearest millimeter * mass_g = mass of the snake to the nearest gram * ID = the ID of the individual * year = the year/s that GPS points from the snake was used in the calculation of the movement metrics * number of bbKDE50 patches = the number of discontinuous patches estimated by way of 50% brownian bridge Kernel Density Estimator * HI_scutulatus_proportion = 1-HI_viridis_proportion * HI_viridis_proportion = Hybrid index based on the VCF alignment * genetic_species = which lineage the individual belonged to based on its hybrid index and the 0.05 and 0.95 cutoffs for parental groupings. * CRSC = *Crotalus scutulatus* * SCVI = Hybrid * CRVI = *Crotalus viridis* **Delta_seasonal_movements:** * species = the putative grouping that the snake was assigned to based on site of capture and morphology * CRSC = *Crotalus scutulatus* * SCVI = Hybrid * CRVI = *Crotalus viridis* * sex = sex of the snake * f = female * m = male * Reproductive_status = if the snake was a female, was it pregnant or not * N/A = male snake * np = non-pregnant female * mass_g = mass of the snake to the nearest gram * SVL_mm = Snout-Vent Length of the snake to the nearest millimeter * ID = the ID of the individual * year = the year/s that GPS points from the snake was used in the calculation of the movement metrics * delta_dmd = the difference between the average distance moved per day, in meters, between the wet and dry seasons for each individual snake * delta_fm = the difference between the average number of days between moves, in meters, between the wet and dry seasons for each individual snake * HI_scutulatus_proportion = 1-HI_viridis_proportion * HI_viridis_proportion = Hybrid index based on the VCF alignment * genetic_species = which lineage the individual belonged to based on its hybrid index and the 0.05 and 0.95 cutoffs for parental groupings. * CRSC = *Crotalus scutulatus* * SCVI = Hybrid * CRVI = *Crotalus viridis* ## Sharing/Access information For inquires about the data, feel free to contact the corresponding author of the paper, Dr. Dylan Maag. ## Code/Software The VCF alignment data file can be accessed by software such as vcftools or bcftools.