The spatial ecology of Mojave Rattlesnakes (Crotalus scutulatus), Prairie Rattlesnakes (C. viridis), and their hybrids in southwestern New Mexico
Data files
Mar 07, 2024 version files 32.82 MB
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Delta_seasonal_movements.csv
2.21 KB
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README.md
8.27 KB
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Scut.Vir.Hybrid.RADseq.WGS.205.QC.missing.corrected.filtered.snps.g.vcf.gz
32.80 MB
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yearly_movements.csv
4.55 KB
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yearly_UDs.csv
7.93 KB
Abstract
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.
README: 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
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.