Data from: Urban hubs of connectivity: contrasting patterns of gene flow within and among cities in the Western black widow spider

As urbanization drastically alters the natural landscape and generates
novel habitats within cities, the potential for changes to gene flow for
urban-dwelling species increases. The Western black widow spider
(Latrodectus hesperus) is a medically-relevant urban adapter pest species,
for which we have previously identified population genetic signatures
consistent with urbanization facilitating gene flow, likely due to
human-mediated transport. Here, in an analysis of 1.9 million genomewide
SNPs, we contrast broad-scale geographic analyses of 10 urban and 11
non-urban locales with fine-scale within-city analyses including 30 urban
locales across the Western U.S. These hierarchical datasets enable us to
test hypotheses of how urbanization impacts multiple urban cities and
their genetic connectivity at different spatial scales. Coupled fine-scale
and broad-scale analyses reveal contrasting patterns of high and low
genetic differentiation among locales within cities as a result of low and
high genetic connectivity, respectively, of these cities to the overall
population network. We discuss these results as they challenge the use of
cities as replicates of urban eco-evolution, and have implications for
conservation and human health in a rapidly growing urban habitat.