Biology subjects

Munshi-South, J.

Publications and source records attributed to Munshi-South, J..

6 recordsLinked to original sources

bioRxiv2025

Cities as evolutionary incubators for the global spread of the Spotted Lanternfly

Habitat destruction and invasive species pose two of the greatest global threats to biodiversity. These factors do not operate in isolation, and nowhere is their interaction more apparent than in urban environments. Urban organisms rapidly evolve under novel ecological circumstances where they also encounter anthropogenic opportunities for range expansion. Here, we examine the role of urbanization in the invasive success of an emerging global pest, the Spotted Lanternfly, during colonization and expansion. We demonstrate that the invasive population in the United States has undergone three sequential bottlenecks, resulting in significantly reduced genetic diversity and elevated inbreeding. The success of this invasive population may be in part attributable to adaptation in the native range prior to the invasion: we detect divergence between urban and rural lanternflies in Shanghai, China, (the invasion origin) in genes related to stress response, metabolism, and detoxification pathways. Additionally, we detect genomic signatures of selection in the invasive population suggesting adaptive refinement as the invasion progresses. This study provides evidence of adaptive evolution in response to urbanization despite substantial loss of genetic diversity, and implicates adaptive responses to pesticide application, dietary shifts, and climate in the invasive success of the Spotted Lanternfly.

evolutionary biology↗

bioRxiv2025

Subways, zoning and social factors influence the dispersal and genetic connectivity of an iconic urban pest, the brown rat (Rattus norvegicus) across a complex cityscape

Cities present unique ecological challenges and opportunities for species that have adapted to human-dominated environments. To understand how urban landscape heterogeneity shapes the movements of an iconic urban animal, the brown rat (Rattus norvegicus), we investigated the factors influencing rat genetic connectivity across Manhattan, New York City. We generated genome-wide SNP data from rats sampled throughout Manhattan as well as paired surface-subway locations, created a habitat suitability model using systematic municipal rat survey data, and employed landscape genetic approaches to identify urban features influencing rat gene flow. Our models revealed that underground subway tunnels were the strongest facilitator of rat gene flow, with municipal zoning also strongly influencing connectivity, particularly through low / medium-density residential areas. Habitat suitability analysis showed that high human population density, old building ages, and lower median household income were the strongest predictors of rat presence. Subterranean sampling revealed that rats in subway stations exhibited greater genetic relatedness than surface rats at short distances but lower inbreeding coefficients, suggesting underground tunnels facilitate longer-distance dispersal while maintaining some connectivity to surface populations. These findings demonstrate that physical infrastructure, political, and socioeconomic factors shape urban rat ecology, with implications for more targeted approaches to pest management in complex urban environments. This study is the first comprehensive analysis of rat dispersal and genetic connectivity in relation to complex cityscape heterogeneity.

evolutionary biology↗

bioRxiv2023

Does urbanization lead to parallel demographic shifts across the world in a cosmopolitan plant?

Urbanization is occurring globally, leading to dramatic environmental changes that are altering the ecology and evolution of species. In particular, the expansion of human infrastructure and the loss and fragmentation of natural habitats in cities is predicted to increase genetic drift and reduce gene flow by reducing the size and connectivity of populations. Alternatively, the "urban facilitation model" suggests that some species will have greater gene flow into and within cities leading to higher diversity and lower differentiation in urban populations. These alternative hypotheses have not been contrasted across multiple cities. Here, we used the genomic data from the Global Urban Evolution project (GLUE), to study the effects of urbanization on non-adaptive evolutionary processes of white clover (Trifolium repens) at a global scale. We found that white clover populations presented high genetic diversity and no evidence of a reduction in Ne linked to urbanization. On the contrary, we found that urban populations were less likely to experience a recent decrease in effective population size than rural ones. In addition, we found little genetic structure among populations both globally and between urban and rural populations, which showed extensive gene flow between habitats. Interestingly, white clover displayed overall higher gene flow within urban areas than within rural habitats. Our study provides one of the largest comprehensive tests of demographic effects of urbanization and our results contrast the common perception that heavily altered and fragmented urban environments will reduce the effective population size and genetic diversity of populations and contribute to their isolation.

evolutionary biology↗

bioRxiv2021

Determinants of genetic diversity and species richness of North American amphibians

Ecological limits on the population sizes and number of species a region is capable of supporting are thought to simultaneously produce spatial patterns in genetic diversity and species richness. However, we do not know the extent to which resource-based environmental limits jointly determine these patterns of biodiversity in ectotherms because of their low energy requirements compared to endotherms. Here, we adapt a framework for the ways ecological limits may shape genetic diversity and species richness previously tested in mammals for amphibians to determine whether similar processes produce continental patterns of biodiversity across both taxa. Repurposing open, raw microsatellite data from 19 species sampled at 554 sites in North America we found that spatial patterns of genetic diversity run opposite to patterns of species richness and genetic differentiation. However, while measures of resource availability and niche heterogeneity predict 89% of the variation in species richness, these landscape metrics are poor predictors of genetic diversity. Although heterogeneity appears to be an important driver of genetic and species biodiversity patterns in both amphibians and mammals, our results suggest that variation in genetic diversity both within and across species makes it difficult to infer general processes producing spatial patterns of amphibian genetic diversity.

evolutionary biology↗

bioRxiv2020

Genetic Adaptation in New York City Rats

Brown rats (Rattus norvegicus) thrive in urban environments by navigating the anthropocentric environment and taking advantage of human resources and by-products. From the human perspective, rats are a chronic problem that causes billions of dollars in damage to agriculture, health and infrastructure. Did genetic adaptation play a role in the spread of rats in cities? To approach this question, we collected whole-genome sequences from 29 brown rats from New York City (NYC) and scanned for genetic signatures of adaptation. We tested for (i) high-frequency, extended haplotypes that could indicate selective sweeps and (ii) loci of extreme genetic differentiation between the NYC sample and a sample from the presumed ancestral range of brown rats in northeast China. We found candidate selective sweeps near or inside genes associated with metabolism, diet, the nervous system and locomotory behavior. Patterns of differentiation between NYC and Chinese rats at putative sweep loci suggests that many sweeps began after the split from the ancestral population. Together, our results suggest several hypotheses on adaptation in rats living in close proximity to humans.

evolutionary biology↗

bioRxiv2018

Brown rat demography reveals pre-commensal structure in eastern Asia prior to expansion into Southeast Asia during the Song dynasty

Fossil evidence indicates that the globally-distributed brown rat (Rattus norvegicus) originated in northern China and Mongolia. Historical records report the human-mediated invasion of rats into Europe in the 1500s, followed by global spread due to European imperialist activity during the1600s-1800s. We analyzed 14 genomes representing seven previously identified evolutionary clusters and tested alternative demographic models to infer patterns of range expansion, divergence times, and changes in effective population (Ne) size for this globally important pest species. We observed three range expansions from the ancestral population that produced the Pacific (~4.8kya), eastern China (diverged ~0.55kya), and Southeast (SE) Asia (~0.53kya) lineages. Our model shows a rapid range expansion from SE Asia into the Middle East then continued expansion into central Europe 537 years ago (1478 AD). We observed declining Ne within all brown rat lineages from 150-1kya, reflecting population contractions during glacial cycles. Ne increased since 1kya in Asian and European, but not Pacific, evolutionary clusters. Our results support the hypothesis that northern Asia was the ancestral range for brown rats. We suggest that southward human migration across China between 800-1550s AD resulted in the introduction of rats to SE Asia, from which they rapidly expanded via existing maritime trade routes. Finally, we discovered that North America was colonized separately on both the Atlantic and Pacific seaboards, yet by evolutionary clusters of vastly different ages and genomic diversity levels. Our results should stimulate discussions among historians and zooarcheologists regarding the relationship between humans and rats.

evolutionary biology↗