Rapid introgression of non‐native alleles following hybridization between a native Anolis lizard species and a cryptic invader across an urban landscape

Abstract

Invasive species can impact native populations through competition, predation, habitat alteration, and disease transmission, but also genetically through hybridization.Potential outcomes of hybridization span the continuum from extinction to hybrid speciation and can be further complicated by anthropogenic habitat disturbance.Hybridization between the native green anole lizard (Anolis carolinensis) and a morphologically similar invader (A. porcatus) in south Florida provides an ideal opportunity to study interspecific admixture across a heterogeneous landscape. We used reduced-representation sequencing to describe introgression in this hybrid system and to test for a relationship between urbanization and non-native ancestry. Our findings indicate that hybridization between green anole lineages was probably a limited, historic event, producing a hybrid population characterized by a diverse continuum of ancestry proportions. Genomic cline analyses revealed rapid introgression and disproportionate representation of non-native alleles at many loci and no evidence for reproductive isolation between parental species. Three loci were associated with urban habitat characteristics; urbanization and non-native ancestry were positively correlated, although this relationship did not remain significant when accounting for spatial nonindependence. Ultimately, our study demonstrates the persistence of nonnative genetic material even in the absence of ongoing immigration, indicating that selection favouring non-native alleles can override the demographic limitation of low propagule pressure. We also note that not all outcomes of admixture between native and non-native species should be considered intrinsically negative. Hybridization with ecologically robust invaders can lead to adaptive introgression, which may facilitate the long-term survival of native populations otherwise unable to adapt to anthropogenically mediated global change.

Niche conservatism and spread explain introgression between native and invasive fish

“…Introgression has shown to be a significant threat for native species, including the Candy Darter (Etheostoma osburni Hubbs and Trautman 1932) in Virginia and West Virginia, USA (Gibson et al, 2019), the California Tiger Salamander (Ambystoma californiense Gray 1853) in California, USA (Fitzpatrick et al, 2010), and Green Anolis Lizards (Anolis carolinensis Voigt 1832) in Florida, USA (DeVos et al, 2023).…”

“…Given the threatened status and smaller population sizes of Western Banded Killifish (Hartman et al., 2023), the ongoing process of admixture and potential genetic swamping by Eastern Banded Killifish is a source of concern for this subspecies. Introgression has shown to be a significant threat for native species, including the Candy Darter ( Etheostoma osburni Hubbs and Trautman 1932) in Virginia and West Virginia, USA (Gibson et al., 2019), the California Tiger Salamander ( Ambystoma californiense Gray 1853) in California, USA (Fitzpatrick et al., 2010), and Green Anolis Lizards ( Anolis carolinensis Voigt 1832) in Florida, USA (DeVos et al., 2023). Small populations are more susceptible to the threat of genetic swamping because of limited conspecific mate options (Gibson et al., 2019; Lawson et al., 2017).…”

“…While human‐mediated hybridisation between native and invasive taxa has been widely documented (e.g. DeVos et al., 2023; Fitzpatrick et al., 2010; Gibson et al., 2019), there is limited understanding of the underlying factors that promote successful hybridisation and spatial distribution of hybrid individuals across the landscape.…”

Stronger evidence for genetic ancestry than environmental conditions in shaping the evolution of a complex signalling trait during biological invasion

“…The genotype–environment association (GEA) analyses aimed to determine whether dewlap‐associated SNPs are also associated with environmental variables that are important from the perspective of dewlap signal effectiveness. We followed the approach described by DeVos et al (2023) and used a latent factor mixed model (LFMM), as implemented in the lfmm R package (v. 1.1; Frichot et al, 2013). To correct for the confounding effect of population structure, we set K = 2, which corresponds to the main genetic subdivision in our dataset (see ‘Population structure’ results).…”

When adaptation is slowed down: Genomic analysis of evolutionary stasis in thermal tolerance during biological invasion in a novel climate

“…Also, adaptive alleles that are already segregating in some populations can quickly be transferred via hybridization (e.g. DeVos et al, 2023; Valencia‐Montoya et al, 2020). Lastly, research on invasive species has provided evidence that non‐recombining regions of the genome like chromosomal inversions can drive rapid evolution (e.g.…”