Testing for adaptive changes linked to range expansion following a single introduction of the fall webworm

Abstract

Adaptive evolution following colonization can affect the impact of invasive species. The fall webworm (FWW) invaded China 40 years ago through a single introduction event involving a severe bottleneck and subsequently diverged into two genetic groups. The well‐recorded invasion history of FWW, coupled with a clear pattern of genetic divergence, provides an opportunity to investigate whether there is any sign of adaptive evolution following the invasion. Based on genome‐wide SNPs, we identified genetically separated western and eastern groups of FWW and correlated spatial variation in SNPs with geographical and climatic factors. Geographical factors explained a similar proportion of the genetic variation across all populations compared with climatic factors. However, when the two population groups were analysed separately, environmental factors explained more variation than geographical factors. SNP outliers in populations of the western group had relatively stronger response to precipitation than temperature‐related variables. Functional annotation of SNP outliers identified genes associated with insect cuticle protein potentially related to desiccation adaptation in the western group and genes associated with lipase biosynthesis potentially related to temperature adaptation in the eastern group. Our study suggests that invasive species may maintain the evolutionary potential to adapt to heterogeneous environments despite a single invasion event. The molecular data suggest that quantitative trait comparisons across environments would be worthwhile.

Rapid evolutionary adaptation: Potential and constraints

“…Another study deals with the rapid adaptation of the FWW, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), native to North‐America and invasive in mainland China (Dai et al., 2023). The invasion through a single introduction event 40 years ago likely involved a severe bottleneck and the subsequent divergence into two genetic groups.…”

“…Dai et al. (2023) investigate whether there is any footprint of adaptive evolution following this recent invasion. Using ddRADseq sequencing for 265 individuals (covering approximately 4% of the genome and yielding 59,261 SNPs), they identify genetically separated western and eastern groups of FWW, albeit the genetic diversity and differentiation are very small due to the very strong invasion bottleneck event.…”

“…Using redundancy analysis, Liu et al then identify candidate functional genes, putatively exhibiting footprints of selection, suggesting that bioclimatic variables, especially sea surface temperature, may generate spatially varying selection for S. tenuifilis. In general, however, this study is still rather preliminary in disentangling neutral and selective forces and testing for the occurrence of strong selection and its role in rapid adaptation.Another study deals with the rapid adaptation of the FWW, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), native to North-America and invasive in mainland China(Dai et al, 2023). The invasion through a single introduction event 40 years ago likely involved a severe bottleneck and the subsequent divergence into two genetic groups Dai et al (2023).…”

“…In general, however, this study is still rather preliminary in disentangling neutral and selective forces and testing for the occurrence of strong selection and its role in rapid adaptation.Another study deals with the rapid adaptation of the FWW, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), native to North-America and invasive in mainland China(Dai et al, 2023). The invasion through a single introduction event 40 years ago likely involved a severe bottleneck and the subsequent divergence into two genetic groups Dai et al (2023). investigate whether there is any footprint of adaptive evolution following this recent invasion.…”

“…reproduction with large variance in offspring production) common to many fish, invertebrates and fungi, can on one hand hasten the fixation of beneficial alleles but on the other hand make it less likely to occur (Eldon & Stephan, 2023; Korfmann et al., 2023). Two examples of adaptation (invasion) to new habitats by strong positive selection are then presented in population genomics studies of the fall webworm (FWW; Dai et al., 2023) and the common hairfin anchovy ( Setipinna tenuifilis ) (Liu et al., 2023). Finally, a review summarises findings from genomic studies on the role of transposable elements (TEs) in determining the evolutionary potential of crop pathogens.…”