Global patterns of genomic and phenotypic variation in the invasive harlequin ladybird

Abstract

Background The harlequin ladybird Harmonia axyridis (Coleoptera: Coccinellidae), native to Asia, has been introduced to other major continents where it has caused serious negative impacts on local biodiversity. Though notable advances to understand its invasion success have been made during the past decade, especially with then newer molecular tools, the conclusions reached remain to be confirmed with more advanced genomic analyses and especially using more samples from larger geographical regions across the native range. Furthermore, although H. axyridis is one of the best studied invasive insect species with respect to life history traits (often comparing invasive and native populations), the traits responsible for its colonization success in non-native areas warrant more research. Results Our analyses of genome-wide nuclear population structure indicated that an eastern Chinese population could be the source of all non-native populations and revealed several putatively adaptive candidate genomic loci involved in body color variation, visual perception, and hemolymph synthesis. Our estimates of evolutionary history indicate (1) asymmetric migration with varying population sizes across its native and non-native range, (2) a recent admixture between eastern Chinese and American populations in Europe, (3) signatures of a large progressive, historical bottleneck in the common ancestors of both populations and smaller effective sizes of the non-native population, and (4) the southwest origin and subsequent dispersal routes within its native range in China. In addition, we found that while two mitochondrial haplotypes-Hap1 and Hap2 were dominant in the native range, Hap1 was the only dominant haplotype in the non-native range. Our laboratory observations in both China and USA found statistical yet slight differences between Hap1 and Hap2 in some of life history traits. Conclusions Our study on H. axyridis provides new insights into its invasion processes into other major continents from its native Asian range, reconstructs a geographic range evolution across its native region China, and tentatively suggests that its invasiveness may differ between mitochondrial haplotypes.

Population Genomics and Genetic Diversity of the Invasive Chrysanthemum Lace Bug (Corythucha Marmorata) Across Its Invasive Range in Japan

“…If founder populations remain small over many generations, they can lose most of their genetic variation via genetic drift, leading to high levels of inbreeding, a process known as a genetic bottleneck (Nei et al 2011). Alternatively, populations of alien species may show a large fraction of the genetic variability of the native population when introductions involve many individuals (Li et al 2023;Parvizi et al 2023). Similarly, the genetic diversity sampled by an alien introduction will be high if founder populations come from different source populations of the native range through multiple introductions due to intraspeci c admixture (Sakata et al 2015;Ortego et al 2021;Poveda-Martínez et al 2022;Parvizi et al 2023).…”

“…insects, such as Harmonia axyridis, Coenonympha hero, and Nyctelia confuse. It has been proposed that the Last Glacial Maximum triggered a demographic collapse, subsequently followed by a population expansion, as indicated by genetic and demographic signatures(Li et al 2020(Li et al , 2023; Sherpa and Després 2021). Our genetic evidence is consistent with the ndings ofSakata et al (2015), as the cp markers for goldenrod suggest a recent post-glacial population expansion which has contributed to the current genetic structure patterns of the native lace bug populations.…”

Go west: Population genomics reveals unexpected population fluctuations and little gene flow in Western hemisphere populations of the predatory lady beetle, Hippodamia convergens

“…Genetic data are important sources of information for gaining insight into historical and recent evolutionary history of species that have had their populations established or augmented by large-scale releases of individuals, as occurs during biological control (Jones et al, 2023;Kajita et al, 2012;Li et al, 2019Li et al, , 2020Li et al, , 2021Li et al, , 2023Sentis et al, 2022;Sethuraman et al, 2020;Wang et al, 2023).…”

“…While population augmentations can be demographically and economically beneficial, they can also adversely impact intraspecific genetic variation by causing the breakdown of local adaptations, loss of genetic variability, and the reshaping of population structure (Laikre et al., 2010; Simberloff & Stiling, 1996; Terui et al., 2023; Wajnberg et al., 2001). Genetic data are important sources of information for gaining insight into historical and recent evolutionary history of species that have had their populations established or augmented by large‐scale releases of individuals, as occurs during biological control (Jones et al., 2023; Kajita et al., 2012; Li et al., 2019, 2020, 2021, 2023; Sentis et al., 2022; Sethuraman et al., 2020; Wang et al., 2023). Population genomics, in particular, provides a powerful approach toward understanding how genetic variation has been impacted on a recent time scale (Maigret et al., 2020; Nunziata et al., 2017), including the time frame encompassing human‐mediated movements and augmentations of populations during biological control.…”