High‐throughput sequencing of transposable element insertions suggests adaptive evolution of the invasive Asian tiger mosquito towards temperate environments

Abstract

Invasive species represent unique opportunities to evaluate the role of local adaptation during colonization of new environments. Among these species, the Asian tiger mosquito, Aedes albopictus, is a threatening vector of several human viral diseases, including dengue and chikungunya, and raises concerns about the Zika fever. Its broad presence in both temperate and tropical environments has been considered the reflection of great "ecological plasticity." However, no study has been conducted to assess the role of adaptive evolution in the ecological success of Ae. albopictus at the molecular level. In the present study, we performed a genomic scan to search for potential signatures of selection leading to local adaptation in one-hundred-forty field-collected mosquitoes from native populations of Vietnam and temperate invasive populations of Europe. High-throughput genotyping of transposable element insertions led to the discovery of more than 120,000 polymorphic loci, which, in their great majority, revealed a virtual absence of structure between the biogeographic areas. Nevertheless, 92 outlier loci showed a high level of differentiation between temperate and tropical populations. The majority of these loci segregate at high insertion frequencies among European populations, indicating that this pattern could have been caused by recent adaptive evolution events in temperate areas. An analysis of the overlapping and neighbouring genes highlighted several candidates, including diapause, lipid and juvenile hormone pathways.

Cold adaptation in the Asian tiger mosquito's native range precedes its invasion success in temperate regions

“…Although invaders originating from cold environments were probably preadapted for invading temperate regions, some studies suggest the two other adaptation scenarios (genetic shift and bridgehead scenario) might still occur. The only other study investigating genomic signatures of selection in A. albopictus compared temperate invasive and tropical native populations (Goubert et al 2017). None of the potentially adaptive genes detected by the later study match those we detected within the native range, possibly because different genomic regions were targeted in the two studies (transposable elements insertion polymorphisms and ddRADseq SNPs).…”

“…The only other study investigating genomic signatures of selection in A. albopictus compared temperate invasive and tropical native populations (Goubert et al. ). None of the potentially adaptive genes detected by the later study match those we detected within the native range, possibly because different genomic regions were targeted in the two studies (transposable elements insertion polymorphisms and ddRADseq SNPs).…”

“…Concordantly, transcriptomic studies have shown that a few thousand genes, involved in the perception of external factors and several metabolic pathways, were differentially expressed between diapausing and nondiapausing conditions in A. albopictus (Poelchau et al 2013a, b;Huang et al 2015). A recent study based on transposable element insertions also reported genomic signatures of selection between temperate invasive (Europe) and tropical native (Vietnam) populations (Goubert et al 2017). However, this later study does not indicate whether adaptations arose in invasive populations (genetic shift) and/or in the native population from which invasive ones were introduced (preadaptation).…”

“…A recent study based on transposable element insertions also reported genomic signatures of selection between temperate invasive (Europe) and tropical native (Vietnam) populations (Goubert et al. ). However, this later study does not indicate whether adaptations arose in invasive populations (genetic shift) and/or in the native population from which invasive ones were introduced (preadaptation).…”

Rapid and strong population genetic differentiation and genomic signatures of climatic adaptation in an invasive mealybug

“…Invertebrate species are particularly strongly influenced by climatic conditions on many biological characters, such as reproduction, developmental durations, diapause and survival. Studies have shown differences in climatic adaptation between invasive and non‐invasive populations of invertebrates (Goubert et al, 2017; Hill, 2013; Jarošík, Kenis, Honěk, Skuhrovec, & Pyšek, 2015; Urbanski et al, 2012) and comparisons of species distributions in native and invaded regions provide additional indirect support for adaptive evolutionary shifts (Hoffmann, 2017). In newly colonized areas, climatic differences between early invaded areas and distribution edges may lead to differed selective pressures, and the opportunity to investigate rates of climatic adaptation in invading invertebrates.…”