RESUMO
Invasive species are increasingly threatening ecosystems and agriculture by rapidly expanding their range and adapting to environmental and human-imposed selective pressures. The genomic mechanisms that underlie such rapid changes remain unclear, especially for agriculturally important pests. Here, we used genome-wide polymorphisms derived from native, invasive, and intercepted samples and populations of the brown marmorated stink bug (BMSB), Halyomorpha halys, to gain insights into population genomics processes that have promoted the successful global invasion of this polyphagous pest. Our analysis demonstrated that BMSB exhibits spatial structure but admixture rates are high among introduced populations, resulting in similar levels of genomic diversity across native and introduced populations. These spatial genomic patterns suggest a complex invasion scenario, potentially with multiple bridgehead events, posing a challenge for accurately assigning BMSB incursions to their source using reduced-representation genomic data. By associating allele frequencies with the invasion status of BMSB populations, we found significantly differentiated single nucleotide polymorphisms (SNPs) located in close proximity to genes for insecticide resistance and olfaction. Comparing variations in allele frequencies among populations for outlier SNPs suggests that BMSB invasion success has probably evolved from standing genetic variation. In addition to being a major nuisance of households, BMSB has caused significant economic losses to agriculture in recent years and continues to expand its range. Despite no record of BMSB insecticide resistance to date, our results show high capacity for potential evolution of such traits, highlighting the need for future sustainable and targeted management strategies.
Assuntos
Ecossistema , Genética Populacional , Heterópteros , Animais , Agricultura , Heterópteros/genética , Resistência a InseticidasRESUMO
BACKGROUND: Brown marmorated stink bug (BMSB), Halyomorpha halys (Hemiptera: Pentatomidae) is native to East Asia but has invaded many countries in the world. BMSB is a polyphagous insect pest and causes significant economic losses to agriculture worldwide. Knowledge on the genetic diversity among BMSB populations is scarce but is essential to understand the patterns of colonization and invasion history of local populations. Efforts have been made to assess the genetic diversity of BMSB using partial mitochondrial DNA sequences but genetic divergence on mitochondria is not high enough to precisely accurately identify and distinguish various BMSB populations. Therefore, in this study, we applied a ddRAD (double digest restriction-site associated DNA) sequencing approach to ascertain the genetic diversity of BMSB populations collected from 12 countries (2 native and 10 invaded) across four continents with the ultimate aim to trace the origin of BMSBs intercepted during border inspections and post-border surveillance. RESULT: A total of 1775 high confidence single nucleotide polymorphisms (SNPs) were identified from ddRAD sequencing data collected from 389 adult BMSB individuals. Principal component analysis (PCA) of the identified SNPs indicated the existence of two main distinct genetic clusters representing individuals sampled from regions where BMSB is native to, China and Japan, respectively, and one broad cluster comprised individuals sampled from countries which have been invaded by BMSB. The population genetic structure analysis further discriminated the genetic diversity among the BMSB populations at a higher resolution and distinguished them into five potential genetic clusters. CONCLUSION: The study revealed hidden genetic diversity among the studied BMSB populations across the continents. The BMSB populations from Japan were genetically distant from the other studied populations. Similarly, the BMSB populations from China were also genetically differentiated from the Japanese and other populations. Further genetic structure analysis revealed the presence of at least three genetic clusters of BMSB in the invaded countries, possibly originating via multiple invasions. Furthermore, this study has produced novel set of SNP markers to enhance the knowledge of genetic diversity among BMSB populations and demonstrates the potential to trace the origin of BMSB individuals for future invasion events.