Invasive insect genetics: Start codon targeted (SCoT) markers provide superior data to describe genetic diversity of brown marmorated stink bug, Halyomorpha halys, in a newly colonized region

Brown marmorated stink bug (BMSB), Halyomorpha halys Stal (Hemiptera: Pentatomidae), is a significant invasive agricultural pest affecting diverse crops globally. Halyomorpha halys rapidly invaded the Black Sea agricultural region of Türkiye, necessitating investigation of invasion pathways using complementary molecular approaches. We employed a novel approach on insect genetics—start codon targeted (SCoT) markers—to assess intraspecific genetic diversity among 71 BMSB specimens from 12 Turkish provinces and analyzed mitochondrial cytochrome c oxidase subunit I (COI) regions from nine specimens and integrating previously published data to construct a phylogenetic TCS network. SCoT markers revealed substantial genetic diversity (91.4% polymorphic fragments), identifying six distinct genetic clusters within Turkish populations. Analysis of molecular variance showed significant population structuring at the provincial level but limited differentiation regionally. The Western Black Sea region exhibited highest genetic diversity, with Trabzon identified as a variation hotspot. Conversely, COI-based TCS analysis showed all Turkish specimens belonged exclusively to the dominant Hap_1 lineage prevalent in most invaded countries worldwide. The marker systems highlight improved resolution of SCoT markers in detecting recent genetic diversification not apparent through mitochondrial analysis alone. This novel genetic approach enhances understanding of BMSB invasion pathways in the Black Sea region of Türkiye. Understanding invasion dynamics and genetic variation with worldwide BMSB samples would provide crucial information for developing targeted management measures. Our results demonstrate the potential utility of SCoT markers for detecting intraspecific genetic diversity within regional insect populations. This preliminary assessment, based on 71 specimens for SCoT analysis and nine representative specimens for COI sequencing, provides foundational evidence for the superior resolution of SCoT markers in invasion genetics studies.