Multi-locus nuclear barcode assessment of genetic diversity in Swiss Orthoptera unveils conservation status limitations

With accelerating biodiversity loss, tracking both inter- and intraspecific diversity is critical, as within-species variation underpins population viability and adaptive potential. Traditional single-locus barcoding, targeting short mitochondrial or plastid fragments, generally provides reliable species-level resolution but poorly captures intraspecific variation. To address this, we developed an Orthoptera-specific marker panel targeting 398 nuclear loci plus the complete mitogenome and ribosomal DNA, sequencing these regions in 645 specimens representing every Swiss Orthoptera species sampled during the nationwide Red List update. This multilocus dataset produced a well-supported phylogeny and resolved several taxonomic ambiguities with direct conservation relevance. Genetic variation was further used to infer population structure and to test whether intraspecific diversity correlates with ecological traits and Red List status. While species’ IUCN threat levels were not correlated with genetic diversity, we found a significant negative association between genetic diversity and dependence on riparian habitats: river-bank specialists showed lower diversity, likely reflecting the severe fragmentation and alteration of these ecosystems. Our results demonstrate that genetic diversity measures from multilocus markers provide valuable, complementary insights into conservation status. However, the lack of correlation with IUCN threat levels highlights a challenge for integrating genetic data into Red List assessments: while low diversity often flags advanced decline and urgent action, high diversity does not necessarily signal low extinction risk, as it can persist for some time after population decline. Genomic data should therefore be incorporated cautiously alongside traditional criteria. These findings are being integrated into the upcoming Swiss Orthoptera Red List update.随着全球生物多样性丧失速率持续加快，同步追踪物种间与物种内的多样性已成为至关重要的研究方向——种内变异是种群存续能力与适应潜力的核心基础。传统单基因座条形码技术（single-locus barcoding）通常靶向短线粒体或质体片段（mitochondrial or plastid fragments），虽可实现可靠的物种级分辨率，却难以捕捉种内遗传变异。为解决这一局限，我们开发了一套直翅目（Orthoptera）特异性标记面板，靶向398个核基因座以及完整线粒体基因组（mitogenome）与核糖体DNA（ribosomal DNA）；我们对645份标本的上述区域进行了测序，这些标本涵盖了全国红色名录更新期间采集到的全部瑞士直翅目物种。这套多基因座数据集构建了支持度优异的系统发育树，并解决了若干具有直接保护相关意义的分类学歧义问题。我们进一步利用遗传变异数据推断种群结构，并检验种内多样性是否与生态性状及红色名录等级存在关联。尽管物种的国际自然保护联盟（International Union for Conservation of Nature，简称IUCN）威胁等级与遗传多样性并无显著相关性，但我们发现遗传多样性与河岸生境依赖性之间存在显著负相关：河岸专性物种的遗传多样性更低，这大概率反映了这类生境严重的碎片化与人为改造。本研究结果证实，基于多基因座标记的遗传多样性评估能够为物种保护现状提供极具价值的补充性见解。然而，遗传多样性与IUCN威胁等级缺乏相关性的结论，也为将遗传数据整合进红色名录评估工作带来了挑战：低遗传多样性往往预示着种群已处于严重衰退阶段，亟需采取保护行动，但高遗传多样性并不必然意味着低灭绝风险——种群衰退后的一段时间内，遗传多样性仍可能维持在较高水平。因此，基因组数据应当与传统评估标准谨慎结合使用。目前，这些研究发现正被整合进即将更新的瑞士直翅目红色名录。