Exploring species delimitation of high-altitude flower bugs (Heteroptera: Anthocoridae) in the presence of complex reticulate evolution: the case of a biodiversity hotspot in the Qinghai–Tibet Plateau and surrounding mountains

Abstract The flower bugs genus Anthocoris consists of small predatory insects with 2 major species groups, the A. nemorum group and the A. thibetanus group, are predominantly found in the high-altitude regions of the Qinghai–Tibet Plateau (QTP) and its surrounding mountains. Their small size and subtle morphological differences make it difficult to delimit species using only morphological characteristics, and no molecular studies have yet assessed whether the diversification of these groups was driven by the same period of plateau uplift. To address these challenges, this study employs comprehensive delimitation methods, including morphological analysis and single-locus and multilocus analyses, to classify species within the A. nemorum and A. thibetanus groups. Six new species are described: A. neomontanus Tang & Bu, sp. nov., A. neonemorum Tang & Bu, sp. nov., A. renae Tang & Bu, sp. nov., A. kangdingensis Tang & Bu, sp. nov., A. fuae Tang & Bu, sp. nov., A. liui Tang & Bu, sp. nov. Four data sets with hundreds of loci but fewer individuals, BPP may serve as a suitable delimitation method. Combined with our analyses of examined gene tree discordance, and divergence time estimations, the repeated rapid uplifts of the QTP and surrounding mountains are likely the primary drivers of the complex reticulate evolutionary history of these two species groups. Our findings indicate that a BUSCO library at the order level, based on genome skimming, can provide a sufficient number of loci and has the potential for effective species delimitation in cases involving complex reticulate evolution.