Despite the urgent need for conservation consideration, strategic action plans for the preservation of the Asian honeybee, Apis cerana Fabricius, 1793, remain lacking. Both the convergent and divergent adaptations of this widespread insect have led to confusing phenotypical traits and inconsistent infraspecific taxonomy. Unclear subspecies boundaries pose a significant challenge to honeybee conservation efforts, as it is difficult to effectively prioritize conservation targets without a clear understanding of subspecies identities. Here, we investigated genome variations in 362 worker bees representing almost all populations of mainland A. cerana to understand how evolution has shaped its population structure. Whole-genome single nucleotide polymorphisms (SNPs) based on nuclear sequences revealed eight putative subspecies, with all seven peripheral subspecies exhibiting mutually exclusive monophyly and distinct genetic divergence from the widespread central subspecies. Our results demonstrated that most classic morphological traits, including body size, were related to the climatic variables of the local habitats and did not reflect the true evolutionary history of the organism. Thus, such morphological traits were not suitable for subspecific delineation. Conversely, wing vein characters showed relative independence to the environment and supported the subspecies boundaries inferred from nuclear genomes. Mitochondrial phylogeny further indicated that the present subspecies structure was a result of multiple waves of population divergence from a common ancestor. Based on our findings, we propose that criteria for subspecies delineation should be based on evolutionary independence, trait distinction, and geographic isolation. We formally defined and described eight subspecies of mainland A. cerana. Elucidation of the evolutionary history and subspecies boundaries enables a customized conservation strategy for both widespread and endemic honeybee conservation units, guiding colony introduction and breeding.
对东方蜜蜂 Apis cerana Fabricius, 1793的保护迫在眉睫，但仍缺乏切实可行的行动方案。这种广域分布的昆虫同时具有趋同和趋异适应的特征，很大程度上造成了形态表型特征的混淆和亚种分类地位的混乱。模糊的亚种界限危及到蜜蜂保护的基础，如果我们无法明确目标和优先级，就无法保护它们。在该研究中，我们调查了来自东方蜜蜂亚洲大陆支系主要种群的362头工蜂的基因组单碱基核苷酸变异，以解析进化历史是如何塑造其种群结构的。研究基于核基因组 SNPs 初步划分了八个亚种级别的遗传单元，其中七个边缘单元均表现出独立的单系性，并与广域分布的中部单元之间存在显著的遗传分化。同时，我们证明：包括体型大小等性状在内的大部分经典蜜蜂形态特征，都与所属生境的气候特征存在密切关联。此类特征并不能反映种群间真实的演化关系，故不适用于亚种的界定。相反，翅脉特征表现出对环境的相对独立性，并支持了核基因组数据所界定的亚种划分。线粒体系统发生分析进一步表明，目前的亚种结构是共同祖先种群经历多次独立分化的结果。根据该研究的发现，我们提出了使用演化独立性、有效形态特征和地理隔离作为亚种划分证据的方法。我们正式定义和描述了东方蜜蜂亚洲大陆支系的八个亚种。阐明东方蜜蜂的演化历史和亚种定义，有助于为广域和局域性分布的蜜蜂遗传单元提供定制化的保护策略，并指导蜂群引种和繁育。.
Keywords: Apis cerana; Centrifugal diversification; Genomics; Integrative taxonomy; Morphology; Pollinator insect; Species concept.