Defining honeybee subspecies in an evolutionary context warrants strategized conservation
Lifei Qiu, 中国农业大学植物保护学院, 北京100193, 中国, Jiangxing Dong, Xingan Li, Sajad Hussain Parey, Ken Tan, Michael C. Orr, Aquib Majeed, Xue Zhang, Shiqi Luo, Xuguo Zhou, Chao‐Dong Zhu, Ting Ji, Qingsheng Niu, Shanlin Liu, Xin Zhou, 吉林省养蜂科学研究所蜜蜂遗传育种重点实验室, 吉林 吉林 132108, 中国, 中国科学院西双版纳热带植物园, 中国科学院热带森林生态学重点实验室, 云南 昆明650000, 中国, 中国科学院动物研究所, 中国科学院动物进化与系统学重点实验室, 北京 100101, 中国, 扬州大学, 江苏 扬州225009, 中国
Abstract
Despite the urgent need for conservation consideration, strategic action plans for the preservation of the Asian honeybee, <i>Apis cerana</i> 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 <i>A. cerana</i> 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 <i>A. cerana</i>. 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.