Morphological identification and genetic evolutionary analysis of three black western bee（<italic>Apis mellifera</italic>）species in China

<bold>Objective</bold> There are three groups of black honeybees，namely the Northeast Black Bee（<italic>Apis mellifera-northeast black bee</italic>），the Xinjiang Black Bee（<italic>Apis mellifera-Xinjiang Black Bee</italic>），and the Black western honeybee（<italic>Apis mellifera sinisxinyuan</italic>）in China.This study aims to conduct a comprehensive comparative analysis of these three black western honeybee species through integrated morphological and molecular biological methods to gain a deeper understanding of their evolutionary relationships and adaptive characteristics. <bold>Method</bold> In this study，18 morphological traits of the three black honeybee groups were measured and compared，with the Italian bee（<italic>Apis mellifera ligustica</italic>）serving as a control.Concurrently，mitochondrial genes（<italic>ND2</italic>，<italic>COI</italic>，and <italic>COI-COII</italic> intergenic sequences）were analyzed to investigate their genetic structure and evolutionary relationships. <bold>Result</bold> （1）Morphological analysis revealed that the Xinjiang Black Bee and Northeast Black Bee are similar in most morphological traits and generally larger than the Black western honeybee.All three black bee species showed significant differences from the Italian bee in certain key features（such as proboscis length and number of wing hooks），reflecting possible local environmental adaptations.（2）Genetic analysis unveiled a more complex evolutionary pattern.ND2 sequence-based analysis showed the closest phylogenetic relationship between the Xinjiang Black Bee and Northeast Black Bee，which is consistent with morphological results.However，analyses of the COI and COI-COII intergenic sequences indicated varying degrees of genetic overlap with the Italian bee，with the Black western honeybee as an exception.The Black western honeybee consistently clustered independently in all genetic analyses，suggesting it may have undergone a unique evolutionary process. <bold>Conclusion</bold> Both Xinjiang black bee and Northeast black bee can be classified within the C lineage；while Western black bees belong to the M lineage，which may have undergone a unique adaptive evolutionary process，thus demonstrating distinct genetic backgrounds and morphological traits.These findings not only deepen our understanding of the genetic diversity of native Chinese honeybee species but also provide important scientific basis for honeybee conservation and breeding efforts.The results highlight the importance of preserving native honeybee genetic resources while offering new insights for future breeding strategies.