【目的】 大刀锹甲Dorcus hopei雄性的上颚和鞘翅长度存在显著的种内差异，本文旨在量化分析这些种内差异属于雄性三型，进一步通过实验研究它们在配偶竞争中的优势，为探索种内三型的共存机制提供参考。【方法】 测量90只雄性成虫的上颚和鞘翅长度，通过高斯混合模型和基于AIC准则优选模型，识别出雄性三型；在此基础上，设计雄性的配偶竞争实验，借助红外相机记录不同表型组合的雄性接近雌性的时间长度和行为，用各型雄性占有雌性的时间长度来分析它们在配偶竞争中的相对优势。【结果】 不连续的三分段模型对雄性成虫的上颚和鞘翅长度拟合最好（AIC最小），这说明大刀锹甲的雄性可分为三个表型：型具有发达的上颚和鞘翅，长度分别分14.70-18.84 cm和22.14-25.86 cm；型的明显短小，长度分别为4.88-8.99 cm和15.42-19.40 cm；型的则居于型和型之间，长度分别为11.67-15.99 cm和19.24-23.77 cm。配偶竞争实验表明，在二型雄性组合实验中，型接近雌性的时间显著长于型（P=0.007）和型（P=0.003），型接近雌性的时间显著长于型（P=0.015）。有趣的是，在三型组合实验中，当型与另外两型雄性共存时，其接近雌性的时间最长，这说明型虽然是弱势竞争者，但可能因为其他两型的强烈竞争而间接获利。【结论】 大刀锹甲雄性存在明显的三型，且不同表型在配偶竞争的相对优势有强弱之分（型﹥型﹥型），但竞争弱的型可能是通过利用强者之间的竞争而获得机会。

[Objectives]  To investigate whether the stag beetle Dorcus hopei -coexists male trimorphism due to their remarkable variation in mandible and elytra length, and if so, to determine the relative success of each morph in mate competition. [Methods]  90 male specimens were classified into three putative morphs on the basis of mandible and elytra length. Male mating behavior was then filmed using an infrared camera and the relative competitive advantage of each morph assessed by measuring how long each took to approach female. [Results]  -type males have well-developed mandibles (14.70-18.84 cm long) and elytra (22.14-25.86 cm long), whereas -type males have rudimentary mandibles (4.88-8.99 cm long) and elytra (15.42-19.40 cm long), and -type males are intermediate in mandible (11.67-15.99 cm) and elytra (19.24-23.77 cm) length.  males spent more time in close proximity to females than  and  males, and  males spent more time in close proximity to females than  males. When  males coexisted with other two male morphs, they always took more time to approach females. The observations implied the males at a disadvantage might benefit indirectly from the strong competition between two advantaged males.. [Conclusion]  Our results suggested that the males of D. hopei are trimorphic, with three distinct male morphs simultaneously present in the population. Morphs could be ranked in terms of competitive superiority as follows: >>. We speculated that males as the less strong type would gain opportunities by drawing on the competition between two competitive morphs.. Further studies will be needed to understand the mating behavior and tactics among three male morphs. This is the first report of male trimorphism in the Chinese stag beetle. Our findings provide insights into the understanding and knowledge of multiple phenotypes coexisting within the same species.