Armed stem to stinger: a review of the ecological roles of scorpion weapons

Abstract Scorpions possess two systems of weapons: the pincers (chelae) and the stinger (telson). These are placed on anatomically and developmentally well separated parts of the body, that is, the oral appendages and at the end of the body axis. The otherwise conserved body plan of scorpions varies most in the shape and relative dimensions of these two weapon systems, both across species and in some cases between the sexes. We review the literature on the ecological function of these two weapon systems in each of three contexts of usage: (i) predation, (ii) defense and (iii) sexual contests. In the latter context, we will also discuss their usage in mating. We first provide a comparative background for each of these contexts of usage by giving examples of other weapon systems from across the animal kingdom. Then, we discuss the pertinent aspects of the anatomy of the weapon systems, particularly those aspects relevant to their functioning in their ecological roles. The literature on the functioning and ecological role of both the chelae and the telson is discussed in detail, again organized by context of usage. Particular emphasis is given on the differences in morphology or usage between species or higher taxonomic groups, or between genders, as such cases are most insightful to understand the roles of each of the two distinct weapon systems of the scorpions and their evolutionary interactions. We aimed to synthesize the literature while minimizing conjecture, but also to point out gaps in the literature and potential future research opportunities.

摘要 蝎子拥有两套武器系统：螯肢（chelae）与尾刺（telson）。二者分别位于解剖结构与发育起源截然不同的两个身体部位，即口附肢与躯体轴末端。在蝎子整体保守的躯体构型中，这两套武器系统的形态与相对尺寸差异最为显著，不仅存在于不同物种之间，部分类群的雌雄个体间亦存在此类差异。我们综述了这两套武器系统在三类使用场景下的生态功能相关研究：（i）捕食、（ii）防御与（iii）性对抗，其中在性对抗场景中还将讨论其在交配过程中的作用。首先，我们通过列举动物界其他类群的武器系统案例，为上述三类使用场景提供比较生物学背景。随后，我们阐述了武器系统的解剖学特征，尤其是与其生态功能发挥相关的关键属性。我们将按照使用场景分类，详细讨论螯肢与尾刺的功能运作与生态角色相关的研究文献。本综述特别关注不同物种或高级分类群间、雌雄个体间在形态或使用方式上的差异——此类案例对于理解蝎子两套独特武器系统的功能及其演化交互关系具有重要启示意义。本研究旨在整合现有文献，尽可能减少主观臆断，同时指明当前研究存在的空白与潜在的未来研究方向。