Data from: Differences in caste dimorphism among three hornet species (Hymenoptera: Vespidae): forewing size, shape and allometry

Caste shape dimorphism (CShD) has previously been studied in wasps through comparison of different body parts, originating from different imaginal discs. Using geometric morphometrics with a new protocol for measuring wings of pinned specimens from natural history collections, we tested CShD of three hornet species in an organ developed from a single imaginal disc: the forewing. Gaussian Mixture Models retrieved most castes and species levels confirming that caste is an important component of wing variations in females of these hornets. Size and allometry – the influence of size on shape – contribution to wing dimorphism between castes was major, but failed to explain the entire shape dimorphism. This deviation from simple allometric scaling was not similar in the three species: in Vespa tropica, allometric directions in the shape space differed between castes, while in V. crabro and V. velutina they were similar but a significant part of CShD resulted from lateral transpositions. These results clearly indicate that queens are not just enlarged workers. They also support that the different pattern of CShD may result from different developmental mechanism. Finally, they highlight that even in a highly social group like hornets there is still variation in caste dimorphism among species.

品级形状二态性（Caste shape dimorphism, CShD）此前已在胡蜂类群中通过比较源自不同成虫盘的多个身体部位开展研究。本研究采用面向自然历史馆藏针插标本翅部测量的全新实验流程，结合几何形态测量学方法，针对由单个成虫盘发育而来的器官——前翅，检验了3种胡蜂的CShD。高斯混合模型（Gaussian Mixture Models）成功区分出绝大多数品级与物种类群，证实品级是此类胡蜂雌性翅部形态变异的重要影响因素。体型以及异速生长——即体型对形态的调控作用——对品级间翅部二态性的贡献占据主导，但无法解释全部的形状二态性。这种偏离简单异速生长缩放规律的现象在3个物种中并不一致：在热带胡蜂（Vespa tropica）中，品级间的形态空间异速生长方向存在显著差异；而在大虎头蜂（Vespa crabro，原文缩写V. crabro）和黄脚胡蜂（Vespa velutina，原文缩写V. velutina）中，异速生长方向相似，但CShD的显著组分源于形态空间的侧向移位。上述结果明确表明，蜂王并非仅仅是体型增大的工蜂。同时本研究也支持，不同的CShD模式可能源自不同的发育调控机制。最后，研究结果还凸显出，即便在胡蜂这类高度社会性类群中，不同物种间的品级二态性仍存在显著差异。