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不同身体部位开展过研究，这些身体部位源自不同的成虫盘。本研究采用几何形态测量学方法，并结合一套针对自然历史馆藏针插标本的翅部测量新规程，针对由单个成虫盘发育而来的前翅这一器官，检验了3种胡蜂的品级形状二态性。高斯混合模型成功区分了绝大多数品级与物种类群，证实品级是这类胡蜂雌性个体翅部形态变异的重要组成部分。体型与异速生长（即体型对形态的影响）对品级间翅部二态性的贡献占据主导地位，但无法解释全部的形状二态性。这种偏离简单异速缩放的模式在3个物种中并不一致：在热带胡蜂（Vespa tropica）中，形态空间内的异速生长方向在不同品级间存在差异；而在欧洲胡蜂（Vespa crabro）与黄腰胡蜂（Vespa velutina）中，该方向虽相似，但品级形状二态性的显著部分源于侧向移位。这些结果明确表明，蜂后并非仅仅是体型被放大的工蜂。它们同时佐证，品级形状二态性的不同模式可能源于不同的发育机制。最后，本研究结果凸显，即便在胡蜂这类高度社会化的类群中，不同物种间的品级二态性仍存在差异。