The University Museum, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.
J Morphol. 2023 Aug;284(8):e21616. doi: 10.1002/jmor.21616.
Winter geometrid moths show striking sexual dimorphism by having female-specific flightless morphs. The evolutionary grades of wing reduction in winter geometrid moths vary and range from having short wings, vestigial wings, to being wingless. Although the ontogenetic processes underlying the development of the wingless or short-wing morphs in Lepidoptera has been well studied, the mechanisms underlying the development of vestigial wing morphs in winter geometrid moths during metamorphosis are poorly understood. In the winter geometrid moth Sebastosema bubonaria Warren, 1896, the males have functional wings, but the females have vestigial wings. Here, we studied the ontogenetic processes affecting wing reduction in the winter geometrid moth S. bubonaria using light microscopy and transmission electron microscopy, and compared the ontogenetic process of wing reduction in this species with that in another species of the wingless-female winter moth that we investigated previously. Our results showed that, in the vestigial-wing morphs, the loss of pupal wing epithelium was terminated in the middle of the wing degeneration process, whereas in the wingless morph, the pupal wing epithelium disappeared almost completely and the final appearance of the wings differed slightly among flightless morphs. We propose that the extent and location of cell death in the pupal wing play an important role in the various patterns of reduced wings that are observed in flightless moths.
冬季尺蠖蛾类表现出明显的性别二态性，具有雌性特有的无飞行形态。冬季尺蠖蛾类的翅膀退化程度不同，从短翅、残翅到无翅不等。尽管鳞翅目无翅或短翅形态发育的个体发生过程已经得到很好的研究，但在变态过程中冬季尺蠖蛾类残翅形态的发育机制还知之甚少。在冬季尺蠖蛾 Sebastosema bubonaria Warren, 1896 中，雄性有功能性翅膀，而雌性则有残翅。在这里，我们使用光学显微镜和透射电子显微镜研究了影响冬季尺蠖蛾 S. bubonaria 翅膀退化的个体发生过程，并将该物种翅膀退化的个体发生过程与我们之前研究过的另一种无翅雌性冬季蛾的个体发生过程进行了比较。我们的结果表明，在残翅形态中，蛹翅上皮组织的丧失在翅膀退化过程的中间阶段终止，而在无翅形态中，蛹翅上皮组织几乎完全消失，并且在无翅形态中翅膀的最终外观略有不同。我们提出，蛹翅中细胞死亡的程度和位置在无翅蛾中观察到的各种翅膀退化模式中起着重要作用。
