Homology of the internal sac components in the leaf beetle subfamily criocerinae and evolutionary novelties related to the extremely elongated flagellum
Homology of the internal sac components in the leaf beetle subfamily criocerinae and evolutionary novelties related to the extremely elongated flagellum
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DOI：
10.1002/jmor.11037
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发表时间：
2012-05-01
影响因子：
1.5
通讯作者：
Yoshizawa, Kazunori
中科院分区：
文献类型：
--
作者：
Matsumura, Yoko;Yoshizawa, Kazunori
极细长的内陷器官在许多种类中被发现，特别是在昆虫中。这种现象通常被认为是性选择的结果，但据预测，体腔中有限的存储空间和使用细长器官的困难应该限制了极端伸长的进化，抵消了任何选择优势。因此，在具有较长的插入器官的群体中，克服这些限制的特征可能与插入器官的伸长一起进化或共同进化。使用比较形态学的方法和外群比较，我们确定了潜在的限制和关键的新颖性，可能会抵消这种限制在叶甲亚科Criocerinae。对整个Criocerinae的内部囊结构进行了观察。与以前的研究结果进行比较，从外群体，地面计划的cricocellular内囊的构建。我们的分析还确定了与极端伸长相关的特定特征：整个内囊片的旋转和拥有一个储存伸长鞭毛的口袋。囊袋被认为是由骨片的旋转形成的，明显地改变了来自criocerebral平面的内部囊的形状。只有已经获得这种派生状态的分支包含明显超过中裂片长度的细长鞭毛的物种。据推测，这些性格相关性独立进化了三次。检测到的字符相关性证实了这一假设，即有潜在的适应性限制的进化极其细长的transmittent器官。这些限制可能已经被从criocampus地面平面图的改变中抵消，导致形成一个存储口袋。总之，偏离criocerium地面计划被认为是进化的创新，中和了潜在的适应性限制鞭毛伸长的亚科Criocerinae。J. Morphol.，2012. (c)2011 Wiley Periodicals，Inc.
Extremely elongated intromittent organs are found in a wide range of taxa, especially among insects. This phenomenon is generally thought to result from sexual selection, but it is predicted that limited storage space in the body cavity and the difficulty of using the elongated organs should have constrained the evolution of extreme elongation, neutralizing any selective advantage. Therefore, in groups with long intromittent organs, features that overcome these constraints may have evolved or coevolved together with intromittent organ elongation. Using a comparative morphological approach and outgroup comparisons, we identified potential constraints and key novelties that may neutralize such constraints in the leaf beetle subfamily Criocerinae. Observations of the internal sac structure throughout Criocerinae were performed. Comparing the results with preceding studies from outgroups, a ground plan of the criocerine internal sac was constructed. Our analysis also identified specific features that are always correlated with extreme elongation: the rotation of whole internal-sac sclerites and the possession of a pocket in which to store the elongated flagellum. The pocket is thought to be formed by the rotation of the sclerites, markedly altering internal sac shape from the criocerine ground plan. Onlythe clades that have acquired this derived state contain species with an elongated flagellum that distinctly exceeds the median lobe length. It is presumed that these character correlations evolved independently three times. The detected character correlations corroborate the hypothesis that there are latent adaptive constraints for the evolution of extremely elongated intromittent organs. The constraints may have been neutralized by the alteration from the criocerine ground plan resulting in the formation of a storage pocket. In conclusion, deviation from the criocerine ground plan isconsidered to be the evolutionary innovation that neutralized the latent adaptive constraints of flagellum elongation in the subfamily Criocerinae. J. Morphol., 2012. (c) 2011 Wiley Periodicals, Inc.