Many developmental traits that are critical to the survival of the organism are also robust. These robust traits are resistant to phenotypic change in the face of variation. This presents a challenge to evolution. In this article, we asked whether and how a well‐established robust trait, Drosophila segment patterning, changed over the evolutionary history of the genus. We compared segment position scaled to body length at the first‐instar larval stage among 12 Drosophila species. We found that relative segment position has changed many times across the phylogeny. Changes were frequent, but primarily small in magnitude. Phylogenetic analysis demonstrated that rates of change in segment position are variable along the Drosophila phylogenetic tree, and that these changes can occur in short evolutionary timescales. Correlation between position shifts of segments decreased as the distance between two segments increased, suggesting local control of segment position. The posterior‐most abdominal segment showed the highest magnitude of change on average, had the highest rate of evolution between species, and appeared to be evolving more independently as compared to the rest of the segments. This segment was exceptionally elongated in the cactophilic species in our dataset, raising questions as to whether this change may be adaptive.

中文翻译：

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12 种果蝇幼虫节段位置的演变

许多对生物体生存至关重要的发育特征也很强大。这些强大的特征在面对变异时能够抵抗表型变化。这对进化提出了挑战。在本文中，我们询问了一个完善的稳健性状果蝇节段模式是否以及如何在该属的进化历史中发生变化。我们比较了 12 种果蝇在第一龄幼虫阶段与体长成比例的节段位置。我们发现相对片段位置在整个系统发育过程中发生了多次变化。变化是频繁的，但主要是规模较小。系统发育分析表明，沿果蝇系统发育树，节段位置的变化率是可变的，并且这些变化可以在很短的进化时间尺度内发生。随着两段之间的距离增加，段位置偏移之间的相关性降低，表明段位置的局部控制。最后腹部的平均变化幅度最大，物种之间的进化速度最高，并且与其余部分相比，似乎更独立地进化。在我们的数据集中，这一部分在嗜食性物种中被特别拉长，引发了关于这种变化是否具有适应性的问题。并且与其他细分市场相比，似乎更加独立地发展。在我们的数据集中，这一部分在嗜食性物种中被特别拉长，引发了关于这种变化是否具有适应性的问题。并且与其他细分市场相比，似乎更加独立地发展。在我们的数据集中，这一部分在嗜食性物种中被特别拉长，引发了关于这种变化是否具有适应性的问题。