The common ancestor of spiders likely used silk to line burrows or make simple webs, with specialized spinning organs and aerial webs originating with the evolution of the megadiverse "true spiders" (Araneomorphae). The base of the araneomorph tree also concentrates the greatest number of changes in respiratory structures, a character system whose evolution is still poorly understood, and that might be related to the evolution of silk glands. Emphasizing a dense sampling of multiple araneomorph lineages where tracheal systems likely originated, we gathered genomic-scale data and reconstructed a phylogeny of true spiders. This robust phylogenomic framework was used to conduct maximum likelihood and Bayesian character evolution analyses for respiratory systems, silk glands, and aerial webs, based on a combination of original and published data. Our results indicate that in true spiders, posterior book lungs were transformed into morphologically similar tracheal systems six times independently, after the evolution of novel silk gland systems and the origin of aerial webs. From these comparative data we put forth a novel hypothesis that early-diverging web building spiders were faced with new energetic demands for spinning, which prompted the evolution of similar tracheal systems via convergence; we also propose tests of predictions derived from this hypothesis.

中文翻译：

---

真蜘蛛的序列捕获系统基因组学揭示了呼吸系统的趋同进化

蜘蛛的共同祖先可能使用丝绸来排列洞穴或制作简单的网，具有特殊的旋转器官和空中网，起源于大型多样性“真蜘蛛”（Araneomorphae）的进化。蛛形树的基部也集中了最多数量的呼吸结构变化，这种特征系统的进化仍然知之甚少，这可能与丝腺的进化有关。强调对可能起源于气管系统的多个蛛形纲谱系进行密集采样，我们收集了基因组规模的数据并重建了真正蜘蛛的系统发育。这个强大的系统发育框架被用来对呼吸系统、丝腺和空中网进行最大似然和贝叶斯特征进化分析，基于原始数据和已发布数据的组合。我们的研究结果表明，在真蜘蛛中，在新的丝腺系统进化和空中网的起源之后，后书肺独立地转化为形态相似的气管系统 6 次。从这些比较数据中，我们提出了一个新假设，即早期发散的建网蜘蛛面临着新的旋转能量需求，这促使类似的气管系统通过收敛而进化；我们还建议对从该假设得出的预测进行检验。从这些比较数据中，我们提出了一个新假设，即早期发散的建网蜘蛛面临着新的旋转能量需求，这促使类似的气管系统通过收敛而进化；我们还建议对从该假设得出的预测进行检验。从这些比较数据中，我们提出了一个新假设，即早期发散的建网蜘蛛面临着新的旋转能量需求，这促使类似的气管系统通过收敛而进化；我们还建议对从该假设得出的预测进行检验。