Out of the dark: 350 million years of conservatism and evolution in diel activity patterns in vertebrates

Many animals are active only during a particular time (e.g. day vs. night), a partitioning that may have important consequences for species co-existence. An open question is the extent to which this diel activity niche is evolutionarily conserved or labile. Here, we analyze diel activity data across a phylogeny of 1914 tetrapod species. We find strong phylogenetic signal, showing that closely related species tend to share similar activity patterns. Ancestral reconstructions show that nocturnality was the most likely ancestral diel activity pattern for tetrapods and many major clades within it (e.g. amphibians, mammals). Remarkably, nocturnal activity appears to have been maintained continuously in some lineages for ~350 million years. Thus, we show that traits involved in local-scale resource partitioning can be conserved over strikingly deep evolutionary time scales. We also demonstrate a potentially important (but often overlooked) metric of niche conservatism. Finally, we show that d...

诸多动物仅在特定时段（如昼间与夜间）活跃，这种资源分隔模式可能对物种共存具有重要意义。目前尚存一个开放性问题：这类昼夜活动生态位（diel activity niche）在演化上究竟是保守的，还是易变的。本研究针对涵盖1914种四足动物（tetrapod）的系统发育树所收录的昼夜活动数据展开分析。我们检测到显著的系统发育信号（phylogenetic signal），表明亲缘关系较近的物种往往拥有相似的活动模式。祖先特征重建结果显示，夜行性（nocturnality）是四足动物及其诸多主要类群（如两栖类、哺乳类）最可能的祖先昼夜活动模式。值得注意的是，部分演化支的夜行性活动模式已持续维持了约3.5亿年。据此，我们证实：参与局域尺度资源划分的性状，可在极深的演化时间尺度上得到保守保留。此外，本研究还揭示了一项潜在重要但常被忽视的生态位保守性（niche conservatism）衡量指标。最后，我们发现……