Stag beetles show great developmental plasticity (DP) in their external morphology. In intraspecific evolution, DP functions as a stabilizer for morphological change, whereas interspecifically, the evolution of external morphology is primarily a process of differentiation in DP. Greater DP in external morphology has evolved as a species trait through selection for survival in conditions that vary stochastically, rather than a long-term unidirectional trend in conditions. All the interspecific transitions towards larger size, multimodal morphology and adaptive expansion are preceded by an increase in DP. Here, differentiation of DP is more a cause, rather than a result, of species-level evolution. This contrasts with the differentiation of other important traits, such as the morphology of the genitalia, which follow the conventional known process of small effects accumulating to larger effects from an intraspecific stage to an interspecific stage, in which DP plays no significant role. The DP of external morphology, as an emergent property of species, provides the means by which they can survive and subsequently evolve to be better adapted to novel conditions. This contrasting mode of evolution through differentiation of DP should play a crucial role in species survival and the maintenance of biodiversity in the Anthropocene.

中文翻译：

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发育可塑性的差异是锹形甲虫形态进化的主要原因。（鞘翅目：Lucanidae）

锹形甲虫在其外部形态上显示出很大的发育可塑性（DP）。在种内进化中，DP充当形态变化的稳定剂，而种间而言，外部形态的进化主要是DP分化的过程。通过选择在随机变化的条件下生存而不是长期的单向趋势，外部形态上的较大DP已演变为物种特征。向大尺寸，多峰形态和适应性扩展的所有种间过渡之前都有DP的增加。在这里，DP的分化更多是物种级进化的原因，而不是结果。这与其他重要特征的分化形成鲜明对比，例如生殖器的形态，它们遵循常规已知的小效应积累过程，从种内阶段到种间阶段，到更大的阶段，DP在其中不起作用。作为物种的一种新兴特性，外部形态学的DP提供了它们可以生存并随后进化为更好地适应新条件的手段。这种通过DP分化而形成的相反的进化模式应该在人类世代的物种生存和生物多样性的维持中发挥关键作用。