Data from: Mechanical sensitivity reveals evolutionary dynamics of mechanical systems

A classic question in evolutionary biology is how form–function relationships promote or limit diversification. Mechanical metrics, such as kinematic transmission (KT) in linkage systems, are useful tools for examining the evolution of form and function in a comparative context. The convergence of disparate systems on equivalent metric values (mechanical equivalence) has been highlighted as a source of potential morphological diversity under the assumption that morphology can evolve with minimal impact on function. However, this assumption does not account for mechanical sensitivity—the sensitivity of the metric to morphological changes in individual components of a structure. We examined the diversification of a four-bar linkage system in mantis shrimp (Stomatopoda), and found evidence for both mechanical equivalence and differential mechanical sensitivity. KT exhibited variable correlations with individual linkage components, highlighting the components that influence KT evolution, and the components that are free to evolve independently from KT and thereby contribute to the observed pattern of mechanical equivalence. Determining the mechanical sensitivity in a system leads to a deeper understanding of both functional convergence and morphological diversification. This study illustrates the importance of multi-level analyses in delineating the factors that limit and promote diversification in form–function systems.

进化生物学中的一个经典问题是，形态-功能关系如何促进或限制演化分异。诸如连杆系统中的运动学传递率（kinematic transmission, KT）这类力学指标，是在比较研究框架下探究形态与功能演化的有效工具。不同演化体系趋同至等价的指标数值（即力学等价性），曾被视作潜在形态多样性的来源，其隐含假设为形态结构的演化可对功能产生极小影响。然而，这一假设未考虑力学敏感性——即该指标对结构单个组成部分形态变化的敏感程度。我们以螳螂虾（Stomatopoda）的四连杆系统为研究对象，发现了力学等价性与差异化力学敏感性并存的证据。运动学传递率（KT）与各个连杆组分的相关性存在显著差异，这揭示了哪些组分可影响KT的演化，以及哪些组分可脱离KT独立演化，进而促成了观测到的力学等价性模式。解析系统的力学敏感性，有助于更深入地理解功能趋同与形态分异二者。本研究阐明了多维度分析在阐明形态-功能系统中限制与促进演化分异的因素时的重要性。