Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA.
Departments of Biology and Earth System Science, Stanford University, Stanford, California, USA.
J Evol Biol. 2023 May;36(5):829-841. doi: 10.1111/jeb.14171.
Sexual dimorphism (SD) is a common feature of animals, and selection for sexually dimorphic traits may affect both functional morphological traits and organismal performance. Trait evolution through natural selection can also vary across environments. However, whether the evolution of organismal performance is distinct between the sexes is rarely tested in a phylogenetic comparative context. Anurans commonly exhibit sexual size dimorphism, which may affect jumping performance given the effects of body size on locomotion. They also live in a wide variety of microhabitats. Yet the relationships among dimorphism, performance, and ecology remain underexamined in anurans. Here, we explore relationships between microhabitat use, body size, and jumping performance in males and females to determine the drivers of dimorphic patterns in jumping performance. Using methods for predicting jumping performance through anatomical measurements, we describe how fecundity selection and natural selection associated with body size and microhabitat have likely shaped female jumping performance. We found that the magnitude of sexual size dimorphism (where females are about 14% larger than males) was much lower than dimorphism in muscle volume, where females had 42% more muscle than males (after accounting for body size). Despite these sometimes-large averages, phylogenetic t-tests failed to show the statistical significance of SD for any variable, indicating sexually dimorphic species tend to be closely related. While SD of jumping performance did not vary among microhabitats, we found female jumping velocity and energy differed across microhabitats. Overall, our findings indicate that differences in sex-specific reproductive roles, size, jumping-related morphology, and performance are all important determinants in how selection has led to the incredible ecophenotypic diversity of anurans.
性二型（SD）是动物的一个共同特征，对性二型特征的选择可能会影响功能形态特征和机体表现。自然选择引起的性状进化也可能因环境而异。然而，在系统发育比较的背景下，生物体性能的进化是否在两性之间存在明显差异，这一点很少得到检验。蛙类通常表现出性大小二型，由于体型对运动的影响，这可能会影响跳跃性能。它们还生活在各种各样的微生境中。然而，在蛙类中，二型、性能和生态学之间的关系仍然研究不足。在这里，我们探讨了雄性和雌性在微生境利用、体型和跳跃性能之间的关系，以确定跳跃性能二型模式的驱动因素。我们使用通过解剖测量预测跳跃性能的方法，描述了与体型和微生境相关的繁殖力选择和自然选择如何塑造雌性跳跃性能。我们发现，性大小二型的幅度（雌性比雄性大约大 14%）远低于肌肉体积的二型，雌性的肌肉比雄性多 42%（在考虑了体型之后）。尽管这些平均值有时很大，但系统发育 t 检验未能显示任何变量的 SD 具有统计学意义，这表明性二型物种往往彼此密切相关。虽然跳跃性能的 SD 没有在微生境之间变化，但我们发现雌性的跳跃速度和能量在微生境之间存在差异。总的来说，我们的研究结果表明，在性特异性生殖角色、体型、与跳跃相关的形态和性能方面的差异，都是选择导致蛙类令人难以置信的生态表型多样性的重要决定因素。
