《生命科学》 2026, 38(1): 27-35
两栖动物性二型的研究进展
摘 要：
两栖动物性二型（sexual dimorphism）是指同种雌雄个体间在形态、行为及生理功能等方面表现出的稳定差异，是动物行为学、神经生物学、进化生物学和生态学研究的重要内容。作为自然选择与性选择共同作用的产物，性二型直接关乎个体的生存与繁殖，并深刻影响种群演化。近年来，随着分子生物学和多组学技术的发展，性二型的形成机制得到了更为深入的阐释。本文综述了两栖动物性二型的主要类型、生态及进化意义，聚焦于环境因素对性二型可塑性的影响，并深入评述了其分子调控机制的最新进展。在此基础上，本文展望了未来的研究方向，以期为两栖动物多样性保护及相关生物学基础研究提供理论参考。
通讯作者：闫承志 , Email:ychzhi@cwnu.edu.cn
Abstract:
Sexual dimorphism (SD) in amphibians encompasses consistent differences in morphology, behavior, and physiological functions between sexes. As a fundamental topic in evolutionary biology and ecology, SD arises from the interplay of natural and sexual selection, and exerts profound effects on individual fitness, population dynamics, and evolutionary trajectories. Amphibians, with their dual aquatic-terrestrial life history and high environmental sensitivity, provide a valuable model for exploring the evolutionary drivers of SD and the role of phenotypic plasticity. Although patterns of amphibian SD have been extensively described, knowledge remains limited on how environmental factors influence trait plasticity and the molecular networks linking genotype to phenotype. Drawing upon morphological, ecological, and multiomics evidence, this study systematically reviews the diversity of SD forms in amphibians, analyses its ecological and evolutionary drivers, and highlights recent advances in understanding environment-driven plasticity and molecular regulation under global climate change. Amphibian SD exhibits considerable diversity in form and function. Sexual size dimorphism (SSD) is the most widespread pattern, with approximately 90% of anuran species having females larger than males, generally driven by fecundity selection to maximize egg production. In contrast, species with strong male-male competition evolve larger males through sexual selection. Structural dimorphism often involves male-specific traits that enhance mating success, such as keratinized maxillary spines in Leptobrachium leishanense for combat. Morphological and physiological divergence can directly shape individual survival and reproductive strategies, as shown in Xenopus laevis, where males and females exhibit differential sensitivity to specific frequency ranges of the courtship calls.SD in amphibians is highly plastic in response to both climatic and non-climatic environmental change. Temperature and precipitation are major climatic drivers. In
regions with high temperature seasonality, males may show proportionally greater size increase than females, whereas spatial or temporal variation in rainfall can alter breeding season length and sex-specific growth rates, as reported for Lithobates sylvaticus. Non-climatic pressures, including habitat fragmentation and island isolation, can alter SD patterns; island populations of Odorrana schmackeri show notable female dwarfism due to limited food resources, reducing SSD. Predation risk can constrain the development of sexual traits or favor defensive adaptations, such as enlarged toxin glands in Epidalea calamita or altered coloration strategies.Recent advances in molecular biology and multi-omics approaches have enabled deeper insights into the underlying mechanisms driving SD. Sex-determining genes such as dm-w and dmrt1 in Xenopus trigger cascades of sex differentiation during embryonic development. Sex hormones regulate the development of external traits and influence neurosteroid pathways, thereby shaping courtship call production and auditory sensitivity thresholds in Hyla cinerea. Integrated transcriptomic and metabolomic data show that male-specific morphological traits are maintained through particular metabolic pathways. In Bufo gargarizans, the development of robust forelimb muscles for amplexus is associated with activation of energy metabolism and protein synthesis pathways involving genes such as AGXT and ACADL. In L. leishanense, spine formation is linked to Wnt signaling pathway activity and expansion of keratin gene families.In summary, amphibian SD arises from the integrated effects of genetic architecture, endocrine regulation, and environmental forces. While research has progressed from phenotypic description to mechanistic inquiry, significant knowledge gaps persist. These include the neural basis of sexually dimorphic behaviors, the contribution of epigenetic mechanisms to rapid adaptation and transgenerational effects, and the utility of SD traits as bioindicators in conservation. Addressing these questions will advance our understanding of SD evolution and inform effective conservation strategies in the face of ongoing environmental change.
Communication Author：YAN Cheng-Zhi , Email:ychzhi@cwnu.edu.cn
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