Department of Biological Science, Kongju National University, Gongju 32588, Republic of Korea.
Department of Biological Science, Kongju National University, Gongju 32588, Republic of Korea.
Sci Total Environ. 2020 Jul 15;726:138596. doi: 10.1016/j.scitotenv.2020.138596. Epub 2020 Apr 11.
Amphibian populations are declining throughout the world, which has negatively impacted various organisms and ecosystems. The goal of this study was to obtain a better understanding of the physiological status and condition of individuals in amphibians is needed to preserve these groups. We used radiography to assess physical conditions in Hyla japonica frogs, which are widely distributed in East Asia. Bone images were examined to determine fractures and metabolic bone disease of frogs in a wild population. The bone-mineral density (BMD), stable nitrogen isotope ratio (δN), and physical conditions (body length, age, and body weight) and body compositions (fat mass and lean mass) were measured to identify changes correlating with the food-intake status. To analyze the physiological and morphological effects of predation pressure in H. japonica, we compared the BMD, food-intake status, physical conditions, body compositions and skeletal shape in H. japonica between populations with Lithobates catesbeianus (paddy fields with bullfrogs; PB) and without L. catesbeianus (no bullfrogs; NB). Only five of 101 H. japonica frogs had fractures, and no bone disease due to malnutrition was found. The food-intake status correlated with the BMD, but not to the other physical conditions and body compositions measured. Similarly, the BMD and δN of the NB group were higher than those of the PB group, but the other physical conditions and body compositions were not different. The skeletal shapes of the head and lower body were not significantly different between the two groups. Our findings revealed that the BMD can be used to determine the food-intake status and be changed in by predation pressure. We suggest using the BMD of anurans to estimate physiological changes that occur in response to the habitat or biological interactions.
两栖动物的数量在全球范围内下降，这对各种生物和生态系统产生了负面影响。本研究的目的是更好地了解两栖动物个体的生理状况和健康状况，以保护这些群体。我们使用 X 光来评估日本林蛙的身体状况，日本林蛙广泛分布于东亚。检查骨骼图像以确定野生种群中青蛙的骨折和代谢性骨病。测量骨矿物质密度（BMD）、稳定的氮同位素比值（δN）以及身体状况（体长、年龄和体重）和身体成分（体脂肪和瘦体重），以确定与食物摄入状况相关的变化。为了分析捕食压力对日本林蛙的生理和形态影响，我们比较了有牛蛙（稻田有牛蛙；PB）和无牛蛙（无牛蛙；NB）的日本林蛙种群之间的 BMD、食物摄入状况、身体状况、身体成分和骨骼形状。在 101 只日本林蛙中，只有 5 只出现骨折，没有发现因营养不良导致的骨骼疾病。食物摄入状况与 BMD 相关，但与其他测量的身体状况和身体成分无关。同样，NB 组的 BMD 和 δN 高于 PB 组，但其他身体状况和身体成分没有差异。两组的头部和下体骨骼形状没有显著差异。我们的研究结果表明，BMD 可用于确定食物摄入状况，并可因捕食压力而改变。我们建议使用无尾目动物的 BMD 来估计因栖息地或生物相互作用而发生的生理变化。
