Lu Hong-Liang, Xu Chun-Xia, Jin Yuan-Ting, Hero Jean-Marc, Du Wei-Guo
Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration School of Life and Environmental Sciences Hangzhou Normal University Hangzhou China.
Key Laboratory of Animal Ecology and Conservation Biology Institute of Zoology Chinese Academy of Sciences Beijing China.
Ecol Evol. 2017 Dec 3;8(1):645-654. doi: 10.1002/ece3.3686. eCollection 2018 Jan.
Body size is directly linked to key life history traits such as growth, fecundity, and survivorship. Identifying the causes of body size variation is a critical task in ecological and evolutionary research. Body size variation along altitudinal gradients has received considerable attention; however, the underlying mechanisms are poorly understood. Here, we compared the growth rate and age structure of toad-headed lizards () from two populations found at different elevations in the Qinghai-Tibetan Plateau. We used mark-recapture and skeletochronological analysis to identify the potential proximate causes of altitudinal variation in body size. Lizards from the high-elevation site had higher growth rates and attained slightly larger adult body sizes than lizards from the low-elevation site. However, newborns produced by high-elevation females were smaller than those by low-elevation females. Von Bertalanffy growth estimates predicted high-elevation individuals would reach sexual maturity at an earlier age and have a lower mean age than low-elevation individuals. Relatively lower mean age for the high-elevation population was confirmed using the skeletochronological analysis. These results support the prediction that a larger adult body size of high-elevation results from higher growth rates, associated with higher resource availability.
体型与生长、繁殖力和存活率等关键生活史特征直接相关。确定体型变化的原因是生态和进化研究中的一项关键任务。沿海拔梯度的体型变化已受到相当多的关注；然而，其潜在机制仍知之甚少。在这里，我们比较了青藏高原不同海拔处两个种群的沙蜥的生长速率和年龄结构。我们使用标记重捕法和骨骼年代学分析来确定体型海拔变化的潜在直接原因。来自高海拔地点的蜥蜴比来自低海拔地点的蜥蜴具有更高的生长速率，成年体型也略大。然而，高海拔雌性产生的新生幼体比低海拔雌性的新生幼体小。冯·贝塔朗菲生长估计预测，高海拔个体将在更早的年龄达到性成熟，平均年龄低于低海拔个体。使用骨骼年代学分析证实了高海拔种群的平均年龄相对较低。这些结果支持了这样的预测，即高海拔沙蜥较大的成年体型是由较高的生长速率导致的，而较高的生长速率与更高的资源可用性相关。
