Bock Brian C, Ortega Angela M, Zapata Ana María, Páez Vivian P
Instituto de Biología, Universidad de Antioquia, Medellín, Colombia.
Rev Biol Trop. 2009 Dec;57(4):1253-62. doi: 10.15517/rbt.v57i4.5462.
Intra-specific body size variation is common and often is assumed to be adaptive. Studies of body size variation among sites should include or consider environmental and ecological variables in their designs. Additionally, reciprocal transplant or common garden studies will support which variables are really contributing to the observed body size variation. This study analyzed the microgeographic body size variation in Anolis mariarum, a small lizard endemic to Antioquia, Colombia. Parameters such as body size, shape, and lepidosis variation were quantified in 217 adult A. mariarum, belonging to six populations separated by less than 80km. Results showed that significant body size variation was not related to differences among sites in mean annual temperature, but covaried with mean annual precipitation, with the largest individuals occurring in dryer sites. Mark-recapture data obtained from 115 individuals from both the wettest and dryest sites from October 2004 to April 2005 showed that growth rates were higher at the latter. Eight males from each site were captured at the end of the mark-recapture study and reared for two months under identical conditions in a common garden study. Individuals from both sites grew faster when reared in the laboratory with food provided ad libitum. Although growth rates of males from the two populations did not differ significantly in the laboratory, males from the dryest site still maintained a significantly larger asymptotic body size in their growth trajectories. Multivariate analyses also demonstrated that both males and females from the six populations differed in terms of body shape and lepidosis. However, only female body size was found to covary significantly with an environmental gradient (precipitation). A. mariarum does not conform to Bergmann's rule, but the relationship found between mean body size and asympotic growth with mean annual precipitation at these sites needs further analysis. Generally, studies of intra-specific body size variation should consider a number of additional phenotypic traits to provide stronger baseline information on the degree of overall divergence among populations, including those likely to be selectively neutral, before interpreting results of analyses on the body size differences.
种内体型变异很常见，通常被认为是适应性的。对不同地点间体型变异的研究在设计时应纳入或考虑环境和生态变量。此外， reciprocal transplant或共同园圃研究将有助于确定哪些变量真正导致了观察到的体型变异。本研究分析了哥伦比亚安蒂奥基亚特有的小型蜥蜴玛丽安安乐蜥（Anolis mariarum）的微观地理体型变异。对217只成年玛丽安安乐蜥的体型、形状和鳞片变异等参数进行了量化，这些蜥蜴分属于六个相距不到80公里的种群。结果表明，显著的体型变异与各地点年均温度差异无关，而是与年均降水量相关，体型最大的个体出现在较干燥的地点。2004年10月至2005年4月从最湿润和最干燥地点的115只个体获得的标记重捕数据表明，后者的生长速率更高。在标记重捕研究结束时，从每个地点捕获8只雄性个体，并在共同园圃研究中在相同条件下饲养两个月。当在实验室中自由提供食物饲养时，来自两个地点的个体生长都更快。尽管来自两个种群的雄性在实验室中的生长速率没有显著差异，但来自最干燥地点的雄性在其生长轨迹中仍保持显著更大的渐近体型。多变量分析还表明，六个种群的雄性和雌性在体型和鳞片方面存在差异。然而，仅发现雌性体型与环境梯度（降水量）显著相关。玛丽安安乐蜥不符合伯格曼法则，但在这些地点发现的平均体型和渐近生长与年均降水量之间的关系需要进一步分析。一般来说，种内体型变异研究在解释体型差异分析结果之前，应考虑许多其他表型特征，以提供关于种群间总体分化程度的更强有力的基线信息，包括那些可能为选择性中性的特征。
