Ortega Jesús, López Pilar, Martín José
Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales, C.S.I.C, José Gutiérrez Abascal 2, 28006, Madrid, Spain,
Oecologia. 2015 Feb;177(2):357-66. doi: 10.1007/s00442-014-3185-2. Epub 2014 Dec 18.
The interplay between ecological conditions and life histories has been widely acknowledged in vertebrates, particularly in lizards. Environmental conditions may exert different selective pressures and produce divergent phenotypes even in geographically and genetically close populations. The Iberian wall lizard constitutes a perfect model organism as it is considered a species complex with a complicated evolutionary history. Here, we focus on two proximate populations in which we examined adult morphology and reproductive investment of wild-caught lizards along a 500-m altitudinal gradient with contrasting environmental conditions, where adults show marked morphological differences in spite of being closely related. Also, we performed a common garden experiment to examine embryonic and hatchling growth. We focused on reproductive investment per clutch, incubation time, egg size, morphology and growth rate of hatchlings. Results showed clutch size differences between populations that were independent of the larger body size of highland females. However, there were no egg morphological differences between populations, except for egg width, and this difference disappeared after controlling for female body size. Hatchling lizards from both populations did not differ in morphology. Moreover, we did not observe differences between populations or sexes in hatchling growth. Overall, we provide evidence that the differences in adult body size and clutch size are not driven by size at hatching which is not contributed to by egg size, nor are intrinsic hatchling growth rates associated with the environmental conditions experienced in our common garden experiment, suggesting that adult phenotypes are not the result of intrinsic differences between populations.
生态条件与生活史之间的相互作用在脊椎动物中已得到广泛认可，尤其是在蜥蜴中。即使在地理和基因上相近的种群中，环境条件也可能施加不同的选择压力并产生不同的表型。伊比利亚壁蜥是一种完美的模式生物，因为它被认为是一个具有复杂进化历史的物种复合体。在这里，我们聚焦于两个相邻种群，沿着500米的海拔梯度，在环境条件截然不同的情况下，研究了野生捕获蜥蜴的成体形态和繁殖投入，尽管它们亲缘关系很近，但成体仍表现出明显的形态差异。此外，我们进行了一项共同花园实验来研究胚胎和幼体的生长。我们关注每窝的繁殖投入、孵化时间、卵的大小、形态以及幼体的生长速度。结果显示，种群间窝卵数存在差异，且与高地雌性较大的体型无关。然而，除了卵宽之外，种群间卵的形态没有差异，并且在控制了雌性体型后，这种差异消失了。两个种群的幼体蜥蜴在形态上没有差异。此外，我们没有观察到种群或性别之间在幼体生长方面的差异。总体而言，我们提供的证据表明，成体体型和窝卵数的差异并非由孵化时的大小驱动，卵大小对此并无影响，而且幼体的内在生长速度也与我们共同花园实验中所经历的环境条件无关，这表明成体表型并非种群间内在差异的结果。
