Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
PLoS One. 2011;6(5):e20040. doi: 10.1371/journal.pone.0020040. Epub 2011 May 13.
The study of life history variation is central to the evolutionary theory. In many ectothermic lineages, including lizards, life history traits are plastic and relate to several sources of variation including body size, which is both a factor and a life history trait likely to modulate reproductive parameters. Larger species within a lineage, for example tend to be more fecund and have larger clutch size, but clutch size may also be influenced by climate, independently of body size. Thus, the study of climatic effects on lizard fecundity is mandatory on the current scenario of global climatic change. We asked how body and clutch size have responded to climate through time in a group of tropical lizards, the Tropidurinae, and how these two variables relate to each other. We used both traditional and phylogenetic comparative methods. Body and clutch size are variable within Tropidurinae, and both traits are influenced by phylogenetic position. Across the lineage, species which evolved larger size produce more eggs and neither trait is influenced by temperature components. A climatic component of precipitation, however, relates to larger female body size, and therefore seems to exert an indirect relationship on clutch size. This effect of precipitation on body size is likely a correlate of primary production. A decrease in fecundity is expected for Tropidurinae species on continental landmasses, which are predicted to undergo a decrease in summer rainfall.
生命史变异的研究是进化理论的核心。在许多变温动物谱系中，包括蜥蜴，生命史特征是可塑的，并与包括体型在内的几个变异源有关，体型既是一个因素，也是一个可能调节繁殖参数的生命史特征。例如，同一谱系内的较大物种往往更具繁殖力，具有更大的卵窝大小，但卵窝大小也可能受到气候的影响，而与体型无关。因此，在当前全球气候变化的背景下，研究气候对蜥蜴繁殖力的影响是必要的。我们询问了在一组热带蜥蜴（Tropidurinae）中，体型和卵窝大小随时间如何对气候做出反应，以及这两个变量如何相互关联。我们使用了传统和系统发育比较方法。Tropidurinae 内部的体型和卵窝大小是可变的，这两个特征都受到系统发育位置的影响。在整个谱系中，体型较大的物种产卵更多，而且这两个特征都不受温度成分的影响。然而，降水的一个气候成分与较大的雌性体型有关，因此似乎对卵窝大小有间接关系。降水对体型的这种影响可能是初级生产力的一个相关因素。预计在夏季降雨量减少的情况下，热带蜥蜴物种的繁殖力将会下降。
