Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria 04510, Distrito Federal, México.
J Fish Biol. 2011 Oct;79(4):1029-46. doi: 10.1111/j.1095-8649.2011.03081.x. Epub 2011 Sep 9.
In viviparous organisms, pregnant females typically experience an increase in body mass and body volume. In this study, the prediction that variation in reproductive traits among populations of viviparous organisms should be related to variation among populations in body shape was tested in the Pacific molly Poecilia butleri, a viviparous fish that inhabits western Mexico and northern Central America. Variation among 10 populations in four reproductive traits was examined: brood size, individual embryo mass, total reproductive allotment and degree of maternal provisioning of nutrients to developing embryos. Variation among these populations in body shape was also examined. Significant variation among populations was observed in both brood size and reproductive allotment but not in embryo mass or degree of maternal provisioning. Significant variation among populations was also observed in body shape. After correcting for female size, however, reproductive traits and body shape were not associated among populations. This suggests that selective pressures acting on reproduction do not necessarily affect morphology and vice versa. Several factors might contribute to this unexpected lack of association between reproductive traits and morphology.
在胎生生物中，怀孕的雌性通常会经历体重和体积的增加。在这项研究中，我们检验了这样一个预测，即胎生生物种群之间的生殖特征的变异应该与种群之间的体型变异有关。研究对象是太平洋丽鱼，一种生活在墨西哥西部和中美洲北部的胎生鱼类。研究考察了 10 个种群的 4 个生殖特征的变异：窝卵数、个体胚胎质量、总生殖分配和母体向发育胚胎提供营养物质的程度。还考察了这些种群的体型变异。窝卵数和生殖分配在种群间存在显著差异，但胚胎质量和母体提供营养物质的程度在种群间没有差异。体型在种群间也存在显著差异。然而，在校正了雌鱼体型后，种群间的生殖特征和体型之间没有关联。这表明，作用于生殖的选择压力不一定会影响形态，反之亦然。有几个因素可能导致生殖特征和形态之间这种出人意料的缺乏关联。
