School of Biology and Ecology, University of Maine, 5751 Murray Hall, Orono, Maine 04469, USA.
Evolution. 2010 Jun;64(6):1802-15. doi: 10.1111/j.1558-5646.2010.00945.x. Epub 2010 Jan 11.
We conducted 10 mark-recapture experiments in natural populations of Trinidadian guppies to test hypotheses concerning the role of viability selection in geographic patterns of male color variation. Previous work has reported that male guppies are more colorful in low-predation sites than in high-predation sites. This pattern of phenotypic variation has been theorized to reflect differences in the balance between natural (viability) selection that disfavors bright male color (owing to predation) and sexual selection that favors bright color (owing to female choice). Our results support the prediction that male color is disfavored by viability selection in both predation regimes. However, it does not support the prediction that viability selection against male color is weaker in low-predation experiments. Instead, some of the most intense bouts of selection against color occurred in low-predation experiments. Our results illustrate considerable spatiotemporal variation in selection among experiments, but such variation was not generally correlated with local patterns of color diversity. More complex selective interactions, possibly including the indirect effects of predators on variation in mating behavior, as well as other environmental factors, might be required to more fully explain patterns of secondary sexual trait variation in this system.
我们在特立尼达的鳉鱼自然种群中进行了 10 次标记-重捕实验，以检验关于生存力选择在雄性颜色变化的地理模式中的作用的假设。先前的研究报告称，在低捕食压力的地点，雄性鳉鱼比在高捕食压力的地点颜色更为鲜艳。这种表型变异模式被认为反映了自然（生存力）选择和性选择之间平衡的差异，前者不利于鲜艳的雄性颜色（由于捕食），后者有利于鲜艳的颜色（由于雌性选择）。我们的结果支持这样的预测，即在两种捕食压力下，雄性颜色都受到生存力选择的不利影响。然而，它并不支持这样的预测，即生存力选择对雄性颜色的影响在低捕食压力的实验中较弱。相反，在低捕食压力的实验中，一些最强烈的颜色选择发生了。我们的结果说明了在实验中选择的相当大的时空变化，但这种变化通常与颜色多样性的局部模式无关。可能需要更复杂的选择性相互作用，包括捕食者对交配行为变异的间接影响，以及其他环境因素，以更充分地解释这个系统中次要性特征变异的模式。
