Copying the mate choice of another conspecific by a bystanding observer is a socially mediated alternative mating strategy to independent mate choice. Because increased sperm competition is a potential cost of mate-choice copying, males should be prudent and less likely to copy the observed mate choice of other males when the latter are more sexually attractive than themselves. We tested this hypothesis using the Trinidadian guppy, Poecilia reticulata. Focal observer males were simultaneously presented with a large and a small female as potential mates, either in the presence or absence of a nearby model male. We varied the relative differences in the body length and colour ornamentation, traits that predict male sexual attractiveness and competitiveness in the guppy, of observer and model males in each of three experimental treatments: (1) observer and model males were matched for body length and colour ornamentation; (2) the model male was larger and more colourful than the observer male; (3) the model male was smaller and less colourful than the observer male. We compared the mating preferences of focal observer males in each of the latter treatments with that of focal males in a control treatment, wherein no model male (and thus no copying opportunity) was present. As predicted, focal males copied the staged apparent mate choice of a model male in all three experimental treatments, but not in the control treatment. However, contrary to our a priori hypothesis, there were no significant differences in the likelihood or strength of the copying response in observer males among the experimental treatments. Although male guppies are known to modify their mating tactics in the presence of sexual competitors, we found no evidence for an influence of the relative phenotypes of observer and model males on mate-choice copying behaviour in focal observer males.

中文翻译：

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相对性吸引力不影响雄性特立尼达孔雀鱼 Poecilia reticulata 的择偶复制

旁观者复制另一个同类的配偶选择是一种社会中介的替代性交配策略，以替代独立的配偶选择。因为精子竞争的增加是择偶复制的潜在成本，当其他雄性比自己更具性吸引力时，雄性应该谨慎并且不太可能复制观察到的其他雄性的择偶选择。我们使用特立尼达孔雀鱼 Poecilia reticulata 测试了这一假设。焦点观察者男性同时与一个大的和一个小的女性作为潜在的配偶一起出现，无论是在附近的模范男性存在还是不存在的情况下。我们改变了在三种实验处理中的每一种中，观察者和模型雄性孔雀鱼在体长和颜色装饰、预测雄性性吸引力和竞争力的特征方面的相对差异：(1) 观察者与模型雄性体长及颜色纹饰相匹配；(2) 模特男性比观察男性更大，色彩更丰富；(3) 模特男性比观察男性更小，色彩也更少。我们将后一种处理中的焦点观察者雄性的交配偏好与对照处理中的焦点雄性的交配偏好进行了比较，其中没有模型雄性（因此没有复制机会）。正如预测的那样，焦点雄性在所有三个实验处理中复制了模型雄性的分阶段表观配偶选择，但在对照处理中没有。然而，与我们的先验假设相反，在实验处理中，观察者男性的复制反应的可能性或强度没有显着差异。