Department of Biological Sciences, Boston University, Boston, MA 02215, USA
Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637, USA.
Proc Biol Sci. 2018 Apr 11;285(1876). doi: 10.1098/rspb.2017.2786.
Despite more than a century of biological research on the evolution and maintenance of mimetic signals, the relative frequencies of models and mimics necessary to establish and maintain Batesian mimicry in natural populations remain understudied. Here we investigate the frequency-dependent dynamics of imperfect Batesian mimicry, using predation experiments involving artificial butterfly models. We use two geographically distinct populations of butterflies that vary in their relative frequencies of a putatively defended model () and Batesian mimic (). We found that in Costa Rica, where both species share similar abundances, Batesian mimicry breaks down, and predators more readily attack artificial butterfly models of the presumed mimic, By contrast, in Ecuador, where (model) is significantly more abundant than (mimic), both species are equally protected from predation. Our results provide compelling experimental evidence that imperfect Batesian mimicry is frequency-dependent on the relative abundance of models and mimics in natural populations, and contribute to the growing body of evidence that complex dynamics, such as seasonality or the availability of alternative prey, influence the evolution of mimetic traits.
尽管对拟态信号的进化和维持进行了一个多世纪的生物学研究，但在自然种群中建立和维持贝氏拟态所需的模型和拟态的相对频率仍研究不足。在这里，我们使用涉及人工蝴蝶模型的捕食实验来研究不完全贝氏拟态的频率依赖性动态。我们使用了两个在相对频率上存在差异的蝴蝶地理种群，即一种假定受保护的模型（）和一种贝氏拟态（）。我们发现，在哥斯达黎加，这两个物种的数量相似，贝氏拟态瓦解，捕食者更容易攻击假定拟态的人工蝴蝶模型。相比之下，在厄瓜多尔， （模型）的数量明显多于 （拟态），两种蝴蝶都同样受到捕食的保护。我们的研究结果提供了令人信服的实验证据，表明不完全贝氏拟态是依赖于自然种群中模型和拟态的相对丰度的，这也证明了复杂的动态（如季节性或替代猎物的可用性）会影响拟态特征的进化。
