Not all colors are equal: predation and color polytypism in the aposematic poison frog Oophaga pumilio
Not all colors are equal: predation and color polytypism in the aposematic poison frog Oophaga pumilio
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DOI：
10.1007/s10682-012-9605-z
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发表时间：
2013-09-01
影响因子：
1.9
通讯作者：
Donnelly, Maureen A.
中科院分区：
文献类型：
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作者：
Hegna, Robert H.;Saporito, Ralph A.;Donnelly, Maureen A.
据预测，非寄生生物不会表现出高水平的警告信号多样性，因为预计它们将处于稳定的选择之下，以降低对捕食者进行不适口性教育的成本。然而，如果警告信号代表了对当地捕食者的适应，那么警告信号(多型性)的系统性变化是可以预期的。草莓毒蛙(Oophaga Pumilio)在哥斯达黎加和巴拿马的整个大陆分布都是红色的，但在巴拿马的博卡斯德尔托罗群岛显示出高度的警告信号多样性。颜色和斑点图案都在多型性意义上有所不同。性别选择有助于维持多型性，但很少有人研究捕食的潜在影响。我们使用未发现斑点的美洲斑潜蝇模型来确定捕食是否有助于解释巴拿马博卡斯德尔托罗群岛Isla Coln上的颜色多型性。我们测试了红色大陆变种、绿色/黄色Isla Coln变种和棕色对照之间的攻击率是否存在差异。我们发现，青蛙的颜色显著预示着被攻击。当地的绿色Isla Coln车型受到的攻击比外国红色或棕色车型更多。红色和棕色对照模型在攻击率上没有差异。我们的结果表明，红色大陆变种具有更有效的警告信号，即使它不是本地变种。诚实的信号表明不好吃、新恐惧症，以及当地捕食者使用搜索图像是潜在的解释。棕色模型与其他本地毒蛙的相似性可能解释了与以前的工作相比，攻击比率较低的原因。与哥斯达黎加大陆相比，伊拉科尔岛的捕食率较低，这支持了这样的假设，即博卡斯德尔-托罗群岛较少的总体捕食可能通过放松对缺失特征的选择来促进那里的奥马利奥警报信号的多样性。
Aposematic organisms are not predicted to show high levels of warning signal diversity because they are expected to be under stabilizing selection to decrease costs of 'educating' predators about their unpalatability. However, systematic changes in warning signals (polytypism) can be expected if they represent adaptations to local predators. The aposematic strawberry poison frog (Oophaga pumilio) is red throughout its mainland distribution in Costa Rica and Panama, but displays high levels of warning signal diversity in the Bocas del Toro Archipelago of Panama. Both coloration and spot pattern vary in a polytypic sense. Sexual selection contributes to maintaining the polytypism, but little work has investigated the potential influence of predation. We used unspotted models of O. pumilio to determine if predation might help explain the color polytypism on Isla Coln in the Bocas del Toro Archipelago of Panama. We tested whether attack rates differed among the red mainland morph, green/yellow Isla Coln morph, and the brown control. We found that frog color significantly predicted being attacked. The local green Isla Coln models were attacked more than foreign red or brown models. No difference in attack rate existed between red and brown control models. Our results suggest that the red mainland morph possesses a more effective warning signal, even when it is not the local morph. Honest signaling of unpalatability, neophobia, and the use of search images by local predators are potential explanations. Similarity of the brown model to other local poison frogs might explain the lower attack rate compared to previous work. The attack rate was lower on Isla Coln compared to mainland Costa Rica, which supports the hypothesis that less overall predation in the Bocas del Toro Archipelago may contribute to the overall warning signal diversity in O. pumilio there by relaxing selection for aposematic traits.