School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA.
Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA.
Commun Biol. 2019 Feb 18;2:68. doi: 10.1038/s42003-019-0303-z. eCollection 2019.
Mimics should not exist without their models, yet often they do. In the system involving queen and viceroy butterflies, the viceroy is both mimic and co-model depending on the local abundance of the model, the queen. Here, we integrate population surveys, chemical analyses, and predator behavior assays to demonstrate how mimics may persist in locations with low-model abundance. As the queen becomes less locally abundant, the viceroy becomes more chemically defended and unpalatable to predators. However, the observed changes in viceroy chemical defense and palatability are not attributable to differing host plant chemical defense profiles. Our results suggest that mimetic viceroy populations are maintained at localities of low-model abundance through an increase in their toxicity. Sharing the burden of predator education in some places but not others may also lower the fitness cost of warning signals thereby supporting the origin and maintenance of aposematism.
拟态者若无其模型便无法存在，但它们常常存在。在涉及帝王蝶及其副王蝶的系统中，副王蝶既是拟态者，也是同型模拟者，具体取决于模型（即帝王蝶）在当地的丰富度。在这里，我们综合了种群调查、化学分析和捕食者行为分析，以证明拟态者如何在模型（即帝王蝶）数量较少的地方得以生存。随着帝王蝶在当地变得越来越稀少，副王蝶的化学防御能力会增强，对捕食者的适口性也会降低。然而，观察到的副王蝶化学防御和适口性的变化并不能归因于不同的寄主植物的化学防御特征。我们的研究结果表明，通过增加毒性，具有拟态的副王蝶种群可以在模型（即帝王蝶）数量较少的地方得以维持。在某些地方分担捕食者教育的负担，而在其他地方则不承担，这也可能降低警戒信号的适应代价，从而支持警戒色的起源和维持。
