複雑なダイナミクスが蝶の不完全な翅型収束の進化の根底にある

Complex dynamics underlie the evolution of imperfect wing pattern convergence in butterflies.

• Susan D Finkbeiner
• Adriana D Briscoe
• Sean P Mullen

抄録

しかし、適応的多様化を促進する進化のメカニズムを理解するためには、複数の生命誌段階で自然淘汰がどのように作用しているかについての詳細な知識が必要である。この仮説を検証するために、我々はコスタリカで人工的な蝶の擬態を用いた捕食研究を行った。具体的には、ルビアカエ科の宿主植物を食べない毒性のない口当たりの良いアデルファ種は、おそらく毒性のあるルビアカエを食べる種と局所的に収束した翅型を共有し、捕食を減らすことで利益を得ると予測した。これらのデータから、毒性のあるルビアカエを餌とすると考えられるAdelpha種が鳥類の捕食者から保護されていることを示す初めての証拠が得られたが、不正確な擬態パターンは熱帯地域のベイツ類の擬態には大きなコストがかかると結論づけた。

Adaptive radiation is characterized by rapid diversification that is strongly associated with ecological specialization. However, understanding the evolutionary mechanisms fueling adaptive diversification requires a detailed knowledge of how natural selection acts at multiple life-history stages. Butterflies within the genus Adelpha represent one of the largest and most diverse butterfly lineages in the Neotropics. Although Adelpha species feed on an extraordinary diversity of larval hosts, convergent evolution is widespread in this group, suggesting that selection for mimicry may contribute to adaptive divergence among species. To investigate this hypothesis, we conducted predation studies in Costa Rica using artificial butterfly facsimiles. Specifically, we predicted that nontoxic, palatable Adelpha species that do not feed on host plants in the family Rubiaceae would benefit from sharing a locally convergent wing pattern with the presumably toxic Rubiaceae-feeding species via reduced predation. Contrary to expectations, we found that the presumed mimic was attacked significantly more than its locally convergent model at a frequency paralleling attack rates on both novel and palatable prey. Although these data reveal the first evidence for protection from avian predators by the supposed toxic, Rubiaceae-feeding Adelpha species, we conclude that imprecise mimetic patterns have high costs for Batesian mimics in the tropics.

© 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.