捕食は,魚の電気信号の進化の複雑さを高める

P K Stoddard¹

¹Department of Biological Science, Florida International University, Miami 33199, USA. stoddard@fiu.edu

Nature

|July 27, 1999

まとめ

電気魚に対する捕食圧力は,予想外にも複雑な信号を好んだ. 最初,捕食者を避けるために進化したこれらの複雑な電気信号は,繁殖のための性選択によってさらに詳細に説明されました.

科学分野:

エコロジーエコロジーエコロジー
進化生物学の進化生物学について
動物の行動動物の行動

背景:

性選択理論では,動物特性の進化における制限要因として,しばしば捕食を提唱する.
経験的証拠は一般的に,捕食者が性的に選択された特徴の過剰な処理を抑制するという考えを支持しています.

研究の目的:

性選択の形成における捕食圧力の予期せぬ役割を調査する.
捕食がネオトロピカルで弱い電気を持つ魚 (ジムノティフォームス系) の信号の複雑性にどのように影響するかを調べる.

主な方法:

捕食者の検出を減らすためにジムノティフォームズのシグナル適応の分析.
捕食性の電気 (Electrophorus electricus) を用いた再生実験で,信号検出性をテストした.
生殖期における電気信号の特徴における性二形態の観察.

主要な成果:

弱い電気を持つ魚は二相信号を進化させ,そのスペクトル出力を捕食者に敏感な周波数から遠ざけた.
双相信号は,祖先の単相信号と比較して,捕食性の電気によって検出が困難であることが判明しました.
数種のヒポポミデ (Hypopomidae) の雄は,繁殖のピーク時に,信号の複雑さ,特に電気パルスの第2段階を増幅します.

結論:

捕食圧は,逆説的に,電気魚の信号の複雑さを高めることを選択しています.
暗号症 (捕食者回避) のために最初に進化したシグナル適応は,その後,性選択によって修正され,詳細に説明されました.
この研究は,捕食者主導の適応が性信号の進化を促進する新しい相互作用を明らかにしています.

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