Data condition dependence in biosynthesized chemical defenses of an aposematic and mimetic Heliconius butterfly

Aposematic animals advertise their toxicity or unpalatability with bright warning coloration. However, acquiring and maintaining chemical defenses can be energetically costly, and consequent associations with other important traits could shape chemical defense evolution. Here, we have tested whether chemical defenses are involved in energetic trade-offs with other traits, or whether the levels of chemical defenses are condition dependent, by studying associations between biosynthesized cyanogenic toxicity and a suite of key life-history and fitness traits in a Heliconius butterfly under a controlled laboratory setting. Heliconius butterflies are well known for the diversity of their warning color patterns and widespread mimicry, and can both sequester the cyanogenic glucosides of their Passiflora host plants and biosynthesize these toxins de novo. We find energetically costly life-history traits to be either unassociated or to show a general positive association with biosynthesized cyan...

警戒色动物（Aposematic animals）通过鲜艳的警戒色宣示自身的毒性或不可食性。然而，获取与维持化学防御的能量代价高昂，由此与其他重要性状形成的关联可能塑造化学防御的进化轨迹。本研究在受控实验室环境下，通过分析Heliconius蝴蝶体内生物合成的氰化物毒性与一系列关键生活史及适合度性状之间的关联，验证了化学防御是否与其他性状存在能量权衡关系，或是其水平是否具有条件依赖性。Heliconius蝴蝶因警戒色模式的多样性及广泛的拟态现象而广为人知，既能从西番莲属（Passiflora）宿主植物中螯合氰苷（cyanogenic glucosides），也能从头合成这些毒素。我们发现，能量消耗较大的生活史性状与生物合成的氰化物毒性要么无关联，要么呈现出普遍的正相关关系...