A free lunch? No cost for acquiring defensive plant pyrrolizidine alkaloids in a specialist arctiid moth (Utetheisa ornatrix)
A free lunch? No cost for acquiring defensive plant pyrrolizidine alkaloids in a specialist arctiid moth (Utetheisa ornatrix)
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DOI：
10.1111/mec.12086
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发表时间：
2012-12-01
影响因子：
4.9
通讯作者：
Futuyma, Douglas J.
中科院分区：
文献类型：
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作者：
Cogni, Rodrigo;Trigo, Jose R.;Futuyma, Douglas J.
许多食草昆虫从它们的寄主植物中隔离防御性化学物质。我们测试了封存健身成本在专业蛾Utetheisa ornatrix（鳞翅目：Artiidae）。我们在人工饲料中添加不同浓度的吡咯里西啶生物碱（PAs）。所有的幼虫和成人健身组件测量，只有发展时间是负面影响PA浓度。这些结果在紧张的实验室条件下重复。另一方面，螯合的PA的量大大增加与饮食PA浓度。如果所有的个体都表达了解毒和螯合的生化机制，那么没有可检测到的负面影响并不一定意味着没有成本。因此，我们使用qPCR来显示用于使PA解毒的基因吡咯烷生物碱N-加氧酶（pno）的表达在我们的最高PA处理中增加了41倍。然而，健身组件的影响很小，或根本没有，这表明在这个物种中的封存不会产生很大的成本。明显缺乏成本对我们理解生态相互作用的进化具有重要意义;例如，它意味着专业食草动物的选择可能会降低植物种群中某些化学防御的水平。
Many herbivorous insects sequester defensive chemicals from their host plants. We tested sequestration fitness costs in the specialist moth Utetheisa ornatrix (Lepidoptera: Arctiidae). We added pyrrolizidine alkaloids (PAs) to an artificial diet at different concentrations. Of all the larval and adult fitness components measured, only development time was negatively affected by PA concentration. These results were repeated under stressful laboratory conditions. On the other hand, the amount of PAs sequestered greatly increased with the diet PA concentration. Absence of a detectable negative effect does not necessarily imply a lack of costs if all individuals express the biochemical machinery of detoxification and sequestration constitutively. Therefore, we used qPCR to show that expression of the gene used to detoxify PAs, pyrrolizidine-alkaloid-N-oxygenase (pno), increased 41-fold in our highest PA treatment. Nevertheless, fitness components were affected only slightly or not at all, suggesting that sequestration in this species does not incur a strong cost. The apparent lack of costs has important implications for our understanding of the evolution of ecological interactions; for example, it implies that selection by specialist herbivores may decrease the levels of certain chemical defences in plant populations.