Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet
Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet
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DOI：
10.1098/rspb.2015.1865
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发表时间：
2015-11-07
影响因子：
4.7
通讯作者：
Agrawal, Anurag A.
中科院分区：
文献类型：
--
作者：
Petschenka, Georg;Agrawal, Anurag A.
昆虫对植物毒素的抵抗力被广泛认为是对使用防御植物作为膳食资源的反应。我们测试了这一假设的马利筋蝴蝶（Danaini）已逐步演变为更高水平的抗cardenoprotein毒素的基础上，其细胞的钠-钾泵（Na+/K+-ATP酶）的氨基酸取代。利用化学，生理和毛虫生长测定不同马利筋（马利筋属）。和分离的Cardenolides，我们表明，抗性Na+/K+-ATP酶是不必要的，以科普膳食Cardenolides。相比之下，体内强心苷的螯合（作为对捕食者的防御）与Na+/K+-ATP酶抗性的三个水平相关。为了估计在没有Na+/K+-ATP酶适应的情况下心肌隔离的潜在生理负担，我们将隔离物种的血淋巴应用于隔离和非隔离物种的分离的Na+/K+-ATP酶。血淋巴强心内酯显著损害非适应性Na+/K+-ATP酶，但对螯合物种的Na+/K+-ATP酶具有系统性降低作用。我们的数据表明，对植物毒素的主要适应可能与隔离有关，而不一定是食用有毒植物的一种手段。Na+/K+-ATP酶的适应是一种潜在的机制，通过捕食刺激植物和昆虫之间的共同进化的军备竞赛。
Insect resistance to plant toxins is widely assumed to have evolved in response to using defended plants as a dietary resource. We tested this hypothesis in the milkweed butterflies (Danaini) which have progressively evolved higher levels of resistance to cardenolide toxins based on amino acid substitutions of their cellular sodium-potassium pump (Na+/K+-ATPase). Using chemical, physiological and caterpillar growth assays on diverse milkweeds (Asclepias spp.) and isolated cardenolides, we show that resistant Na+/K+-ATPases are not necessary to cope with dietary cardenolides. By contrast, sequestration of cardenolides in the body (as a defence against predators) is associated with the three levels of Na+/K+-ATPase resistance. To estimate the potential physiological burden of cardenolide sequestration without Na+/K+-ATPase adaptations, we applied haemolymph of sequestering species on isolated Na+/K+-ATPase of sequestering and non-sequestering species. Haemolymph cardenolides dramatically impair non-adapted Na+/K+-ATPase, but had systematically reduced effects on Na+/K+-ATPase of sequestering species. Our data indicate that major adaptations to plant toxins may be evolutionarily linked to sequestration, and may not necessarily be a means to eat toxic plants. Na+/K+-ATPase adaptations thus were a potential mechanism through which predators spurred the coevolutionary arms race between plants and insects.