LOCALIZATION OF HEART POISONS IN MONARCH BUTTERFLY
LOCALIZATION OF HEART POISONS IN MONARCH BUTTERFLY
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DOI：
10.1126/science.188.4183.19
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发表时间：
1975-01-01
期刊：
影响因子：
56.9
通讯作者：
GLAZIER, SC
中科院分区：
文献类型：
--
作者：
BROWER, LP;GLAZIER, SC
帝王蝶在幼虫期从乳草植物中分离出的强心苷，其催吐力有显著差异，并在身体不同部位以及两性体内有不同程度的聚集。这些化合物在翅膀中的浓度非常高，可能有助于捕食者习得的味觉排斥，也是自然种群中翅膀上有喙的Danaid蝴蝶出现频率相对较高的原因。腹部的强心苷比身体其他部位的强效要强得多。因此，幼稚、极度饥饿或健忘的鸟类捕捉并啄掉翅膀，但吃腹部，会丢弃最不呕吐的糖苷，摄取最呕吐的东西，从而再次经历呕吐。雌雄在翅膀、腹部和胸腔中的非随机分布，以及雄蜂不仅含有比雌性更低浓度的心脏糖苷，而且总体上比雌性更少呕吐的事实，被解释为这些毒物是以生理成本并入的证据。这一成本与保护免受捕食的好处相平衡，为自然种群中呕吐和非呕吐个体的出现提供了选择性基础。由于鸟类可以根据口味区分呕吐和非呕吐的君主，因此没有必要援引亲属或群体选择的理论来解释这种不受欢迎的进化。
The cardiac glycosides that monarch butterflies sequester from milkweed plants during the larval stage differ remarkably in their emetic potency and are concentrated to different degrees in the various parts of the body as well as in the two sexes. The very high concentrations of these compounds in the wings probably facilitate learned taste rejection in predators and account for the relatively high frequency of Danaid butterflies with beak-marked wings in natural populations. The cardiac glycosides in the abdomen have a much higher emetic potency than those in the rest of the body. Consequently, naive, extremely hungry, or forgetful birds which capture and peck off the wings but eat the abdomen discard the least emetic glycosides and ingest the most emetic, and thus again experience emesis. The nonrandom distribution of cardenolides in the wings, abdomen, and thorax, together with the fact that monarch males not only contain lower concentrations of cardiac glycosides than females but also contain cardenolides that are overall less emetic than those in females, is interpreted as evidence that these poisons are incorporated at a physiological cost. This cost, balanced against the benefits of protection from predation, provides a selective basis for the occurrence of both emetic and nonemetic individuals in natural populations. Since birds can discriminate emetic from nonemetic monarchs on the basis of taste, it is not necessary to invoke theories of kin or group selection to explain the evolution of this kind of unpalatability.