Department of Ecology & Evolution, The University of Chicago, Chicago, IL 60637
Department of Ecology & Evolution, The University of Chicago, Chicago, IL 60637.
Proc Natl Acad Sci U S A. 2019 Jul 16;116(29):14671-14676. doi: 10.1073/pnas.1904690116. Epub 2019 Jun 24.
The annual migration of the monarch butterfly is in peril. In an effort to aid population recovery, monarch enthusiasts across North America participate in a variety of conservation efforts, including captive rearing and release of monarch butterflies throughout the summer and autumn. However, the impact of captive breeding on monarchs remains an open question. Here, we show that captive breeding, both commercially and by summertime hobbyists, causes migratory behavior to be lost. Monarchs acquired commercially failed to orient south when reared outdoors in the autumn, unlike wild-caught North American monarchs, yet they did enter reproductive diapause. The commercial population was genetically highly divergent from wild-caught North American monarchs and had rounder forewings, similar to monarchs from nonmigratory populations. Furthermore, rearing wild-caught monarchs in an indoor environment mimicking natural migration-inducing conditions failed to elicit southward flight orientation. In fact, merely eclosing indoors after an otherwise complete lifecycle outdoors was enough to disrupt southern orientation. Our results provide a window into the complexity-and remarkable fragility-of migration.
黑脉金斑蝶的年度迁徙正面临威胁。为了帮助其种群恢复，北美的蝴蝶爱好者们参与了各种保护工作，包括在夏季和秋季对黑脉金斑蝶进行人工饲养和放归。然而，人工饲养对黑脉金斑蝶的影响仍是一个悬而未决的问题。在这里，我们发现人工饲养（包括商业性饲养和夏季业余爱好者的饲养）会导致黑脉金斑蝶失去迁徙行为。与野外捕获的北美黑脉金斑蝶不同，在秋季户外饲养的商业性饲养的黑脉金斑蝶无法向南定向，但它们确实进入了生殖滞育期。商业性饲养的黑脉金斑蝶在遗传上与野外捕获的北美黑脉金斑蝶高度不同，而且前翅更圆，类似于非迁徙种群的黑脉金斑蝶。此外，在室内环境中饲养野外捕获的黑脉金斑蝶，模拟自然诱导迁徙的条件，也无法引起其向南飞行的定向。事实上，仅仅在户外完成整个生命周期后在室内羽化就足以破坏其向南的定向。我们的研究结果提供了一个了解迁徙复杂性和惊人脆弱性的窗口。
