Advances in understanding the long-term population decline of monarch butterflies
Advances in understanding the long-term population decline of monarch butterflies
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DOI：
10.1073/pnas.1903409116
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发表时间：
2019-03
期刊：
影响因子：
--
通讯作者：
A. Agrawal
中科院分区：
文献类型：
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作者：
A. Agrawal
帝王蝶是大自然的象征：形态壮观，以其深不可测的年度迁徙而闻名，并且经常在我们的后院访问（图1）。难怪它们是无脊椎动物中的宠儿。现在引起我们注意的是过去二十年来帝王蝶种群数量的急剧下降。生物多样性的减少，当前大规模灭绝的一部分，对我们来说似乎很抽象北极熊漂浮在北极的冰山上，或者热带雨林的砍伐和燃烧。但是，帝王蝶的减少就像一个“沉默的春天”，生物学家和普通观察者都注意到最近许多夏天失踪的蝴蝶，特别是在美国东北部和中西部。发表在PNAS上的两项新研究增加了新的分析，相当新的数据和新颖的方法来解决君主之谜（1，2）。Fig. 1.（上）北美东部帝王蝶的年度迁徙周期。第1代发生在以德克萨斯州为中心的美国墨西哥湾沿岸各州（3月至4月），第2至4代发生在东北部和中西部（5月至9月）。第四代迁徙的生活8个月，包括越冬在墨西哥和返回墨西哥湾沿岸各州，并不依赖乳草之间的9月和2月。（下图）墨西哥中部高地帝王蝶的数量下降（第4代，估计在越冬期间）（数据由世界野生动物基金会墨西哥收集）。圈出的年份是Saunders等人研究的年份（1）。尽管至少从1977年（在公民科学家与加拿大生物学家弗雷德和诺拉·厄克特合作发现它们的越冬地一年后）就有人提出了对帝王蝶保护的担忧，但帝王蝶在1999年和1999年成为公众关注的两个关键时刻[1][2] 1电子邮件：agrawal{at} cornell.edu。[1]：#xref-corresp-1-1
Monarch butterflies are an icon of nature: spectacular in form, known for their unfathomable annual migration, and frequent visitors in our backyards (Fig. 1). It is no wonder they are a darling among invertebrates. And what has now captured our attention is the striking and precipitous decline of monarch populations over the past two decades. So much of the decline in biodiversity, part of the current mass extinction, seems abstract to us—the polar bear floating on an iceberg in the arctic, or the slash and burn of tropical rain forests. But the decline of monarch butterflies has been observed like a “silent spring,” with biologists and casual observers alike noticing the missing butterflies from so many of our recent summers, especially in the northeastern and midwestern United States. Two new studies published in PNAS add fresh analyses, considerably new data, and novel approaches to tackle the monarch mystery (1, 2). Fig. 1. ( Top ) The annual migratory cycle of eastern North American monarch butterflies. Generation 1 occurs in the US Gulf Coast states centered on Texas (March–April), and generations 2 to 4 occur in the Northeast and Midwest (May–September). The fourth migratory generation lives for 8 mo, including overwintering in Mexico and returning to the Gulf Coast states, and does not rely on milkweed between September and February. ( Bottom ) The population decline of monarch butterflies in the highlands of Central Mexico (generation 4, estimated during overwintering) (data collected by World Wildlife Fund Mexico). The circled years are those investigated by Saunders et al. (1). Although concerns about monarch conservation have been voiced at least since 1977 (a year after their overwintering grounds were discovered by citizen scientists, in collaboration with Canadian biologists Fred and Nora Urquhart), two key moments in the monarch’s rise to public prominence came in 1999 and … [↵][1]1Email: agrawal{at}cornell.edu. [1]: #xref-corresp-1-1