Department of Entomology, University of Kentucky, Lexington, KY, USA.
Sci Rep. 2018 Aug 14;8(1):12139. doi: 10.1038/s41598-018-30731-z.
The eastern North American migratory population of monarch butterflies (Danaus plexippus) is in serious decline. Habitat restoration, including adding millions of host plants to compensate for loss of milkweed in US cropland, is a key part of the international conservation strategy to return this iconic butterfly to sustainable status. We report here that Popillia japonica, a polyphagous, invasive beetle, aggregates and feeds on flowers of Asclepias syriaca, the monarch's most important larval food plant, reducing fruiting and seed set by >90% and extensively damaging milkweed umbels in the field. The beetle's ongoing incursion into the monarch's key breeding grounds in the US Midwest is likely to limit pollination and outcrossing of wild and planted milkweeds, reducing their capacity to colonize new areas via seeds. Popillia japonica represents a previously undocumented threat to milkweeds that should be considered in models for monarch habitat restoration.
东方北美迁徙的黑脉金斑蝶（Danaus plexippus）种群数量正在严重减少。栖息地恢复，包括在美国农田种植数百万株寄主植物，以弥补马利筋的损失，是使这种标志性蝴蝶恢复可持续生存状态的国际保护策略的关键部分。我们在这里报告，日本猿叶虫（Popillia japonica）是一种多食性、入侵性的甲虫，聚集并取食 Asclepias syriaca 的花朵，这是黑脉金斑蝶最重要的幼虫食物植物，导致果实和种子形成减少>90%，并在田间广泛破坏马利筋伞形花序。这种甲虫持续入侵黑脉金斑蝶在美国中西部的主要繁殖地，可能会限制野生和种植马利筋的授粉和异交，降低它们通过种子在新地区定居的能力。日本猿叶虫对马利筋构成了以前未记录的威胁，在黑脉金斑蝶栖息地恢复模型中应加以考虑。
