Odum School of Ecology, University of Georgia, Athens, GA, 30602, USA.
Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA.
Ecol Lett. 2018 Nov;21(11):1670-1680. doi: 10.1111/ele.13144. Epub 2018 Aug 27.
Environmental change induces some wildlife populations to shift from migratory to resident behaviours. Newly formed resident populations could influence the health and behaviour of remaining migrants. We investigated migrant-resident interactions among monarch butterflies and consequences for life history and parasitism. Eastern North American monarchs migrate annually to Mexico, but some now breed year-round on exotic milkweed in the southern US and experience high infection prevalence of protozoan parasites. Using stable isotopes (δ H, δ C) and cardenolide profiles to estimate natal origins, we show that migrant and resident monarchs overlap during fall and spring migration. Migrants at sites with residents were 13 times more likely to have infections and three times more likely to be reproductive (outside normal breeding season) compared to other migrants. Exotic milkweed might either attract migrants that are already infected or reproductive, or alternatively, induce these states. Increased migrant-resident interactions could affect monarch parasitism, migratory success and long-term conservation.
环境变化促使一些野生动物种群从迁徙转变为定居行为。新形成的定居种群可能会影响剩余迁徙者的健康和行为。我们研究了黑脉金斑蝶的迁徙者-定居者相互作用及其对生活史和寄生的影响。东美黑脉金斑蝶每年迁徙到墨西哥，但现在有些在南美的外来乳草上全年繁殖，并经历原生动物寄生虫的高感染率。我们利用稳定同位素（δH、δC）和 cardenolide 图谱来估计出生地，结果表明，在秋季和春季迁徙期间，迁徙者和定居者黑脉金斑蝶重叠。与其他迁徙者相比，在有定居者的地点的迁徙者感染的可能性高 13 倍，繁殖的可能性（在正常繁殖季节之外）高 3 倍。外来乳草可能会吸引已经感染或繁殖的迁徙者，或者相反，诱导这些状态。增加的迁徙者-定居者相互作用可能会影响黑脉金斑蝶的寄生、迁徙成功和长期保护。
