Habitat loss in the summer breeding range contributes to eastern North American monarch (Lepidoptera: Nymphalidae) population decline. Habitat restoration efforts include increasing native prairie plants for adult forage and milkweed (Asclepias spp.) for oviposition and larval development. As the monarch is a vagile species, habitat establishment at a grain that matches the monarch perceptual range will facilitate efficient movement, decrease fitness costs of dispersal, and increase oviposition. We released 188 experimental monarch females 5, 25, 50, and 75 m downwind from potted milkweed and blooming forbs in 4–32 ha sod fields. Perceptual range was estimated from monarchs that flew towards and landed on the milkweed and forbs. Flight patterns of 49 non-experimental monarchs that landed on the resources were also observed. In our experimental, resource-devoid setting, wind-facilitated movement occurred most frequently. Monarchs performed direct displacement as evidenced by shallow turn angles and similarity of Euclidian and total distances traveled. We hypothesize similar monarch flight behavior when traveling over other resource-devoid areas, such as crop fields. Although the majority of experimental monarchs flew downwind, eight experimental and 49 non-experimental monarchs were observed flying upwind toward, and landing on, the potted resources from distances ranging from 3 to 125 m (mean = 30.98 m, median = 25 m, mode = 25 m). A conservative estimate of the perceptual range is 125 m, as longer distances cannot be precluded; however, the majority of observations were ≤50 m. Our findings suggest establishing habitat patches ~ 50 m apart would create functional connectivity across fragmented agricultural landscapes.

中文翻译：

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估计雌性帝王蝶 (Danaus plexippus) 对盆栽植物普通乳草 (Asclepias syriaca) 和开花花蜜资源的感知范围

夏季繁殖区的栖息地丧失导致北美东部君主（鳞翅目：蛱蝶科）种群数量下降。栖息地恢复工作包括增加用于成年草料的原生草原植物和用于产卵和幼虫发育的乳草（Asclepias spp.）。由于君主是一种灵活的物种，在与君主感知范围相匹配的谷物上建立栖息地将促进有效的运动，降低分散的适应性成本，并增加产卵量。我们在 4-32 公顷草皮田中从盆栽马利筋和开花的草丛中释放了 188 只实验性君主雌性，分别为 5、25、50 和 75 m。感知范围是根据飞向并降落在乳草和杂草上的君主估计的。还观察了降落在资源上的49个非实验君主的飞行模式。在我们的实验中，资源匮乏环境下，风助运动发生频率最高。君主进行直接位移，如浅转角和欧几里得的相似性和总行驶距离所证明的那样。我们假设在其他资源匮乏的地区（例如农田）旅行时类似的君主飞行行为。尽管大多数实验帝王蝶都顺风飞行，但观察到 8 只实验帝王蝶和 49 只非实验帝王蝶从 3 到 125 m 的距离（平均值 = 30.98 m，中位数 = 25 m，众数）逆风飞行并降落在盆栽资源上= 25 米）。感知范围的保守估计为 125 m，因为不能排除更长的距离；然而，大多数观测值≤50 m。