Historically, most North American periodical cicada (Hemiptera: Cicadidae: Magicicada spp. Davis 1925) distribution records have been mapped at county-level resolution. In recent decades, Magicicada brood distributions and especially edges have been mapped at a higher resolution, aided by the use of GIS technology after 2000. Brood VI of the 17-yr cicadas emerged in 2000 and 2017 and is the first for which detailed mapping has been completed in consecutive generations. Overlaying the records from the two generations suggests that in some places, Brood VI expanded its range slightly between 2000 and 2017, although the measured changes are close to the lower limit of detectability given the methods used. Even so, no simple alternative to range expansion easily accounts for these observations. We also bolster Alexander and Moore’s assertion that M. cassini does not occur in Brood VI.

中文翻译：

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记录周期性蝉雏六的单代范围变化（半翅目：蝉科：Magicicada spp。）

从历史上看，大多数北美周期性蝉（半翅目：蝉科：Magicicada spp. Davis 1925）的分布记录已以县级分辨率绘制。近几十年来，在 2000 年之后借助 GIS 技术的帮助下，已经以更高的分辨率绘制了魔蝉的巢分布，尤其是边缘。 17 年蝉的第六巢出现于 2000 年和 2017 年，是第一个详细绘图的蝉。连续几代完成。叠加两代人的记录表明，在某些地方，Brood VI 在 2000 年至 2017 年之间略微扩大了其范围，尽管考虑到所使用的方法，测得的变化接近可检测性的下限。即便如此，没有简单的范围扩展替代方案可以轻松解释这些观察结果。我们也支持亚历山大和摩尔关于 M.