Population cycles are characteristic of small mammals, and they sometimes appear to be brought about by predators.

数量的周期循环是小型哺乳动物的特征，它们有时似乎是由捕食者造成的。

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Remarkably, despite significant differences in habitat and behavior, many species of lepidoptera have population cycles of similar length, between eight and eleven years.

值得注意的是，尽管鳞翅目昆虫在栖息地和行为上存在显著差异，但许多种类的鳞翅目昆虫的种群周期相似，在8到11年之间。

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If their population is tracked through time, it will be seen to be particularly unstable—soaring and plummeting in irregular cycles.

如果对它们的数量进行时间记录，就会发现它是很不稳定的——以不规则的周期急剧上升下降。

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Furthermore, this is just the impact of the aging population on business cycles, there is also the very serious problem of how it will affect our finances.

FORBES: Does An Aging Population Hurt The Economy?