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“2.GWD的原题 一个物种有生命周期的,不随环境呀,捕食者呀什么的改变,为了研究这个生命周期的原因,科学家做了些实验,后来提出了个假设,是因为一种病毒。。。。童鞋们想起来了吧。晚些我找到这个阅读,我再发出来哈“
应该是这篇吧?GWD-TN-13 T-9-Q20-Q23:GWD-13-34~37 A small number of the forest species of lepidoptera (moths and butterflies, which exist as caterpillars during most of their life cycle) exhibit regularly recurring patterns of population growth and decline—such fluctuations in population are known as population cycles. Although many different variables influence population levels, a regular pattern such as a population cycle seems to imply a dominant, driving force. Identification of that driving force, however, has proved surprisingly elusive despite considerable research. The common approach of studying causes of population cycles by measuring the mortality caused by different agents, such as predatory birds or parasites, has been unproductive in the case of lepidoptera. Moreover, population ecologists’ attempts to alter cycles by changing the caterpillars’ habitat and by reducing caterpillar (25) populations have not succeeded. In short, the evidence implies that these insect populations, if not self-regulating, may at least be regulated by an agent more intimately connected with the insect than are predatory birds or parasites. (30) ........ |
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