Kouki Jari
Department of Zoology, University of Helsinki, P. Rautatiekatu 13, SF-00100, Helsinki, Finland.
Oecologia. 1991 Sep;88(1):48-54. doi: 10.1007/BF00328402.
I followed the within-generation distribution of a chewing specialist herbivore, the water-lily beetle, on individually marked leaves of the yellow water-lily. Yellow water-lilies produced new leaves steadily throughout the growth season. Average leaf longevity was 3-4 weeks, much shorter than the developmental time of the beetle. The average egg-load of leaves was about 120. Leaf longevity was independent of egg density, but migration rate of the first instar larvae was density-dependent. Beetles occurred in every leaf, but consumed only a fraction (17%) of the available leaf area. However, this caused the leaf to lose its floating ability, so even this low rate of consumption made the leaf unavailable to herbivores. The herbivore population had to redistribute itself throughout the summer, escaping from the drowning leaves to fresh ones. No beetle could survive from egg to adult on a single leaf. The small-scale redistribution of the herbivore strongly affected the damage experienced by the host plant. In general, ability to redistribute depends on the dispersal ability of the herbivore, and thus migration ability may strongly affect the plant-herbivore interaction.
我追踪了一种咀嚼式专食性食草动物——睡莲甲虫在黄睡莲个体标记叶片上的代内分布情况。黄睡莲在整个生长季节持续长出新叶。叶片平均寿命为3至4周，远短于甲虫的发育时间。叶片上的平均卵负载量约为120个。叶片寿命与卵密度无关，但一龄幼虫的迁移率与密度有关。每片叶子上都有甲虫，但它们只消耗了可用叶面积的一小部分（17%）。然而，这导致叶片失去了漂浮能力，所以即使是这么低的消耗率也使得叶片对食草动物来说无法利用。食草动物种群在整个夏季不得不重新分布，从即将沉没的叶片转移到新叶上。没有一只甲虫能在单片叶子上从卵存活到成虫。食草动物的小规模重新分布对寄主植物遭受的损害有强烈影响。一般来说，重新分布的能力取决于食草动物的扩散能力，因此迁移能力可能会强烈影响植物与食草动物之间的相互作用。
