マイマイガの低密度な個体群の個体数と分布部様式の1世代内における変化

概要

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In 1976,an occurence of the low density population of Lymantria dispar was observed in the yard of Kansai Branch, Gov. For. Expt. Sta., Kyoto. The survey on this population was carried out in 4 plots. More than 80% of the larvae immigrated in 10 days from the end of April to early May. The densities of the immigrants in the plots distributed from 0.2 per tree of 1.2m height to 11.0. Almost all of the larvae in the higher density plots were exterminated by birds (Passer montanus) and wasps (Polistes jadwigae). Although 73% of the larvae were parasitized by Apanteles liparidis, the parasites were also devoured with their hosts before leaving from the hosts. On the other hand, the larvae in the low density plot were hardly captured by the predators. Therefore, the mortalities were density-dependent among the plots of different larval density. The population was in fairly discrete clumps, and the distribution pattern of the larvae in a plot was contagious. In the low density plot, a small number of the larvae were missed every day without any conspicuous mortality factors except spiders, and the mortality was inversely density-dependent.
日本森林学会の論文
1977-11-25