マツノキハバチに関する生態学的研究 : II.集団サイズと死亡率・死亡要因の関係について

概要

論文の詳細を見る
The survival rate and the mortality causes of Neodiprion sertifer were investigated from the egg stage to the fourth instar at two census areas (Campus Forest B and Ohshiba), Nagano Prefecture in 1976 and 1977. High mortality due to the predation of spiders occurred in first-instar larvae at Campus Forest B, where the population density was comparatively low. In contrast, many larvae in the third instar died of the disease at Ohshiba, where outbreaks of N. sertifer had frequently occurred since 1975. The rate of hatchability of eggs at Ohshiba was 10% lower than that at Campus Forest B, but there was no significant relationship between the size of the egg clusters and the rate of hatchability. The mortality of the first instar larvae became higher with the decrease in the size of colony at both census areas in 1976. At Ohshiba in 1976,the mortality due to the disease occurred in earlier stages in small colonies than in the large ones, and all larvae of the colonies with less than 50 individuals died of the disease in the third instar stage. It was revealed by key-factor analysis that predation by spiders in the group in the first instar at Campus Forest B and the disease in the group in the third instar at Ohshiba were the main factors which gave rise to a difference in the mortality rate among the colonies, although these factors changed with the increase in the size of the colonies.
日本応用動物昆虫学会の論文
1981-05-25