Studies on the Population of teh Apple Leaf Miner Phyllonorycter ringoniella MATSUMURA (Lepidoptera : Lithocolletidae) : III. Some Analyses of the Mortality Factors Operating upon the Population

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Based on teh life table studies for the apple leaf miner, Phyllonoructer ringoniella MATSUMURA, five mortality factors which played important roles in reduction larvae were chosen and the characteristics of their operations were analyzed on the following two ponts; (1) changes of the mortality rates in accordance with the changes of the numbers of the living larvae per leaf and (2) frequency distribution of deaths per leaf in comparison with the binomial series. Mortality during the sap feeding stage was dependent on density per leaf. This was mainly due to the cannbalism. Operations of other factors were independent of the numbers of larvae per leaf. Distributions of deaths due to unknown factors operating upon the sap feeding and tissue feeding stages and those of the parasitism of Sympiesis sp. were nearly fitted to the binomia series, which suggested that reductions of larvae due to these factors occured independently of each ather in a given leaf. Distributions of parasitisms of H. testaceipes and those of deaths due to cannibalism did not follow the binomial series.