著者

平田 貞雄

出版者

一般社団法人 日本生態学会

雑誌

日本生態学会誌 (ISSN:00215007)

巻号頁・発行日

vol.13, no.4, pp.125-128, 1963-08-01 (Released:2017-04-08)

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The larvae of Mamestra (Barathra) brassicae (L.) were reared from hatching to pupation under solitary and crowded (10 individuals in a vial) conditions at a constant temperature of 25℃ in darkness on young leaves of the rape, Brassica napus L. Observations were made on the amount of food consumed by the larvae, the body weight of larvae and resulted pupae, and the dry weight of excreta of the 4th, 5th and 6th (final) instar larvae. The results of the observations are summarized in Table 1. Comparing with the solitary larvae, the crowded larvae consumed a larger amount of food in the 1st and 2nd instars, but less in the 4th and 5th instars. In the 3rd and 6th instars, no remarkable differences in the food consumption were observed between the solitary and crowded larvae. The total amount of food consumed in the larval stage was about equal in both densities of rearing. The crowded insects were heavier in body weight in the 1st and 2nd instars than the solitary ones, but the reversed trends were observed in the remaining instars and also in the pupal stage. The smaller ratio of the body weight to the amount of food consumed was obtained in the crowded culture in all, but the 4th instar. The dry weight of the excreta was about equal in both the solitary and crowded larvae. However, the ratio of that to the amount of food consumed was slightly smaller in the crowded larvae than in the solitary ones.