Studies of some factors affecting the output of silk in Bombyx mori L

Abstract

SummaryThe results obtained showed that there was a clear relationship between the ability of larvae to assimilate mulberry leaves and the resulting cocoons. The mulberry varieties, Morus alba var. rosa, M. rubra and M. alba var. Ihu, had a conspicuous effect on weights of the resulting cocoons in the three races of silkworm (Novi, Belgharia 4 and S.A. 105) studied.Results obtained also indicated that the length of the silk fibre and the weight of silk cocoons that yielded 1 kg of silk were largest when the larval diet was M. alba var. rosa or M. rubra, and were smallest when the larval diet was M. alba var. Ihu.Results also showed that the protein content determined in the resulting silk was proportional to the protein percentage in the different mulberry leaves.Feeding of larvae of the races Novi, Belgharia 4 and S.A. 105 on M. alba var. rosa and M. rubra leaves caused approximately one- to twofold increase in the fresh weights of larvae or pupae. Weights of fresh cocoons and cocoon cortex constructed by pupating larvae were largest when larval diet was M. alba var. rosa or M. rubra and were smallest when the larval diet was M. alba var. Ihu.