The Influence Of Light And Temperature On Certain Characters Of The Silkworm, Bombyx Mori

Abstract

Studies of the Effects of light and temperature on organisms have been receiving considerable attention for over a century, but after the discovery of various instruments by which light and temperature can be regulated they have made very rapid progress. Among the literature, some relations of metabolism or growth of organisms t!O light and temperature have been announced, but very little knowledge on the qualitative change of a certain character as influenced by the two agents. This paper follows the influence of light and temperature upon certain characters of the si lkworm, Bombyx mori, such as egg color, hibernation and larval molts. The different stages in the life-cycle of the silkworm differently respond to light and temperature, with results that the eggs of the same batch are colored either dark or light, and those either hibernating or unhibernating, and the larvae molt either three or four times. Further , new hypotheses on hibernation of the silkworm eggs and on the molting of larvae is discussed in this connection. This work was carried on at the Nagano- ken Sericultural Ex· I wish to express my thanks for the laboratory I am most deeply indebted to p~riment Station. facilities provided by Mr. Z. MrzUI, Director of the Nagano-ken Sericultural Experiment Station. Prof. Y. TAl'AKA for his stimulating guidance throughout the course of the work and for looking through the manuscript. Thanks are also due to Dr. H. ITo, Professor of the Imperial Tokyo Sericultural College, for encouragement and constructive criticism concerning Part II, and to Dr. K. WATANABE, expert of the Imperial Sericul· tural Experiment Station, for valuable advices given by him regarding the investigation of Part 1.