Ito, Yosiaki2017-06-012017-06-01http://hdl.handle.net/2097/35706In recent years there have been many experimental studies on the multiplication of insects, which has led to the understanding that under specific conditions the growth of an insect population follows the logistic curve as proposed by Verhurst and Pearl. In addition, many mechanisms for this phenomenon have been posited. According to Uchida (1949), insect population growth follows an S-curve rather than being linear because as the population density increases, the adverse effects of high population density, such as reduced fecundity and increased mortality or the mutual interference by individuals as in the case of the azuki bean beetle (Callosobruchus chinensis), intensify. However, because all of these experiments were carried out in environments which can be considered ‘self-sustaining’ systems, limited both in space and in amount of plant material, it is not known if the same mechanisms occur in nature. Morishita’s (1950) observations show that different mechanisms do occur in nature; the many experiences of pest-control attest to the differences between controlled and natural environments. This study attempts to clarify this point by investigating the pattern of population growth of insects that are allowed a certain freedom of movement in a semi-open environment. We would like to express our appreciation to Tou Kawata, Yuasa, Shizuo Kato, Shuji Ishikura (Technical officers of the Agricultural Technology Research Institute, Entomology Section), for their guidance and support, Prof. Toshiro Uchida (Dept. of Agricultural Sciences, Kyoto University), and Shoji Hashiguchi, for his instruction on calculating saturation population density (K) using all data points rather than the traditional four points.Originating text in Japanese.Citation: Ito, Yosiaki. (1953). Studies on the Population Increase and the Movements of Soybean Aphid, Aphis glycines Matsumura. I. on the Two Types of Population Increase; II. On the Movements from Plant to Plant. Oyo-Kontyu, 8(4), 141-148.engCopyright for this item remains with the original copyright holder. Permission was obtained from the copyright holder to translate into English, where applicable, and to host the full-text content.Text