Colonization of the Japanese Beetle in the Laboratory

Four successive generations of Japanese beetles, Popillia japonica Newman, were reared in the laboratory by feeding the larvae roots of a grass-clover mixture for 40 days, and then providing wheat roots until the transformation to prepupae or pupae. Adult emergence occurred from 126 to 300 days after egg culture; adults were fed laboratory diet developed at the Japanese Beetle Laboratory. During the study, slight refinements were made in the method of handling the larvae, to reduce contamination and losses in yield. The yield of adults from the cultured eggs increased from 5.70% for the F1 generation to 23.73% for the F4 generation. However, the number of eggs per female declined. The procedure appears to be applicable to large-scale rearing of the Japanese beetle in the laboratory.