天蚕及び柞蚕の交尾に関する研究 : 第6報 天蚕の交尾蛾と交尾不能蛾の産卵

抄録

Since the copulation ratio of A. yamamai is not only low but also the copulation itself is usually difficult to observe, a discovery of some characteristics of layings between the copulated moths and the uncopulated, viz. virgin moths should be of great benefit to this industry. On the July 29th, 1953,the writers experimented upon ten pairs of A. yamamai moths, each of which was put in a separate moth cage hung in the open near the house, when the room temperature was 23.0°〜26.5C and the humidity was 68〜86%. After the observations through two successive nights, it was found that only three pairs were successful in copulation, that is, they began to copulate from 1 : 37 a.m., 1 : 43 a.m. and 2 : 20 a.m. of the 31st of the month. Then every male moth was removed from the cage to watch the behavior of the lonesome female moth. The layings of the copulated moths were made almost exclusively approximately as many as four-fifths of the total eggs-in the successive night of copulation, viz, on the third night of this experiment, with rapid decrease thenceforth. The eggs remaining in the mother body were few. As to the virgin moths, however, they laid only a few eggs in the third night, and continued for several days thenceforth. Therefore the fertility of the egg is predictable from the date of its laying, in other words, the eggs laid in the third night of pairing are without exception fertile, whereas those laid thenceforth are almost unfertile. The pairing of the once copulated male moth with a virgin female moth is of great interest, but the study must be reserved, for another opportunity.