シロチョウ類の孵化過程 : II. モンシロチョウ卵の色彩変化と生存率

Superficial change in eggs of Pieris rapae crucivora BOISDUVAL was observed after oviposition using a stereoscopic microscope. The color of the vitelline membrane through the chorion changed from pale yellow to bright yellow in 20 hours, to strong yellow in 40 hours and to bright yellowish orange at the tip in 69 hours after oviposition. The luster of the chorion disappeared after 37 hours. The vitelline membrane was separated from the chorion after 43 hours. The mandible, the eyespot and the head were appeared 52, 55 and 62 hours after oviposition. The duration of egg stage (total 73 hours) could be classfied into four stages: 'stage I', 'stage II', 'stage III' and 'stageIV' was about 20, 20,30 and 4 hours, respectively. This result was applied to examine the stage structure of the eggs in the field. The life table for the egg stage was also constructed