| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1995: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1994: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
1.The sterilizing mechanism of gamma-radiation in the female melon fly, Dacus curcurbitae was studied histopathologically. In irradiated females, differentiation of 1st-follicle from the germarium was completely inhibited. Oogonia caused pycnosis and karyolysis. Collapsed and condensated cell materials were fused, and the germarium was vacuolized. After aging of irradiated flies, the midgut epithelium became thinner, and thread-like microoraganisms were found abundantly in the lumen of the posterior portion of the midgut. Observation demonstrated that gamma-radation of 70Gy caused complete inhibition of oogenesis. The midgut epithelium was damaged by gamma-radiation, which might cause a deficiency in nutritive supply and possibly contribute to the short life span of irradiated flies.
2.The sterilizing mechanism of gamma-radiation in the sweet potato weevil, Cylas formicarius, effects of gamma-radiation on the gamatogenesis and embryogenesis were studied histologically. By gamma-radiatio
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n, the spermatogenesis was inhibited ; the spermatogonia and spermatocyte had almost completely collapsed and spermatozoa in the seminal vesicle markedly decreased. In the eggs oviposited by the normal females which had mated with irradiated males, the normal embryogenic prosess was inhibited, which caused dominant lethal mutatation of fertilized eggs. By gamma-radiation in the females, oogenesis was inhibitedcompletely, which resulted in inhibition of oviposition of females. It was indiated that susceptibility of reproductive tissue against gamma-radiation was higher in females than in males.
3.Reproductive properties of the sweet potato weevil was studied by the rearing experiments. Males and females were fertile until death from the 7th day after eclosion. Males mated repeatedlly throughout ther lives. Females laid tota164 eggs on average throughout the life and rarely remated because secretion of the pheromone was inhibited after the first mating. The females oviposited with irrespective of potato size. Less
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