天蚕及び柞蚕の交尾に関する研究 : 第5報天蚕蛾, 柞蚕蛾並びにその交配蛾の不受精卵

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It is a pressing problem in the production of the wild silkworm eggs to determine whether the low fertility of these eggs is attributable to the meagre copulation ratio of their parent moths or instinctively originates in the laid eggs themselves that contain numerous unfertilized eggs. To clarify this point, experiments were made on the 15th, the 18th and the 20th of August, 1952,by the use of the moths emerged on the same day from the cocoons reared at the Ariake Wild Silkworm Experiment Station, Nagano Prefecture. For the purpose of the sample test, a pair of the moths were put in a moth cage which was hung under a cedar tree to protect it from the direct ray of the sun and which was covered with 0.3cm mesh to avoid other male moths to stray into. After these moths had died the laid eggs were tested. Those eggs of A. pernyi ♀×A. pernyi δ, A. pernyi ♀×A. yamamai δ and A. yamamaia ♀×A. pernyi δ, hatch 10-11 days after laying and since microscopic observation reveals that not any developemeot of embryo is seen in the unhatched eggs, the hatched eggs were, in this test, classified as fertilized eggs and the unhatched ones as unfertilized ones. Though A.yamamai eggs are hybernating, the embryos develop nearly to the full size within ten days after they had been laid, so that microscopic observation is competent in detecting the fertility of them. The results shown in Tables 1-3. are summarized as follows : - (1) The A. pernyi eggs (A.pernyi ♀×A. pernyi δ) are nearly satisfactory in fertility. (2) Concerning the A. yamamai eggs (A. yamamai ♀×A. yamamai δ), the ratio of the unfertilized eggs is so great as about 70 per cent. The scrutinization into the individual layiigs, however, shows that there are two kinds of layings regarding fertility ratio, that is, the one is those layings, the fertility ratio of which is nearly perfect, and the other is the ones, whose fertility ratio is null. There exists good coincidence between the copulation ratio of the moths of this species and the unfertilized ratio of the laid eggs. Moreover, those moths, whose copulations the writers had ascertained, laid without fail, perfect fertilized eggs. Hence the existence of numerous impotent male moths is responsible to the low fertility of the laid eggs, that is, those moths as were successful in copulating lay fertilized eggs and those which were unsuccessful, on the contrary, laid unfertilized ones. (3) The eggs of A.yamamai ♀×A.pernyi δ are low in fertility because presumably of the unsmoothness of the mating between the different species. (4) The eggs of A.pernyi ♀×A.yamamai δ are extraordinarily low in fertility ratio. This obstacle in this industry will be, perhaps, attributable to the additive effect of the cause mentioned in (3) and the existence of numerous impotent male A.yamamai moths as is the case of (2) though the writers hope to study this problem further.
日本生態学会の論文
1956-01-31

天蚕及び柞蚕の交尾に関する研究 : 第5報天蚕蛾, 柞蚕蛾並びにその交配蛾の不受精卵

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天蚕及び柞蚕の交尾に関する研究 : 第5報 天蚕蛾, 柞蚕蛾並びにその交配蛾の不受精卵

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天蚕及び柞蚕の交尾に関する研究 : 第5報天蚕蛾, 柞蚕蛾並びにその交配蛾の不受精卵