Phosphatase and Esterase Polymorphism in Larvae of the Silkworm, Bombyx mori L. (Lepidoptera : Bombycidae)

Abstract

The present paper is a resume of the polymorphism of enzymes of 300 silkworm strains obtained by the analysis of the blood acid phosphatase, the blood esterase, the mid-gut alkaline phosphatase and the integument esterase activity by electrophoretic separation. The distributions of the blood acid phosphatase and the blood esterase types in Japanese and European races, are similar, whereas there is very little resemblance in Chinese and European races. The alkaline phosphatase zymogram of the mid-gut can be resolved into two isozymes (F and S). Strains that belong to F isozyme negative type are very few, and the frequency of appearance of S isozyme negative type was observed to be comparatively high : about 15 per cent of the tested strains belong to the latter type. It is noteworthy that the frequency of appearance of this type is especially high in Japanese race and extreamely low in European race. The esterase activity of the integument can be classified into six types. The strains belonging to Japanese race showed very high frequency of C type and low frequency of B type, while those belonging to Chinese race showed high frequency of both the types. It is conspicuous that the complex types such as AB and AC types are about 30 per cent of the whole showing high frequency in European race.