Some Properties and Developmental Changes in Occurrence of the Salivary Amylase of the Cabbage Bug, Eurydema rugosa MOTSCHULSKY (Hemiptera : Pentatomidae)

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In the cabbage bug the kind of enzymes in the salivary gland, the effect of hydrogen-ion conentration on salivary amylase activity, and the developmental changes in relation to the appearance of salivary protease and amylase were studied in vitro. Amylase and pectinase activities were found, but neither protease, invertase, α-glucosidase nor celulase was detected late in August. The salivary amylase was active within the range of pH 5.0∼8.0 with an optimum activity between 6.0 and 7.0. Its activity was very low in the second instar nymph and relatively high in the third, fourth, and fifth instar nymphs, reaching a miximum at the fourth instar. In the hibernated adult the activity was relatively high late in May and thereafter it lowered gradually. Late in June it was rather lower than that of the nymphs from the 3rd to 5th instar and similar to that of adult of the first generation obtained late in August. No salivary protease was detected at any developmental stage.