The effects of applying varying doses of an antibiotic to fifth instar larvae of Philosamia ricini on the silk glands were studied. Transaminases were increased by low doses, while RNA accumulation was reduced after administration of tetracycline. The levels of DNA showed little response to treating with antibiotic. However, the incorporation of amino acids into silk proteins was generally increased. The overall effects on the silk gland was reflected by its weight, cocoon weight, quantity of raw silk and quality of silk. All these indices were improved by administration of tetracycline.
