Sexual Dimorphism in Juvenile Hormone Synthesis by Corpora Allata and in Juvenile Hormone Acid Methyltransferase Activity in Corpora Allata and Accessory Sex Glands of Some Lepidoptera

Summary 1. Corpora allata of adult Manduca sexta and Heliothis zea are sexually dimorphic in that females produce juvenile hormones (JH) while males lack JH acid methyltransferase and therefore produce JH acid. Male and female CA of Vanessa cardui contain JH acid methyltransferase.2. Male but not female reproductive tract tissues of M. sexta, H. zea, and V. cardui contain JH acid methyltransferase activity. The enzyme is absent from male and female reproductive tracts of Blaberus discoidalis, Oncopeltus fasciatus and other non-lepidopteran species.3. It is suggested that sexual dimorphism with regard to JH acid methyltransferase in CA of adults is restricted to moths and that the ability to methylate JH acids in the male reproductive tract is a characteristic of Lepidoptera.