IDENTIFICATION OF RELEASE PRODUCTS OF CORPORA ALLATA OF MALE AND FEMALE ARMYWORM MOTHS, PSEUDALETIA-UNIPUNCTA

The release of juvenile hormones (JH) by female and JH acids (JHA) by male corpora allata (CA) of Pseudaletia unipuncta was monitored in vit ro using a radiochemical assay. Separation and quantification of the h omologues was accomplished by HPLC and liquid scintillation counting o f collected fractions. At emergence, CA of females maintained at 25-de grees-C, 16 h light: 8 h dark (16L:8D) released only trace amounts of JH. On days 1-2, JH III remained virtually undetectable, but similar, low quantities of JH I and JH II were released. Between days 3 and 7, an increase in the release of each homologue was observed, the largest being for JH II. Similarly, the amount of JH released by CA of female s maintained at 10-degrees-C, 12L:12D, increased as a function of age up to 25 days following emergence, with JH II again being the most abu ndant homologue. However, even after 25 days, the levels observed at 1 0-degrees-C were considerably less than those seen at 25-degrees-C. Un der conditions of 25-degrees-C, 16L:8D, males exhibited a pattern of J HA release similar to that described for females, with the exception t hat JHA I rather than JHA II was generally the dominant homologue. CA from male moths held for 5-25 days at 10-degrees-C, 12L:12D, released little JHA III, but comparatively high and similar amounts of JHA I an d II. However, contrary to the continuous age-related increase seen in females, JHA release peaked on day 10 and subsequently declined. We d iscuss these results in the context of ovarian development, pheromone production, calling behaviour and migration in armyworm females, and w e argue that JH or JH acid regulates the maturation of the pheromonal communication system in males.