Figure 1. Vitellogenin synthesis in penultimate and last instar nymphs of Leucophaea maderae. A single dose of 400µg of methoprene was topically applied at the days indicated. Five days later the animals were radiopulsed for 4 hours, bled, and the vitellogenin precipitated from aliquots by anti-vitellogenin. Control animals had received 5µl of acetone by topical application. No vitellogenin synthesis was induced by acetone treatment. Columns represent averages SE of the mean. Numbers above the columns are the number of animals used. Unpublished data from Don-Wheeler, 1996.