The juvenile hormones in blood of larvae and adults of Manduca sexta (Joh.).

The juvenile hormones (JH) in extracts of Manduca sexta blood were converted to 10-(2,4-dichlorobenzoyloxy)-11-methoxy derivatives and quantitatively determined by gas chromatography with electron capture detection. Early IVth instar larvae contained 0.62 ng JH-I, 1.1ng JH-II and 0.07 ng JH-III per ml blood. Early Vth instar larvae, and adult of both sexes contained the hormones in concentration from 0 to 0.24 ng/ml blood. No hormone was detected in late Vth instar (wandering) larvae. The detection limit in our experiments was less than or equal to 0.003 ng/ml blood.