Precocene II has juvenile-hormone effects in 5th instar Locusta migratoria

Precocene II can cause juvenilization of 5th instar Locusta migratoria. The adultoids and supernumerary larvae produced following precocene treatment are morphologically indistinguishable from adultoids produced by treatment with a JH-analogue, while the CA are markedly reduced in size or absent. The time-response curves for the induction of juvenile characters and for the degeneration of the CA suggest that the CA may be active during the early 5th instar. The CA are necessary for juvenilization to occur in response to precocene, and the effect is probably the result of synthesis or release of JH during the breakdown of the glands.