Developmental, Morphogenetic and Reproductive Effects of Four Poly cyclic Non-isoprenoid Juvenoids in the German Cockroach (Dictyoptera: Blattellidae)

Developmental, morphogenetic, and reproductive effects of four polycyclic non-isoprenoid juvenoids (fenoxycarb, pyriproxyfen, CGA45128, and PH030) were compared in nymphal German cockroaches, Blattella germanica (L.). A pronounced dose-dependent response was exhibited with all juvenoids. Ecdysial failure was induced at 100 and 10 μg by fenoxycarb, CGA45128 and PH030, while pyriproxyfen did not cause this effect at any dose tested. All juvenoids induced significant developmental delays (at doses of 100, 10 and 1 μg/insect) and caused high levels of morphogenetic wing twisting, with PH030 being significantly more active than the other compounds. Twisted-wing adultoids were capable of reproducing unless they had been treated at 100 or 10 μg; PH030 was the only compound causing reproductive inhibition at the lower 1 μg dose. Wing twisting was not an absolute indicator of reproductive inhibition, as most slightly affected adultoids were capable of producing progeny when mated with normal adults. The implications of this latter finding to German cockroach population management with juvenoids is discussed.