Effects of juvenile hormone analogue treatment in adult females of the ovoviviparous cockroach, Blaptica dubia (Dictyoptera, Blaberidae)

Abstract

Adult females of the ovoviviparous Argentinian cockroach, Blaptica dubia, were repeatedly treated with either 100 μg methoprene or 100 μg pyriproxyfen in 5 μL acetone either during the first vitellogenic cycle or during the period of gestation. Treatment during the first vitellogenic cycle (days 2–20 of adult life) did not inhibit vitellogenesis and oocyte growth, but prevented the formation of an ootheca. This was accompanied with a significant reduction of the titer of juvenile hormone (JH) III and an increased amount of ecdysone (E) and 20-hydroxyecdysone (20E) in the haemolymph of the animals. Treatment of adult females during the period of gestation (days 30–70) resulted in a complete degradation and resorption of the ootheca and induced another vitellogenic cycle. Again, this was associated with a decrease in haemolymph JH III titer, but an increase in the concentrations of free ecdysteroids.