Antifeedant activity and detrimental effects of ecdysteroid agonist Chromafenozide on the food metabolic parameters of Schistocerca gregaria (Forsk.) (Orthoptera: Acrididae)
Ghoneim K, Tanani M
The desert locust S. gregaria is a dangerous pest in Egypt and other countries of North Africa and West Asia. It can devastate the cultures and crops of these areas. The present study was conducted aiming to investigate the antifeedant activity of a novel ecdysone agonist, Chromafenozide, and its effects on the different nutritional parameters of last instar nymphs. Three dose levels (10, 100 & 150 µg/nymph) were topically applied (once) onto the newly moulted last instar nymphs. Chromafenozide exhibited contradictory effects on the feeding behaviour depending on the dose since it acted as a weak antifeedant against female nymphs only at the lowest dose but acted as phagostimulant against them at the higher two doses. Moreover, it exhibited a phagostimulant activity against the male nymphs, regardless the dose level. The amount of food eaten by females along the last nymphal instar slightly decreased only at the lowest dose, but considerably increased at the higher doses. The male nymphs had been enhanced by the IGR to consume more food. RCR was slightly elevated. Treated nymphs of both sexes attained slightly or remarkably increasing relative weight gain and discharged more fecal pellets. The treated female and male nymphs achieved insignificantly increasing approximate digestibility (AD), with two exceptions for the male nymphs which had a slightly decreased AD at the medium dose and un-affected AD at the highest dose level. Both the efficiency of conversion of ingested food into biomass (ECI) and efficiency of conversion of digested food into biomass (ECD) of females slightly increased. ECI of male nymphs was promoted by Chromafenozide but ECD was slightly inhibited. Also, the effects of Chromafenozide on assimilation rate, relative metabolic rate and growth rate had been recorded.
Ghoneim K, Tanani M. Antifeedant activity and detrimental effects of ecdysteroid agonist Chromafenozide on the food metabolic parameters of Schistocerca gregaria (Forsk.) (Orthoptera: Acrididae). International Journal of Entomology Research, Volume 2, Issue 2, 2017, Pages 06-16