Effects of the wild plant, Fagonia bruguieri on the adult performance and phase transition of schistocerca gregaria (orthoptera: acrididae)

Abstract

The treatment of penultimate and last nymphal instar of Schistocerca gregaria with Fagonia bruguieri resulted in a partial blocking of the adult emergence in proportion to the concentration level, irrespective of the type of the extract. A dosedependent suppression of adult survival potential was determined after treatment of penultimate instar nymphs. Similar dose-dependent mortality of the emerged adults was recorded after treatment of last nymphal instar with the methanolic and nbutanolic extracts. With regard to the adult morphogenesis after treatment of penultimate instar nymphs with different F. bruguieri extracts, the most deranging effect was exhibited by methanolic extract. After treatment of last nymphal instar, the adult morphogenesis was considerably affected by both the methanolic extract and n-butanolic extract, parallel to the concentration. Irrespective of the time of nymphal treatment, sexual maturity of S. gregaria adults was hastened by both the methanolic extract and petroleum ether extract of F. bruguieri, especially at the higher two concentration levels. In contrast, n-butanolic extract exhibited a delaying effect on sexual maturity, especially at the higher two concentration levels. Significantly shortened longevity was recorded after treatment of penultimate instar nymphs with methanolic and petroleum ether extracts but prolonged longevity was observed after treatment with n-butanolic extract. Treatment of the last nymphal instar with n-butanolic extract, especially at the higher two concentration levels resulted in accelerated adult aging (as indicated by remarkably shortened longevity). A solitarization tendency of the gregarious adults was activated after nymphal treatment with the n-butanolic extract because some adults appeared with greenish color of both the external morphology and haemolymph.