FEEDING PREFERENCE AND THE INFLUENCE OF PREY STAGE Bemisia tabasi (Genn.) ON SOME BIOLOGICAL CHARACTERS OF THE PREDATOR Clitostethus arcuatus (ROSSI) ON COTTON

Abstract

Several laboratory experiments were conducted to evaluate the feeding preference and the influence of prey stages of the white fly Bemisia tabasi (Genn.(Aleyrodidae:Homoptera) on some biological aspects of the predator Clitostethus arcuatus (Rossi (Coccinellidae: Coleoptera). The consumption time required by predator stages for each white fly stage was calculated too. Results showed that predator larvae preferred white fly egg for feeding and development. The number of preys was decreases with their size increase and was increase with the increase of the developmental stages of the predator. Females of the predator preferred the first nymphal stage (crawlers) fallowed by egg and the subsequent nymphals stage while the adult stage of the white fly was the least preferred host. The adults males preferred the egg stage followed by the subsequent nymphal stage and finally the adult stage of white fly. The best predator larvae performance was obtained when fed on diet of mixed stage of the prey. The shortest life span for larval and pupal stages combined and the highest survival rate were 15 days and 88.9% recorded for predator larvae fed on mixed diet of egg and nymphs, while the longest life span and lowest survival rates were 17.7 days and 85.7%recorded for individuals fed on white fly egg alone. Results also indicated that time of prey consumption was reduced as predator stage increase in size and was increase with the progress of white fly development stage. The longest adult longevity and female fecundity were obtained when the predator fed on food of all white fly satages.