Abstract

Development, feeding capacity and life table parameters of the predatory mite Typhlodromips swirskii (Athias-Henriot) fed three different levels of whitefly eggs Bemisia tabaci Genn. were studied under laboratory conditions of 26°C and 70% RH. Both organisms were collected from eggplant leaves growing in an greenhouse in Al-Qassim region, center of Saudi Arabia in 2009. In leaf disc assays, increasing number of prey eggs accelerated the development of T. swirskii. Duration of developmental stages and feeding capacity of T. swirskii were significantly affected by the number of whitefly eggs offered. During an ovipositional period of 13.1, 18.9 and 19.5 days, adult female of T. swirskii consumed an average of 41.6, 128.4 and 140.1 prey eggs when each female was provided with 4, 8 and 12 prey eggs day-1 and laid an average of 10.5; 12.8 and 15.7 eggs day-1, respectively. Offering the predatory mite with 4, 8 and 12 prey eggs day-1 caused a mean generation time (T) of T. swirskii was 17.15; 17.66 and 15.45 days while, the net reproductive rate (Ro) averaged 10.86, 20.98 and 22.12 female progeny/female and the intrinsic rate of increase (rm) of T. swirskii was 0.22, 0.17 and 0.14 female progeny/female/day, respectively. The finite rate of increase erm (λ) was at its highest level (1.23) when T. swirskii individuals was provided with 12 eggs day-1 and declined to 1.19 and 1.15 after feeding on 8 and 4 prey eggs day-1, respectively. Crowding of T. swirskii significantly decreased feeding capacity and egg deposition.