Age-specific functional response and predation rate of Amblyseius swirskii (Phytoseiidae) on two-spotted spider mite

Abstract

The lifetime functional response and predation rate of Amblyseius swirskii Athias-Henriot on eggs of the two-spotted spider mite, Tetranychus urticae Koch were determined under laboratory conditions using cucumber leaf discs. Densities of 2, 4, 8, 16, 32, 64 and 128 prey were offered to 3, 4, 5, 6, 7, 12, 17, 22 and 27-day-old A. swirskii individuals. Based on the logistic regression, the functional response of twelve-day-old A. swirskii was type III, while the other ages showed type II. The Rogers model was used to estimate searching efficiency (a) and handling time (Th). The longest handling time (1.387±0.315 h) was observed in the protonymphal stage, while the shortest handling time and highest maximum attack rate (T/Th) were estimated at the age of seven-days (0.396±0.057 h and 60.67 prey/day, respectively). In the functional response experiments, results of the highest prey density used (128 eggs) showed that the highest number of prey consumed by A. swirskii individuals aged twelve and seventeen-days old (35.6 and 43.1 eggs, respectively). It is concluded that A. swirskii could be an efficient biological control agent of T. urticae at the middle-age of its life and at higher prey densities.