Age-specific functional response and predation capacity of Phytoseiulus persimilis (Phytoseiidae) on the two-spotted spider mite

Abstract

The lifetime-dependent functional response and predation rate of Phytoseiulus persimilis Athias-Henriot on eggs of the two-spotted spider mite, Tetranychus urticae Koch was determined under laboratory conditions using cucumber leaf discs. Densities of 2, 4, 8, 16, 32, 64 and 128 prey were offered to 4 (protonymph), 5 (deutonymph), 6 (1-day-old adult), 10 (5-day-old adult), 15 (10-day-old adult), 20 (15-day-old adult), 25 (20-day-old adult), 30 (25-day-old adult), 35 (30-day-old adult) and 40 (35-day-old adult) P. persimilis individuals. The results of logistic regression analyses showed that on the 15th, 35th and 40th days of predator age, predation rate of T. urticae eggs increased, resulting in the type III functional response, while at the other ages, the functional response was type II. The Rogers model was used to estimate searching efficiency (a) and handling time (Th). The longest handling time was obtained in the protonymphal stage with 2.377 +/- 0.192 h. The shortest handling time and the highest value of estimated maximum attack rate (T/Th) were estimated at the age of 20 days (0.494 +/- 0.009 h and 48.57prey/day). At the highest prey density used (128 eggs), our findings showed that the highest number of prey was eaten by 15, 20, 25 and 30 days old P. persimilis (39.3, 41.7, 39.3 and 38.1 eggs per day, respectively). The results of this study revealed that P. persimilis especially at the middle and late ages has a good predation potential on T. urticae eggs at higher prey densities.