The influence of temperature on the functional response and prey consumption of Neoseiulus barkeri (Acari: Phytoseiidae) on Tetranychus urticae (Acari: Tetranychidae)

The foraging behavior of a natural enemy is greatly affected by temperature. The influence ofdifferent constant temperatures on the functional response and prey consumption of the mated female ofNeoseiulus barkeri Hughes on nymphal stages of Tetranychus urticae Koch was evaluated. Four ambienttemperatures (20, 25, 30 and 35 ± 1°C) and six prey densities (2, 4, 8, 16, 32 and 64 individuals) wereused during a 24-h period in functional response experiments. The effect of seven constant temperatures(15, 20, 25, 27, 30, 35 and 37 ± 1°C) on prey consumption of N. barkeri on nymphal stages of T. urticaewas also determined. Using the logistic regression, the type II functional response was determined foradult female of N. barkeri at all temperatures. The type II Rogers' model was used to estimate the valuesof the searching efficiency (a) and handling time (Th). The value of the searching efficiency increasedwith increasing temperature from 20 to 30°C (0.0364 to 0.0731 h-1 respectively), then decreased at 35°C(0.0646 h-1). The handling time of this predator decreased when the temperature increased from 20 to35°C, and the minimum value was observed at 35°C (0.5548 h). Similarly, temperature had a significanteffect on the prey consumption of adult females of N. barkeri over the range of 15-37ºC. The minimumand maximum daily prey consumption of whole immature stages of N. barkeri was observed at 15°C and35°C respectively. The highest and the lowest number of total preys consumed by all immature stages ofN. barkeri were 14.61 and 8.79 preys that occurred at 20°C and 15°C respectively. During the ovipositionperiod, the total prey consumption increased with increasing temperature from 15 (160.43 preys) to 30°C(286.71 preys) and then declined and reached to 191.57 preys at 37°C. The results of this studyunderscore the effect of temperature on searching efficiency and prey consumption of N. barkeri.