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 of
different constant temperatures on the functional response and prey consumption of the mated female of
Neoseiulus barkeri Hughes on nymphal stages of Tetranychus urticae Koch was evaluated. Four ambient
temperatures (20, 25, 30 and 35 ± 1°C) and six prey densities (2, 4, 8, 16, 32 and 64 individuals) were
used 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. urticae
was also determined. Using the logistic regression, the type II functional response was determined for
adult female of N. barkeri at all temperatures. The type II Rogers' model was used to estimate the values
of the searching efficiency (a) and handling time (Th). The value of the searching efficiency increased
with 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 to
35°C, and the minimum value was observed at 35°C (0.5548 h). Similarly, temperature had a significant
effect on the prey consumption of adult females of N. barkeri over the range of 15-37ºC. The minimum
and maximum daily prey consumption of whole immature stages of N. barkeri was observed at 15°C and
35°C respectively. The highest and the lowest number of total preys consumed by all immature stages of
N. barkeri were 14.61 and 8.79 preys that occurred at 20°C and 15°C respectively. During the oviposition
period, 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 study
underscore the effect of temperature on searching efficiency and prey consumption of N. barkeri.