Effect of temperature on prey consumption of Typhlodromus bagdasarjani (Acari: Phytoseiidae) on Tetranychus urticae (Acari: Tetranychidae)

Abstract

ABSTRACT Typhlodromus bagdasarjani Wainstein and Arutunjan (Acari: Phytoseiidae) is a generalist predator frequently reported in plants infested by phytophagous mites or insects. In this study, we determined the daily and total prey consumption of different life stages of Ty. bagdasarjani on Tetranychus urticae Koch nymphs at constant temperatures of 15, 20, 25, 30 and 35°C, relative humidity of 60 ± 10% and a photoperiod of 16: 8 h (light : dark). The results showed a significant effect of temperature on food consumption by Ty. bagdasarjani. The number of prey consumed daily by protonymphs increased with increasing temperature from 15 (0.8 preys) to 25°C (3.5 preys), and then decreased at 30 (2.8 preys) and 35°C (3.1 preys). The daily predation of the other life stages of Ty. bagdasarjani followed a similar trend as that which occurred in protonymphs, with the exception of post-oviposition period, in which the highest values for the mean prey consumption were observed at 30°C (6.6 preys/day). The highest means for the daily and total prey consumption of females were observed during oviposition, when they devoured an average of 2.7, 5.3, 10.1, 10.9, and 11.0 prey/day and 173.7, 255.9, 244.8, 259.0, and 185.8 prey in their entire period of oviposition at 15, 20, 25, 30, and 35°C, respectively. During adult life, the maximum number of prey was consumed at 20°C (432.7), which may be because of the longer period of adulthood at lower temperatures. Therefore, the efficiency of this predator in control of T. urticae populations could be higher at temperatures of above 20°C.