Functional response and consumption rate of Orius laevigatus (Hemiptera: Anthocoridae) feeding on the melon aphid Aphis gossypii (Hemiptera: Aphididae) at three different temperatures

In this study, the effect of three temperatures was investigated on the functional response of Orius laevigatus to Aphis gossypii in climatic chambers at 20, 25, and 30 ± 1 °C, 60 ± 5% RH, and 16:8 h photoperiod. Different densities of first and second instar nymphs of A. gossypii (2, 4, 8, 16, 32, and 64) on cucumber leaf discs (6 cm in diameter) were separately offered to male and female predators. After 24 h, the number of consumed preys was recorded. Ten replicates per each aphid density were used. Based on the results, predator male and female exhibited types II, III, II and III, II, III functional responses at 20, 25 and 30 °C, respectively. Handling times (Th) for males were 0.7798, 0.9177 and 0.4476 h and for females were 0.6874, 0.3921 and 0.2831 h at 20, 25 and 30 °C, respectively. Using the indicator variable method, pairwise comparisons of handling times of both males and females were significantly different. The theoretical maximum predation rate (T/Th) of both males and females were obtained at 30 °C. The results revealed that O. laevigatus is more likely to be an effective biocontrol agent of A. gossypii at higher temperatures around 30 °C. However, additional studies under natural conditions are needed to provide further details of the predator-prey interactions.