Temperature-dependent functional response of mealybug destroyer, Cryptolaemus montrouzieri on citrus mealybug, Planococcus citri

Appropriate functional response to prey or host densities is one of the most important criteria for evaluating efficacy of natural enemies in biological control programs. Functional responses of the adult male and female mealybug destroyer, Cryptolaemus montrouzieri, and its 3rd instar larvae on Pseudococcus citri were studied at seven constant temperatures ranging from 15 to 40°C, % 60 ± 10 RH, and a photoperiod of 16:8h (L:D). Determination type of functional response model and estimation of related parameters were carried out based on two-stage analysis method by using SAS software. Results showed that functional responses of adult female and male coccinellids and its 3rd instar larvae were type II, except for the 3rd instar larvae at 40°C, which was type III. Estimated values for the functional response parameters showed that with increasing temperature from 15 to 35°C, searching efficiency of C. montrouzieri (adult females and males) increased, while values of handing time decreased. At 40°C, the trend was reverse and the values of searching efficiency decreased and handling time increased. In the 3rd instar larvae, by increasing temperature from 15 to 28°C,searching efficiency increased and handling time decreased. While, the trend for temperatures between 30 and 40°C was reverse. The results confirmed that functional response of the C. montrouzieri was affected significantly by temperature.