Relationship between temperature and functional response in Cardiochiles philippinensis (Hymenoptera: Braconidae), a larval parasitoid of Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

The relationship between temperature and functional response in Cardiochiles philippinensis Ashmead, a larval parasitoid of the rice leaffolder Cnaphalocrocis medinalis Guenee was examined at 6 temperatures (25, 28, 30, 33, 35, and 40°C), each at 6 host densities (1, 2, 4, 8, 16, and 32 3rd instars per arena). A type II functional response model was fit separately to each temperature; R 2 values ranged from 0.74 to 0.93. The highest attack rate was at 28°C; none of the larvae was parasitized at 40°C because the parasitoid was unable to survive. Parasitism increased from 25 to 28°C but was followed by a decrease with increasing temperature. Handling time was fitted as a quadratic function of temperature, whereas search rate was a linear function of temperature.