Temperature Influences Functional Response of Anisopteromalus calandrae (Hymenoptera: Pteromalidae) Parasitizing Maize Weevil Larvae in Shelled Corn

The functional response of Anisopteromalus calandrae (Howard) attacking Sitophilus zeamais Motschulsky on shelled corn was measured at constant temperatures of 20, 25, 30, and 35°C. Separate random parasite equations (Rogers, D. J. 1972. Random search and insect population models. J. Anim. Ecol. 41: 369-383) were fit to the number of progeny produced in 1 d. Temperature was incorporated into Rogers' equation by making both the attack coefficient (a) and handling time (Th) functions of temperature. The attack coefficient was fitted as an exponential function and handling time as an inverse function of temperature. The resulting four-parameter composite model fit the data as well as the separate Rogers' equations, although the predicted functional response plateau at temperatures >20°C tended to be lower than those of the Rogers' equations.