Abstract: The larval-pupa parasitoid Theocolax elegans was evaluated as a biological control agent against the rice weevil, Sitophilus oryzae, in stored wheat. The parasitization and host-feeding of the parasitoid at six constant temperatures (17-32℃) were determined in the laboratory. The functional response of T. elegans parasitizing S. oryzae was examined over a range of temperatures and host densities. A functional response equation was fitted to each temperature regime. Within the temperature range of 17℃ to 29℃, the handling time was inversely proportional to temperature, and ranged from 0.333 d at 17℃ to 0.063 d at 29℃. Instantaneous search rate also changed with temperature and was the lowest at 17℃ and highest at 26℃. But over 29℃, the instantaneous search rate decreased significantly as the temperature increased. A temperature-mediated functional response equation was fitted to the data, in which handing time was a quadratic function of temperature. T. elegans can parasitize greater numbers of hosts within the temperature range of 26℃ to 29℃.

Key words: Theocolax elegans, Sitophilus oryzae; temperature, biological control, functional response