Functional response of microplitis pallidipes parasitizing Spodoptera frugiperda.
Objectives: To evaluate the effectiveness of parasitism by Microplitis pallidipes Szepligetion on Spodoptera frugiperda (J. E. Smith) larvae. Methods: We studied the functional response, search rate and effect of intraspecific competition, on the parasitism rate of M. pallidipes on S. frugiperda larvae at five different temperatures (20, 23, 26, 29 and 32°C), in a laboratory. Results: The functional response of M. pallidipes on fitted a Holling type II model at all five temperatures. At the same temperature, the parasitism rate increased with host density up to a certain level after which it tended to stabilize. The parasitic efficiency of M. pallidipes was affected by temperature. The parasitic efficiency (a/Th) was highest at 29°C and lowest at 20°C. Search effectiveness gradually decreased with increasing density of both the host species and M. pallidipe. Simulation with the Hessell-varley model suggests that both search effect and search efficiency decrease with increasing density of parasitic wasps. Conclusion: Temperature affects parasitism by M. pallidipes on S. frugiperda and intraspecific competition between M. pallidipes reduced the parasitism rate.