Functional response of Telenomus remus (Hymenoptera: Scelionidae) to the fall army worm eggs

Abstract

The functional response of the parasitoid wasp, T. remus, was studied at various densities (25, 50, 75, 100, 125, 150, 200 and 250 eggs/tube) of its host, the fall army worm, Spodoptera frugiperda. One-day-old parasitoid females were individually exposed during 24 h to 0- to 24-hour-old host eggs. The parasitism ranged from 17.0 to 99.8 parasitized eggs at densities of 25 and 250 host eggs, respectively. Various types of mathematical models were applied to the parasitism data using regression analysis to determine the relationship between the number of parasitized hosts and host densities. The values of F and R2 were used as criteria for evaluating the models. Functional response curves corresponded best to that of Holling model. Search rate ranged between 0.79 and 0.37 eggs/egg at the densities of 50 and 250 eggs, while time of oviposition varied from 0.062 to 0.011 days/egg at the densities of 25 and 200 eggs, respectively.