Influences of varying host: parasitoid ratios on parasitism of whitefly by three different parasitoid species

Abstract

Abstract This study reports the effects of different host: parasitoid ratios on parasitic behavior and functional response of three different parasitoid species (Eretmocerus sp. nr. furuhashii, Encarsia bimaculata, and Encarsia sophia) attacking the sweetpotato whitefly, Bemisia tabaci, under laboratory conditions. The parasitic ability of three parasitoid species was significantly influenced by the whitefly density. Increasing host density had beneficial effect on parasite efficiency of Er. sp. nr. furuhashii, E. bimaculata, and E. sophia. The rate of instant attack (a) observed for Er. sp. nr. furuhashii, E. bimaculata, and E. sophia was 0.1649, 0.1113, and 0.0655, respectively. Total parasitic time (T h ) observed for Er. sp. nr. furuhashii, E. bimaculata, and E. sophia was 0.0737, 0.2325, and 0.1936, respectively. In the second experiment, the parasitical action was also influenced by parasitoid density. At constant host density, the rate of parasitism increased with parasite density up to a certain density followed by a decrease in rate of parasitism with increasing parasitoid density.

Keywords

• Bemisia tabaci
• Parasitoids
• Density
• Interference