Do host species influence the performance of Encarsia formosa, a parasitoid of Bemisia tabaci species complex?

The whitefly Bemisia tabaci (Gennadius) is a globally distributed species complex that includes several destructive pests of agriculture. In recent years, the high ability of B. tabaci to develop insecticide resistance indicates that using insecticides to control this pest has become unsustainable. Use of natural enemies as part of integrated management approaches is considered a key strategy for long term sustainable control. Here we investigated the effects of host species on the performance of a parasitoid. We tested this using Encarsia formosa Gahan (Hymenoptera Aphelinidae) and two members from B. tabaci species complex, MEAM1 and AsiaII7. The parasitoids were reared using MEAM1 or AsiaII7 hosts feeding on hibiscus. Those maintained on MEAM1 are referred to as M-E. formosa and those on AsiaII7 as A-E. formosa. Results showed that there were no significant differences between the pre-imaginal developmental times of M-E. formosa and A-E. formosa regardless of their whitefly hosts. However, M-E. formosa emergence rate after parasitism on MEAM1 was higher than that of A-E. formosa parasitizing MEAM1. On the contrary, A-E. formosa emergence rate after parasitism on AsiaII7 was higher than that observed for M-E. formosa parasitizing AsiaII7. In no-choice experiments, M-E. formosa females parasitized MEAM1 and AsiaII7 hosts in a similar rate but A-E. formosa parasitized less MEAM1 than AsiaII7 hosts. In choice experiments, M-E. formosa females parasitized more MEAM1 than AsiaII7 hosts and A-E. formosa parasitized AsiaII7 and MEAM1 hosts equally. These parasitism rates mirrored for the host checking and oviposition behavior of different E. formosa strains. Our results indicate that B. tabaci species does not influence parasitoid development period until adulthood, but that pre-imaginal experience is important for emergence rate, parasitism rate and behavior of E. formosa adults.