Niche overlap of parasitoids in host-parasitoid systems: its consequence to single versus multiple introduction controversy in biological control.

The importance of niche overlap between parasitoids in the single or multiple introduction problem in biological control is exhibited by mathematical analysis of one host-two parasitoid systems. To model the case where two parasitoid species show aggregative response (niches of 2 parasitoids completely overlap), the negative polynomial model is proposed. Analysis concludes that single introduction is always superior. Another new model that can cover various situations of niche overlap of parasitoids (niche overlap model) is proposed to show that single introduction is much more superior if the niches of 2 parasitoids overlap to a large extent. -from Authors