Abstract
The functional response of Spalangia endius Walker was described by a linear relationship between attack rate and density of house fly pupae. S. endius searched well at higher host densities and in 72 h, appeared capable of attacking more than 80 pupae per female under laboratory conditions. The response of Muscidifurax raptor G. & S. was quadratic as poor searching ability limited this parasitoid’s attack rate at high host densities. Individual parasitoid efficiency of both species was reduced by intraspecific competition when parasitoid density was increased.