none The ratio of increase of parasitoids from generation to generation with host densities largely depend on their searching activity and responses to variable host densities. The present host parasitoid model suggests parasitoid-searching ability and reproductive potentiality which are optimum for their selection in biocontrol. However, few attempts have been made on the aspects of host/parasitoid interaction. Early second instar larvae of E. atomosa were exposed in densities of 10, 20, 30, 40 and 50 to a mated female parasitoid for 24 hr fed on fresh pigeonpea pods and 20% honey. Reproduction; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Host parasite relationships; Ecology; Population dynamics Exelastis atomosa (Pterophoridae); Hymenopteran parasites; Cotesia diurnii; Density, influence on parasite prevalence & reproductive productivity; Prevalence; Cotesia diurnii (Hymenoptera), relationship with host density; Population density; Hymenopteran parasite prevalence & reproductive productivity relations Cotesia diurnii (Braconidae); Reproductive productivity; Lepidopteran host density relationship; Lepidopteran hosts; Exelastis atomosa; Host density, influence on prevalence & reproductive productivity; Prevalence; Exelastis atomosa (Lepidoptera), relationship with host density