In a laboratory study, the ovipositionai preference of Plutella xylostella on wild crucifers (Brassica nigra, Cardamine integrifolia and Erysimum cheiranthoides) were similar to the searching preference of its main parasitoid Diadegma insulare on the same plants. However, on cultivated crucifers (2 varieties of B. oleracea), these species had opposite preferences. Also, the ovipositional eferences of P. xylostella did not correlate with growth and reproduction on several food plants. The patterns of behaviour were considered as evidence of evolution for use of enemy-free space in agricultural systems. Plutella xylostella; FOOD-PLANTS; Cruciferae; Preferences, reproduction & parasite oviposition site relations; FOOD-PREFERENCES; Reproduction & hymenopteran parasite oviposition site relations; EGG-LAYING; Site preferences, hymenopteran parasite oviposition site relations; FECUNDITY-; GROWTH-; Food plant preferences significance; HYMENOPTERAN-PARASITES; Diadegma insulare; Food plant preferences, parasite oviposition site relations Diadegma insulare; BREEDING-SITE; Oviposition site, relations with lepidopteran host food plant preferences; EGG-LAYING; Site, lepidopteran host oviposition site on food plant relations; LEPIDOPTERAN-HOSTS; Plutella xylostella; Host food plant preferences, parasite oviposition site relations none