Wind and light are major climatic factors which affect host-location process in parasitoids, but these environmental effects have not been studied thoroughly. Wind-tunnel experiments were designed to dissect how changes in wind velocity and light intensity influence flight initiation, flight orientation and host-searching efficiency in Cotesia glomerata. This study uncovers the influences of changes in wind velocity and light intensity on different phases of host-location process in the parasitoid. These results suggest that a cloudy and/or windy weather may reduce the success of host location by C. glomerata because such conditions suppress flight initiation, cause failure to orientate flights to the herbivore-infested plant and hamper host-searching activity on the plant. none