... Fletcher et al., 1994; Heimpel and Rosenheim,1995; van Randen and Roitberg, 1996), in ®eld cages (Prokopy et al., 1994) and in insects foragingfreely in the ®eld (Odendaal and Rausher, 1990; Tatar, ... variability in insect foraging and oviposition behaviour. Oikos 65, 134±142.Morrison, G. and Strong, D.R. (1981) Spatial variation in egg density and the intensity of parasitism in aneotropical ... state-variable model (Mangel and Clark, 1988) to determineoviposition behaviour, keeping the deterministic setting. The dynamic model explicitly incorpo-rates the host encounter rate and thus allows clutch...