none The host searching behaviour and short-range host location by parasitoids of the Eurasian spruce bark beetle, Ips typographus , were examined in order to repeat, using another scolytid-parasitoid system, that observation by Richerson and Borden that host metabolic heat radiation is the principle method of host location by scolytid parasitoids. Differences in searching behaviour of the braconid parasitoids, Coeloides bostrychorum and Dendrosoter middendorffii , and the pteromalid, Rhopalicus tutela , are described. Experiments using both an infra-red scanner and thermistor probes failed to detect "hot spots" associated with susceptible hosts beneath the spruce bark. Deep-freezing and host removal treatments of scolytid infested spruce logs indicated that host vibrational cues were unnecessary for successful host location by parasitoids. The role of volatile chemical cues was investigated using both barriers and implantations on logs. Cellulose barriers did not disrupt host location, while wax barriers disrupted host location for up to 24 h.