Host location inOlesicampe monticola, a parasite of larvae of larch sawflyCephalcia lariciphila.

In the laboratory, ovipositor probing in mated femaleOlesicampe monticola was elicited by freshCephalcia lariciphila frass but not by aged frass or freshly spun larval silk. Second instar sawfly larvae andLarix needles also elicited a low level of ovipositor probing. Extracts of frass in dichloromethane, but not hexane, were also active. No difference in response was found to frass fromC. lariciphila larvae fed on three varieties ofLarix, (L. kaempferi, L. decidua andL. × eurolepis).