Larvae of the woodwasp, Sirex cyaneus, contain midgut digestive enzymes that enable them to utilize the major fungal and plant polysaccharides found in their food. At least two classes of enzymes, the Cx-cellulases and the xylanases, are not produced by the larvae. Instead, larvae acquire these enzymes while ingesting tissue of Amylostereum chailletii, the fungal symbiont that occurs in the wood on which the larvae feed.