Distribution of cellulase activity in the salivary glands and the guts of pseudoworkers and soldiers of the drywood-feeding termite Neotermes koshunensis (Shiraki) and the effect of Defaunation

Abstract

Distributions of two types of cellulase activity (endo-β-1,4-glucanase [EC 3.2.1.4] and β-glucosidase [EC 3.2.1.21]) were measured in the salivary glands and the gut of the xylophagous termite Neotermes koshunensis, and activity was compared among pseudoworker-caste insects, soldier-caste insects and defaunated pseudoworkers in which the symbiotic flagellates were removed by exposing the termites to sunlight for 120 min. Strong cellulase activity was detected in the salivary glands and the hindgut of the pseudoworkers, while the defaunated termites showed a marked reduction in cellulase activity of the hindgut. The salivary glands of soldier termites showed significantly lower cellulase activity than those of pseudoworkers, whereas the hindgut of the soldiers possessed a similar level of activity to that of the pseudoworkers. The present results suggest that the hindgut is the primary site of cellulose digestion in pseudoworkers and soldiers of N. koshuensis, and that the salivary cellulases also play an indispensable role for cellulose digestion in pseudoworkers.