DEGRADATION OF WOOD IN THE DIGESTIVE-TRACT OF A HIGHER TERMITE, NASUTITERMES TAKASAGOENSIS (SHIRAKI) (ISOPTERA, TERMITIDAE)

A wood-feeding higher termite, Nasutitermes takasagoensis (Shiraki) wa s employed for observing the biodegradation of mood fragments in the d igestive tract using a scanning electron microscope. The contents of t he foregut were wood fragments of two sizes, 10-30 mu m and 1000-300 m u m, similar in to the morphological characteristics of fed wood meal. Wood fragments in the first part of the hindgut just anterior to the enteric valve varied in size consecutively from less than 10 mu m to 3 00 mu m, indicating severe enzymatic degradation. The hindgut posterio r to the enteric valve was swollen and the contents of the posterior p art consisted of a small amount of wood fragments of the size of 50-30 0 mu m, and many smaller (less than 10 mu m) and random-shaped particl es which appeared to be digestive residues. These observations suggest the following wood degradation mechanism by N. takasagoensis: 1) Degr adation and the following down-sizing of ingested wood fragments by th e termite's enzymes in the midgut and the hindgut anterior to the ente ric valve, 2) Final decomposition of down-sized fragments in the hindg ut posterior to the enteric valve.