<Original>Studies on Digestive System of Termites III. : Digestibility of Xylan by Termite Reticulitermes speratus (Kolbe)

Abstract

Worker termites of Reticulitermes speratus (Kolbe) were fed with various carbohydrates related to wood polysaccharides and 1% acetic acid for 21-days, and changes of survival and weight of termites and protozoan fauna were monitored. The results indicate that the diets can be grouped into four types (Type I to IV) in respect of utilization by protozoa and termite. Type I includes Akamatsu sapwood and cellulose in which large size protozoa, Trichonympha agilis and Teratonympha mirabilis, take part in digestion. Type II includes CMC and xylan in which smaller size protozoa, Pyrsonympha sp. and Dinenympha sp., take part in digestion. This was supported by xylanolytic enzyme analysis which indicated that about 70% activity of xylanase still remained in the hindgut of workers after feeding with xylan for 21 days. Type III includes amylose, cellobiose, sucrose, maltose, glucose and fructose which are usable by termites without an aid of the protozoa. Type IV includes the other hemicelluloses and monosaccharides and acetic acid, which are not usable to both termites and protozoa, when used as a sole diet. In conclusion, R. speratus is characteristic in digestibility of xylan with involvement of symbiotic xylanolytic protozoa in its hindgut.