CELLULOSE METABOLISM OF THE SYMBIOTIC PROTOZOA IN TERMITE, COPTOTERMES-FORMOSANUS-SHIRAKI (ISOPTERA, RHINOTERMITIDAE) .1. EFFECT OF DEGREE OF POLYMERIZATION OF CELLULOSE

To explain the role of three species of symbiotic protozoa in the cell ulose metabolism of termite, Coptotermes formosanus Shiraki, the effec t of the degree of polymerization (DP) of cellulose on changes of surv ivals, weights and protozoan fauna was examined when termite workers w ere forced to feed on test materials. The changes of survivals and wei ghts of workers clearly indicated that workers of C. formosanus could utilize wood meal, fibrous cellulose powder and low-molecular weight c elluloses (LCs) having different mean degree of polymerization (DPBAR = 27 and 17) as their nutrients. Feeding on LCs resulted in the drasti c disappearance of the largest protozoa, Pseudotrichonympha grassii Ko idzumi within four weeks, whereas the two smaller species, Holomastigo toides hartmanni Koidzumi and Spirotrichonympha leidyi Koidzumi proved to be alive even after 12 weeks. These results showed that P. grassii required relatively large DP of cellulose as nutrients, and that H. h artmanni and/or S. leidyi could supply the hosts' nutrient requirement s by decompositions of LCs to some extent with the absence of P. grass ii. They also suggested that the DP of cellulose was related closely t o the utilizations of cellulose by each protozoon species.