Ecological studies on the symbiosis of termitomyces heim with Nigerian macrotermitinae

Abstract

The relationship between termites of the sub-family Macrotermitinae and the symbiotic Basidiomycete fungus Termitomyces was investigated. Fieldwork was carried out on several termite species at Mokwa in the Southern Guinea savanna vegetation zone of Nigeria. Termitomyces in nature and in culture is described. A selective medium was developed to facilitate isolation of Termitomyces. Optimum conditions of temperature and pH for Termitomyces cultures associated with different termite species were found to be 29°C and 5.2. The appearance, production of cultural mycotetes, blastospore size and germination of Termitomyces in culture was investigated. The cultures from different termite species could not be separated by these criteria. Methods were established for investigating the microbial ecology of Macrotermitinae nests. The fungal population and numbers and location of Termitomyces was detemined for Macrotermes bellicosuss, Macrotermes subhyalinus, Microtermmes species and for adjacent soils. Termitomyces was only found in the fungus comb. Other fungi were present there only as spores but when the comb was removed from the nest these grew rapidly. A substance was found in extracts of foodstore and termites preventing gemination of contaminant fungi. Termitomyces was present in the digestive tract of Microtermes foragers but only in very few Macrotermes bellicosus and Macrotermes subhyalinus foragers. The establishment of Termitomyces in new nests occurred by carriage of spores in the slate guts in Macrotermes bellicosus and Microtermes and probably from basidiospores in tho non-carriers. Termitomyces cultures produced polyphenol oxidases and cellulases but Termitomyces was unable to utilize starch, chitin and pectic substances. The nitrogen content of food, fungus comb and mycotetes was 0.28, 0.82 and 6.68% respectively. Termites consume the fungus comb and mycotetes and therefore Termitomycetes degrades nitrogen-poor food and provides the termites with a relatively nitrogen-rich diet.