Données préliminaires sur l’écologie des Termites

Abstract

Nineteen species of termites have been found within the 1 Km2 reference quadrat of Fété Olé. Eight species (Bellicositermes bellicosus, Psammotermes hybostoma, Odontotermes smeathmani and five species of Trinervitermes) feed entirely upon grass material, whereas seven species are wood-eaters, three are fungus-growers and only three are humivorous. The distribution of the various species is undoubtedly influenced by soil conditions. Only four species are found in each of the four major micro-habitats (table II). The mounds of Bellicositermes bellicosus are conspicuous components of the local landscape. The density of living colonies reach 0.5/ha and the volume of earth used for mound-building averages 20-25 m3/ha. Population estimates for colonies of Bellicositermes bellicosus at various stages of growth are given in table IX. The standing crop biomass averages 4,750-5000, g/ha for Bellicositermes bellicosus and 750-900 g/ha for Trinervitermes trinervius (fresh weight). An estimate of the trophic impact of Bellicositermes bellicosus upon the grass cover has been attempted (table VIII). This species alone is able to consume at least 5.4 % of the grass produced in the quadrat as a whole. In the shallow depressions, where this termite is particularly abundant, it can consume up to 49.2 % of the grass produced. An attempt has been made to estimate the production of sexuals in two species : Bellicositermes bellicosus and Trinervitermes trinervius. The production of sexuals of these two species is respectively of 10,000 -20,000/ha (2,800 g/ha, fresh weight) and 15,000/ha (500 g/ha, fresh weight). Swarming takes place at different times of the year in different species : Rhino termitidae, Amitermitinae and Termitinae generally swarm at the beginning, and Nasutitermitinae at the end, of the rains.