The XVIIIth (New) International Congress of Zoology

Le XVIIIème (Nouveau) Congrès International de Zoologie

Termites, particularly abundant in humid tropical forests, absorb 6 to 7 tons of organic matter per year and per hectare, which corresponds to nearly 50 % of the vegetal matter falling down on the soil. Such an important role in the decomposition of organic matter is due to the fact that these insects harbor numerous symbiotic microorganisms in their gut: protozoa, bacteria, actinomycetes, mushrooms. They live in aeroby or anaeroby according to the species, and are specialized in degradation processes.

In lower Termites a very great number of protozoa and bacteria are found in the posterior intestine, while in the higher Termites, only a great variety of bacteria are present. In Macrotermitinae, an original symbiosis is observed with a basidiomycete mushroom cultivated by the insects. The vegetal matter is first degraded by the mushroom, and secondly by the Termites.

The study of 16S RNA and ITS (Internal Transcribed Spacers) of the different gut symbiotes allows us to determine the relative importance of taxonomy and diet of the host upon the composition of bacterial communities, in order to consider the hypothesis of a coevolution termites/symbiotes.