Agriculture is not unique to humans: some insect groups have also evolved this way of life. One such group is the fungus-farming termites, which cultivate fungi as food inside their nests. Such termites can be found in both rain forest and savannah habitats in the Old World tropics, from Africa to Asia. But as researchers report this week, a combination of DNA sequence analysis and computer modelling suggests that termite agriculture originated in the African rain forest, and gave rise to the many fungus-cultivating termite species alive today in various parts of the Old World.
The relationship between the termites and the cultivated fungus represents an impressive example of mutualistic symbiosis. The termites use chewed plant material, such as wood and dry grass, to feed the fungus and allow it to flourish, while the fungus converts otherwise indigestible plant material into nutrients the termites can utilize. Earlier work had shown that in the evolutionary past, a single, unreversed, transition to agriculture occurred in which termites domesticated a single lineage of fungi, represented today by the genus Termitomyces, a white rot fungus. These fungi are some of the few organisms that can digest the plant component lignin. Within the termite colonies, which can grow very large, the fungus grows on a special structure called the comb, which is maintained by the termites by the continual addition of new plant material.
Researchers Duur Aanen (University of Copenhagen) and Paul Eggleton (The Natural History Museum London), having sampled 58 colonies of fungus-cultivating termites (representing 49 species) in Senegal, Cameroon, Gabon, Kenya, South Africa, Madagascar, India, Sri Lanka, Thailand and Malaysian Bor
Contact: Heidi Hardman