Project

Life-history evolution of Termitomyces as a consequence of termite domestication

Fungi of the genus Termitomyces are exclusively cultivated by termites and completely dependent on them for survival and reproduction. The evolution of Termitomyces has been shaped by millions of years of ‘artificial selection’ by termites.

Within nests, termites harvest modified unripe mushrooms (nodules) for food. However, besides serving as a food source, these nodules also provide asexual gut-resistant spores that are the ‘seeds’ of new substrate. This within-nest propagation mode has two important consequences: (i) the mutualistic fungi undergo severe, recurrent bottlenecks, so that the fungus is likely to be in monoculture and (ii) the termites ‘artificially’ select for high spore and nodule production, because their fungal food source also provides the inoculum for the next harvest. We predict that this propagation scheme and growth regime has resulted in several evolutionary changes in Termitomyces life history, such as: i) Termitomyces colony growth is optimized for the naturally occurring spore density; ii) mycelial senescence has evolved as a trade off with maximized early reproduction and iii) the time of spore ripening has coevolved with the average nodule size at harvesting, which is different for different genera of fungus-growing termites. Within this theme several projects can be formulated to study life-history trait evolution of Termitomyces. Furthermore, the effect of genetic drift and selection on Termitomyces evolution can be simulated in in vitro experiments.

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Used skills:

Basic microbiological techniques and various molecular methods (such as PCR and sequence analysis). Statistical analysis.

Requirements:

Molecular and Evolutionary Ecology (GEN20304) and Genetic Analysis, Tools and Concepts (GEN30306) provide a good preparation.

Supervisors

Duur Aanen and Fons Debets

Reference:

D.K. Aanen. 2006. As you reap, so shall you sow: coupling of harvesting and inoculating stabilizes the mutualism between termites and fungi. Biol. Lett. (In press.)