The Longevity of Colonies of Fungus-Growing Termites and the Stability of the Symbiosis
Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
Author to whom correspondence should be addressed.
Received: 15 June 2020 / Revised: 8 August 2020 / Accepted: 10 August 2020 / Published: 13 August 2020
Fungus-growing termites cultivate monocultures of a specific fungi (of a genus called Termitomyces) for food in their colony, analogously to human farmers growing crops. The termites forage for dead plant material in the environment, bring this into the mound and provide it to the fungus as a growth substrate. After fungal growth, the termites use the mixture of fungus and degraded plant material and also the asexual spores produced by the fungus as food. They also use the spores to inoculate new fungus gardens. The termite-fungus symbiosis is obligatory for both partners, the termites provide growth substrate and a protected growth environment for the fungi in exchange for a nitrogen-rich food source. Termites and fungi have been partners for more than 30 million years and although the symbiosis looks harmonious, the partners have some hidden conflicts about reproduction and resource investment. These conflicts raise questions on how the symbiosis apparently has remained stable for such a long time. We summarize our current understanding on the short-term stability of a single generation of termites, and also the long-term stability of the symbiosis across multiple generations. We identify unsolved questions in the field and suggest possible avenues to address these questions.