11.7 Gardening insects and fungi
Attine ants in Central and South America have a rather unusual and ancient relationship with a fungus generally called Leucocoprinus gongylophorus, in the family Lepiotaceae (Basidiomycota). The relationship is a mutualism which is thought to date back to about 45-65 million years ago. They actively inoculate their nest with the fungus and then cultivate it by providing it with pieces of leaves, pruning the hyphae and removing intruder fungi. As a reward the fungus produces special structures, called gongylidia; hyphal branches that have evolved to be eaten by ants. In Africa, some species of termite also maintain a ‘garden’ of fungi belonging to the genus Termitomyces (family Tricholomataceae, Basidiomycota). Nourished by the excrement of the insects, the fungus digests dead plant material brought back to the nest by the workers and provides more digestible food for the termites. We will describe these mutualisms in detail in Chapter 15 (CLICK HERE to view now), but we want to point out here that these are gardening insects, and just as we cultivate particular fungi for the food value of their fruit bodies, gardening insects cultivate fungi for the food value of the mycelium that results from its ability to digest plant remains.
Leaf cutter ants
We have a short (8 minute) segment of video from the PBS (Public Broadcasting Service) documentary “Evolutionary Arms Race” that illustrates the whole story of the coevolution of the leafcutter ants, the fungi on which they feed, and the bacteria they use to control the parasites that attack their garden.
This video is © 2001 WGBH Educational Foundation and Clear Blue Sky Productions, Inc.
Updated December 17, 2016