Fungus-farming termites can protect their crop by confining weeds with fungistatic soil boluses.

Abstract

The symbiotic agriculture of fungus-farming termites can collapse if they fail to prevent invading weeds. Previous studies suggest a role for symbiotic fungistatic microbes in bringing about weed control. However, how termites employ these microbes to suppress fungal weeds without affecting the fungal cultivar remains unknown. We show that the fungus-farming termite <i>Odontotermes obesus</i> uses specific behaviors to remove, isolate, and suppress the growth of the fungal weed <i>Pseudoxylaria</i>, primarily by encasing it with soil boluses containing fungistatic microbes. These behaviors efficiently suppress the weed without affecting the crop. This integration of specific behaviors with termite-derived microbes appears to be the proximate mechanism of how microbes are topically used by termites to confine the weed while keeping the crop unaffected.