@futurebird @PetraOleum i used to work on this in grad school - hard fungus to collect!
The fungus packs the hyphal swelling that it feeds to the ants with enzymes to degrade plant material. The ants eat the hyphal swellings, and then defacate on fresh plant material as they bring it into a nest. This is perhaps one reason why the fungus can't live alone now - it needs the ants to pre-treat the leaves with these enzymes in order to grow efficiently. Bizarre stuff!