Care:

Keep the nest temperature between 23°C and 26°C. In the wild, leafcutter ants are accustomed to an extremely stable underground temperature that fluctuates around 1°C year-round. The most important thing, however, is to measure the temperature where the fungus is located. Many people measure the temperature in the enclosure, and this is never accurate. You'll need a thermometer with a probe that you can place in the nest. This is the only accurate way to measure the ants' temperature.

Humidity. The humidity of your nest is crucial for the health of the colony. You should aim for a relative humidity as close to 100% as possible. Many sources will tell you that anything above 80% is fine. This is not the case. You should also measure this humidity directly where the mold is located. A distance of a few centimeters can reduce the accuracy of the humidity measurement by many percent. Keep in mind that any cold surface acts as a dehumidifier, converting water vapor in the air back into liquid water. This means that the front viewing window of your exhibit, which is normally the coldest part of your exhibit, will likely become covered in condensation, obstructing your view. Don't be tempted to lower the humidity to prevent this.