What do Formosan termites primarily utilize for moisture?

Formosan termites primarily utilize wood fungi for moisture because these fungi break down cellulose in wood, making it an excellent food source while also providing moisture that supports the termites' survival. Formosan termites thrive in environments where they can access decaying wood and the dampness associated with fungal growth. This moisture is crucial for their physical health and plays a significant role in their ability to digest cellulose efficiently.

The other options do not serve as primary moisture sources for Formosan termites. Concrete does not provide moisture; it is a barrier to their access to water. Air humidity is not specifically enough for their needs, as they require a more concentrated source of moisture. Water bodies are important for some other species of termites, but Formosan termites are more closely tied to decaying wood and the moisture retained by fungi within that wood structure.