Why do drywood termites live entirely within wood?

The reasoning behind choosing that drywood termites can survive with little moisture is anchored in their biological adaptations. Drywood termites have evolved to thrive in environments where moisture levels are low, which allows them to inhabit the wood in structures without needing external moisture sources. This capability is significant, as it enables them to extract all the necessary moisture from the wood they consume, thereby allowing them to live and reproduce entirely within those wooden environments.

In contrast, while the preference for a dry environment influences their selection of habitats, it is their ability to survive with minimal moisture that fundamentally supports their life cycle. The special respiratory systems of these termites are tailored to their wood-dwelling lifestyle, but they are not the primary reason for their exclusive habitation within wood. Living exclusively on bark does not accurately characterize drywood termites, as they specifically extract nutrients from the heartwood and structural elements of wood rather than bark. This context helps clarify why the selected answer accurately describes a key aspect of drywood termite biology.