How do dampwood termites extend their activities once established?

Dampwood termites are known for their unique behavior of infesting and extending their activities primarily by moving into sound and relatively dry wood. Once they establish a colony, these termites seek out additional wood sources to sustain their population. While they typically prefer damp, decaying wood, they are also capable of tunneling into drier wood, which can contribute to the structural damage of homes and buildings.

The ability to extend into drier wood is crucial for their survival as they may exhaust the resources available in their initial damp colony. This behavioral adaptation allows them to thrive even in less-than-ideal conditions, thus increasing the potential for damage.

Other options may suggest expanding their range or altering their environment, but the actual behavior of dampwood termites highlights their focus on infesting wood materials that support their growth and reproduction, which is accurately reflected in the correct answer.