When examining subterranean termite damage, which statement is true?

The correct statement is that subterranean termites tend to follow the grain of the wood when they damage it. This behavior is primarily due to their feeding habits; they seek out the softer, more nutritious parts of the wood that align with the grain, which makes their damage less visible and more challenging to identify.

This tendency contributes to the unique patterns of damage that can occur, often leading to long, narrow tunnels that run along the grain rather than across it, which might not present obvious external signs of infestation.

In contrast, the other options indicate misconceptions about subterranean termite behaviors. For example, they do not always leave visible holes, as their tunneling can create damage that is hidden beneath the surface. Additionally, they do not create dust piles, which is more characteristic of drywood termites that leave behind frass (wood dust). Finally, subterranean termites are not easy to spot because they often operate within the wood and soil, further obscured by the materials around them.