Which wood-destroying beetle does not leave frass in its tunnels?

The Ambrosia Beetle is the correct answer because this beetle does not leave frass, which is the term used for the debris or droppings left by wood-boring insects. Ambrosia Beetles are unique in their feeding habits; they do not consume wood as many other wood-destroying beetles do. Instead, they introduce a fungus into the wood that serves as their food source. The larvae then feed on this fungus, which means that they do not leave behind wood particles or frass in their tunnels, making their presence less easily detectable compared to other wood-boring beetle species.

In contrast, other beetles, such as the Old House Borer and the Bostrichid Beetle, typically leave frass as they tunnel through the wood, as they are actively consuming the wood itself. The Dampwood Beetle also tends to leave behind frass due to its wood-eating activity. Thus, the distinctive feeding behavior of the Ambrosia Beetle is what sets it apart from the others in this context.