Termite Damage
Termites attack anything containing celulose.

Wood attacked by subterranean termites (Left) generally has this distinctive feeding damage when viewed from the grain end.  Paper products such as the paper backing on the fiberglas insulation (Right) can also be attacked.

Shelter (Mud) Tubes -- One of the most common signs of termite attack.

Here, they are seen from inside a crawl space.  The blocks here are each 8" high.  This is a classic view.  The presence of these tubes does not necessarily mean extensive damage or even indicate a "live" infestation.  In order to determine whether the infestation is live, one simply breaks open the tube at any point and looks for termites.  A live infestation always has termites in the tubes.

You also sometimes see "Hanging" shelter tubes.  These occur in infestations that have been active for a long time in large beams.  The termites are building these tubes down toward the ground so that they have better access along the length of the beam.  Notice the mud caps protruding from the base of the beam (another sign of advanced infestation).  This floor joist will have to be replaced at considerable cost to the homeowner.

This picture shows termite shelter tubes hanging from the joists (freestanding) and indicates just how bad this can get. Note the tube in the center where the termites are building up from the ground to reach the hanging tunnel.  This house has "MAJOR" termite damage and it is obvious that the owner has not been in the crawlspace for many years.  There must have also been huge swarms (see below) in the house every year for many years and were neglected by the homeowner.  The structural damage here is certainly going to cost five figures and it may even be less expensive to tear the house down and rebuild it.

Swarms -- Most homeowners first notice termites when they swarm in their house.

This is an extremely bad case but illustrates the point.  The alatae (both sexes) emerge all at once and is hard to miss by the homeowner.

Same swarm, a few hours later.  The alatae have piled up on the carpet and will soon shed their wings.  If the homeowner missed the above swarm (maybe away on vacation), the pile of irridescent wings left here will be a good infestation indicator.

Other Termites -- Not often encountered in Kentucky, but you hear about them from time to time.

Alatae of the subterranean termite (Left),  Formosan termite (Center), Drywood termite (Right).  Note the black vs. red body, light vs. dark wings.