We have been finding tiny piles of sawdust in closets and on our wooden entertainment center, but we have never seen any insects. The areas where we've seen the piles have myrtle wood on top of oak or fir. I had never noticed holes before but just today I saw tiny pin holes in the wood. What kind of insect is causing this, how do we get rid of it and could it be doing serious damage to the structure of our home? We've had perennial roof leaks that no one can really find the source of. I'm wondering if it could be related to these critters.
The sawdust could be from the emergence of small beetles called powderpost beetles. Existing powderpost beetle infestations are very difficult to control because the larvae are buried inside the wood for the majority of their lives (1 - several years). The best option is often to do nothing unless the infested wood is very valuable. Older wood is less likely to be re-infested by emerging beetles so the chances of new damage is less, but not zero.
The only effective treatment is whole house fumigation which can be extremely expensive. In some cases infested wood such as wood floors will be damaged to the point of replacement but often the infestation just "burns itself out". Myrtle wood is somewhat notorious for harbouring infestations of these beetles. Small wood items that show signs of emerging beetles can be treated by placing them in a freezer for a few days. BTW, this is probably not related to the roof leaks nor will it damage the structure. The beetles likely came in the myrtle wood.