What Insect Leaves Sawdust on the Floor?

By Chris Williams on November 5, 2015.

Do termites or ants transport wood shavings? On a couple of occasions when I’ve gone down to the basement to do laundry, I’ve seen little piles of what looks like sawdust in a back corner of the laundry room. I’ve swept it up and it reappears. I’ve never seen any insects and I don’t see any kind of nest or wood damage there.

E. F., Stowe, MA

Termites don’t make or transport wood shavings since they eat the wood rather than just excavating it. Various wood-boring beetles will pack their galleries in the wood with digested wood particles. These particles, called “frass” and looking more like powder than sawdust, often filter out of their nests through exit holes in the wood. Some ants do tunnel in wood and will push bits of wood, along with other debris, out of their nests. The insect most likely to leave what look like sawdust piles is the carpenter ant (see Sawdust Piles Could Mean Carpenter Ants).

Carpenter Ants Leave “Dump Piles” Behind

Carpenter ants don’t eat wood but they use their jaws to tear wood pieces out when they are creating their galleries inside. They are very fastidious ants and like to keep clean galleries so they are constantly pushing accumulated debris out of their living space. They cut little slits in the wood that they use as “dump” sites. Below these slits, you might find a little pile that looks like sawdust. If you look at a carpenter ant’s dump pile under magnification, you will see that it is made up of wood shavings plus insect parts, dead ants, bits of seeds, and maybe bits of soil or insulation (see What’s in a Carpenter Ant “Dump Pile”).

If the sawdust is from a wood-boring insect, the infested wood should be directly above. However, you usually cannot see a carpenter ant nest or carpenter ant damage by looking at the surface of the wood. There is usually no external evidence that carpenter ants are nesting inside other than the slit-like openings. But if the nest site is probed with a screwdriver, it should easily break through into the galleries.

A basement laundry room is a very typical place to find carpenter ants nesting. They like high humidity and damp wood. Carpenter ant infestations often begin in wood that has been softened by water damage due to a plumbing or roof leak (see Carpenter Ants Prefer Damp Wood).

My advice to you is to give Colonial Pest a call and have our technicians inspect your home for evidence of carpenter ants or other wood pests. In some cases, the sawdust turns out not to be from insects at all and you can then rest easier.



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