I've also called them roly-polies and pill bugs. They seem to have gotten into one of my outdoor pots, and now I've found them in a prenma microfolia I got from my bonsai club.
I've elected to leave the outdoor one alone, since winter is almost upon us and the pot is far larger than the plant needs. (I'ts a hibiscus I paid $5 for when a department store was selling all of its outdoor stock 50% off, and it's in a huge concrete thing I picked up off the side of the road.) But I wonder about the prenma. Do wood lice harm bonsai roots or not? Some people say they will and that I should immediately kill them all with insecticide, and some others say they only eat dead wood and don't do any real harm. What do you guys think?

Hi Hannah, Good to hear from you!

I searched Wikipedia for the woodlouse and this is what I found. There's bit about what it eats and the possible threat to young plants under the Ecology section. Hope this helps.

Here's what I found:
"The woodlouse is nocturnal and usually shuns the light. This led him to search for dark moist areas colonize it with several other individuals. It will be easily seen under leaves, under bark, in dead wood, or in rock crevices in cellars and in the horns of (mushrooms growing in deciduous forests at the foot of chestnut).
Power [edit]

The woodlouse is a détritiphage which feeds on dead plant matter in decomposition. It thus contributes to the recycling of dead and allows a more rapid return of nutrients in the soil. It can also deal with living plants, roots, fruits, etc.. "

It will be wise to change all substrate and spray neem oil on the roots.

Leslie wrote:

Hi Hannah, Good to hear from you!

I searched Wikipedia for the woodlouse and this is what I found. There's bit about what it eats and the possible threat to young plants under the Ecology section. Hope this helps.

Sorry Hannah...I forgot to include the link. Here it is:
en.wikipedia.org/wiki/Woodlouse

So it seems as though they are a bit of a pest, and should be dealt with accordingly, but aren't an immediate threat. I guess I'll have to repot it eventually, but for right now it seems to be fine. I'll do a cursory spray of insecticide though, just in case.

for me they are pest. I cut the some big brunch on my fig tree a temporary prunning and rain came that afternun the nxt day wood lose starting eating the expose weten cut wich cause a shallow barrow as the time comes, rain water start stuck on that hole creating decaying wood and the woodlose consumming it. The rain and woodlose makes my tree to have an unwanted ugly jin and...so i curve it in shape were rain water dont dump it.