I opened by worm bin the other day and was surprised by a bunch of fruit flies and little buggles crawling around.
I discovered the little crawlers are mites. The ones I had in my bin are reddish and slow moving, which I learned are not predatory. They thrive in damp conditions (which I keep finding is the case in my bin!) So I'm not feeding as much, have added some dry soil, and am trying to keep my bin open for a while each day.
The fruit flies:
I've set up 2 traps like one I learned about from a juice bar owner a few years ago. I put some apple cider vinegar in a small mason jar with a drop of dish detergent, cover it with saran wrap with a small corner uncovered: