Tiny insects on new shelves - cause for concern?

I made some alcove shelves using a sliver of waney edged sycamore (i.e. with the bark left on so uneven front edge).


This was a couple of months ago, but in the last week or so I noticed a dark brown dust on the bedside cabinet beneath the shelves. I thought this was just some of the bark flaking off but today, when removing something from the shelves, I noticed a few tiny bugs/mites/bettles in the vicinity of the bark. They're almost too small for me to get a good look at - probably 1mm or less and dark in colour, with perhaps an orangey colour at the back. Its hard to see.



I've taken all the shelves outside and had a closer look and there are no signs of any holes and hardly any more bugs. There is an even layer of this dark brown dust beneath the bark though (which I've now mainly removed) potentially suggesting its just part of the tree rather than something that the insects have burrowed through.


Obviously I'd like these insects to be harmless but my first thought of wood + insects + indoors is not a good one! I'm not keen on treating the wood with chemicals if it isn't actually an issue and these are just some bugs that were living in the bark when the tree was cut down. Am planning to preserve the wood with beeswax and oil but wanted to go with 'natural' products and this has potentially thrown a spanner in the works.


Any ideas of what these could be? Would there always be holes with woodworm or is this just an obvious sign?