Originally posted by Anaxi:

I think it suggests dvergers might be responsible for the mistlands creatures they might have dig too deep

They were at least in the middle of mining when something made them abruptly leave, letting seekers move in. I don't think there can be any other explanation to abandoning tools in that way, given their semi-permanent outposts and fairly well cleaned up abandoned digsites. There seems to be no runestones to indicate the origin or explanation of any kind for seekers, so it's possible the insects are relatively newcomers in Valheim, at least aboveground. Even the inscription outside of citadel seems to be of dvergr origin instead of a viking type runestone, so they have at least some history.