How do bristle worms reproduce?

[brokewithatank]

I recently started a refugeum and added some live rock to it. The fuge is attached to my sump for my 120 reef. I have never seen a bristle worm in my main tank and noticed there are a few on the live rock in the fuge. My question is this. How do bristle worms reproduce? Is there a danger that they can get into my main tank? They would have to work their way into the overflow from the fuge, then into the sump and then into the return to make it to the main tank. It is a CPR system fuge. Should I be worried about the bristle worms in the fuge or not?

Thanks.