Hello! So I have a Fukien Tea Bonsai and i just noticed that it's home to some sort of spider. I was wondering if it's doing any harm, or could it help against pest from hurting my bonsai? It kinda looks just like a house spider...

It's that black thing curled up in front of the leaf (it's sleeping i believe) and he has a little web made there aswell! I though it was dead a few days ago and then knocked it off, but then i noticed it must of crawled back up the tree a day later. I won't kill it if it's not doing any harm.