Hello everyone, my apple bonsai recently got these small insects which crawl around my apple bonsai. Are these harmful to my tree? Do I need to remove them. Also this same apple bonsai has many ants crawling on the soil and on it. Are these harmful?

Can you share a photo?

I meant black insects and I have attached a photo. I think they are aphids.

That looks like soil mites to me. Are they on the tree as well?

Only some are on the tree

I would say soil mites then. No direct threat to the tree, but a sign that the soil may be too heavy on organics and kept too wet.