That's a big planter for a seedling. It's hard to keep the soil watered but not too wet with a big planter. Next time, I'd recommend a smaller planter, like a plastic cup with drainage holes cut in the bottom.

I can't tell you what the bugs are, but if they bother you, get some diatomaceous earth from a pool supply shop, online, or nursery. Call around, most don't carry it.

It's made of microscopic sea shells, and a dusting on the top of the soil will cause bugs and larva crawling on the soil to be torn to pieces.

They don't get immune as with chemicals since it's physical injury to them.

The shells provide nutrients and silica to the plants, and it's organic too.