Actually, regarding the tarantula and scorpion, you don't have to worry about them biting/stinging you if you don't have your net.

The way they're programmed is that, if they spot you, and you're not holding a net, they will automatically run away. They only come toward you if they spot you holding a net, and you're not in the sneaking position.
One time, I walked out of Re-Tail and there was a tarantula right there. It saw me and immediately ran into the pond... And at the same time I pulled my net out. I didn't get into the sneaking position, and it didn't actually land in the water yet, so when my net was pulled out, it immediately ran out of the pond and bit me! DX So yeah, they will run away if you don't have your net out.
But bees... Yeah with bees you're screwed if you don't have your net, LOL!