If you want to be accurate, Spiders are NOT bugs nor Insect. They are called Arachnids. It goes on like this:
1. Kingdom: Animalia
2. Phylum: Arthropoda
3. Class: Arachnida
4. Order: Araneae
Bugs or Insects is differentiated by it's Class-level compared to Spider. While Spiders are Arachnida, Bugs and Insects are Insecta, with more variations on its Order-class. They have different body structure such as body segments, legs, antennae, etc. Therefore, Spiders are not Bugs nor Insects.
Please read and think of what you've typed in the forum because every time I read your comments, it is almost as if you're begging me to humiliate your intelligence by using (worthless) semantics to point out your piece.
I don't care what you think. If you think spiders and are bugs despite the stated fact, then that's fine. Do not insult my intelligence by pulling it into your level, I won't engage in semantics with you.
To the question of 'Then, to what level does the MC of Worm can control the insects? Is it up to Class-level, or Phylum-level?'
My answer would be: I don't give a fuck. It's not a scientific novel.