Does this sign apply to all insects?
Yes, this is the general sign for "bug" or "insect." However, many specific bugs, like spiders, bees, or butterflies, have their own unique signs that you can learn as you build your vocabulary.
How do I show that there is more than one bug?
In ASL, you can indicate plural "bugs" by signing "bug" and then sweeping your hand slightly to the side or repeating the sign in different spaces to show a group. You can also add a sign like "many" before the noun.
Should I use my right or left hand?
You should use your dominant hand for this sign. If you are right-handed, use your right hand; if you are left-handed, use your left hand. Just be consistent!