Buggy

You do not find these wandering around, you shake them out of vegetation. Breaking plants in the jungle is the only route, and plant size matters more than anything else: the big ones pay out many times more often than grass or vines. Sweep a wide stretch of jungle floor with something that clears a lot of tiles per swing and the bugs come with it.

Of the three bugs that fall out of jungle plants this is the best bait and the one that shows up least, so most of what you collect will be the other two. Keep all of them anyway. The weaker ones are fine for ordinary fishing and you save this for crate runs.

Only so many jungle bugs can exist near you at once, so standing in one spot and grinding stops paying. Move along and clear fresh ground. And a Buggy Statue is useless as a bait farm, because anything a statue spawns puffs out of existence the moment you swing a net at it.