Insect Spawners Outside of Granite Falls.

I dont know how it works but I am wondering from all that I have gleaned by reading and digging through threads if it has something to do with the lot type itself that makes a persistent call to spawn specific obj IDs at random locations - and the only place that is doing that is Granite Falls - so without a "controller" to make a persistent call to spawn the insects they just do what they are supposed to, spawn then despawn after X amount of time or until harvested.