I'd bring them in, if you have time to raise them. Or bring in half. Their chances of survival are better protected from predators. But, predators need to eat too.

Martha

If you bring them in, you might just want to bring a few for one jar. All in one jar would be too much as they got older.

You can always raise them to their fourth instar or so and then release back to the milkweed. They have better odds of surviving the bigger and older they are.

I raise them to the 5th instar and release them, right after they molt and begin eating again. I like to release after dark or on a rainy day when the paper wasps are not flying. I find them to be their biggest predators up here.

John

A beautiful butterfly photo.