Well, I'm not too sure that these butterflies are native to this area. I'm near Palm Springs in the California desert, if it weren't for man coming here with water and grass and tropical plants it would be only desert creatures that live here. That said, I am rather ambivalent about the insect world. I know that most of them are necessary but I'm not excited about being up close and personal with them. Some though, I'd eradicate without a thought. I've often dreamed I could send all mosquitoes and spiders to mars, just suck them all up and away.
Mostly I go by my rule that if they stay outside in their own area they can live, if they come inside into my area, they die. That's why I still haven't sprayed the passion flower, the butterfly really is outside in its world so I can't quite bring myself to kill it. The larvae though, squish!
As for only planting native plants, I am pretty disgusted with most of the rabid advocates of that. They took a beautiful grass field on the Bay in San Francisco, used by tons of city residents to walk, run, exercise their dogs, do tai chi, a million uses to the citizens of an urban area. It was busy every day of the year, it gave everyone in the city, rich or poor, a chance to enjoy the beauty of the Bay. Under the mantra of returning it to its natural state, they turned it into a swamp that may be natural but that no one can use. In an urban area, I think the needs of the humans outweigh the urge to return things to what they were. It also pisses me off to watch them go through and cut down beautiful shade trees in parks because they are not natural to the area. I think they are obsessive people with more concern for being right than for the world around them.