Monarchs, Soldiers, and Queens

Gee, I just noticed that i have all 3 of these caterpillars on the same Asclepias c. bush. I don't know if this has been happening all years or is unique to this year. I've never noticed all three on one bush before, or even all three at the same time even on different bushes. Is this common and i've just never noticed before? Or is this fairly rare in your experiences?

I think it has to do with the nature of competition , I have seen Cabbage white and Buckeye and red Admirals all eat the same food as larvae , not suppose to happen , but that is something I have seen , the more you have , the more variation in what the larvae will eat occurs .
I guess they all like to fight ,lol Something you don't usually think of about Butterflies ..
That and they make good poison and ink .. grim thought ,,lol