Ask-a-Dave's-Gardener: Do ants eat caterpillars and other stuff, 1 by HeatherJoy

HeatherJoy wrote:
We have a butterfly bush in our backyard that hasn't bloomed yet. There are ants all over it!! There are no aphids or other bugs but there are leaves that look like they've been eaten by a caterpillar. We are wondering if these ants are killing the caterpillars (we like butterflies) and if so, can we kill the ants without harming butterflies or caterpillars? I've included two pictures of the ants and two pictures of the "caterpillar chow marks"...are these holes/damage being made by caterpillars? Will the ants kill them? Any advice? We are in Sacramento, CA and these pictures were taken today. Thank you :-)