I was out whale watching (not much activity there) when I saw these two butterflies engaged in a mating ritual, I think. They have somewhat similar markings to monarch butterflies, though not as delineated. They get their name because the caterpillar feeds only on passion vines.

The Hawaiian monarch butterfly comes from the same stock as the mainland variety. It made its way to Hawaii in the mid 1800s, shortly after the milkweed plant (one of the Monarch’s host plants) was introduced. There’s a white variant that’s been seen on Oahu, but not on the Big Island as far as I know.