Queen Butterfly Caterpillar

I'm trying to figure out what the larval host plants are for the different butterflies so I can have them in my garden to attract more butterflies. This is a Queen butterfly caterpillar munching on Jumete (Asclepias subulata) flower buds. Queens are related to Monarchs and the caterpillars look somewhat similar. Jumete is in the Milkweed plant family (Asclepiadaceae) and Monarchs like Milkweeds too. A couple of hours after taking this photo, I walked by the plant and the caterpillar was gone--maybe one of the birds ate it for breakfast.