wow, yes this guy is crazy... it doesn't say they feed on swamp milkweed, but it was, do you think that is bad, for instance; the west Virginia white butterfly feeding on garlic mustard vs it's host plant , and the cats die? would love to try to raise this, i have all the host plants on my farm here... I raise monarchs too

The dorsal horns might just provide a good defense against hungry birds or parasitoids that may be around, so if it can get past the toxic compounds in the milkweed, it might just make it. At times, adults do lay eggs on plants that are incompatible for larval development. Larvae also sometimes wander off to another plant if the one there on is not palatable, or if they feel threatened (by ants, for example). Time will tell. As you know, Monarch larvae love swamp milkweed, so these will be around in your area as well.

yes I raise monarchs, and have a swamp milkweed, tropical milkweed, swan milkweed and joe pye bed... it's great! thanks for the info