Also happening with Caterpillars this autumn, I'm attempting to raise a Red Spotted Purple or two. I eyed a female out in the yard laying eggs, curiously on two nonnatives, which the caterpillars seem to be eating. A Snowdrift Crab Apple but they're in the genus Malus so I'm doubt native or not really matters in that case. The other was a Japanese Weeping Cherry, but that's also a Prunus so maybe that doesn't matter as much? Still though I don't see Tiger Swallowtails or Silk Moths laying on the tree so I'm sure the native Black Cherry is the superior host plant. In the short amount of time I've had the sapling Black Cherry I can say I've already found way more caterpillars on it than the ornamental Weeping Cherry.
In the wild Red Spotted Purples always lay eggs towards the tip or ends
of leaves. Ideally it's the tip but I've seen some of the more spiky
edged host plants confuse them when laying and eggs are off center to
Funny enough EcoBeneficial interviewed Doug Tallamy about this topic. I have the same Lepidoptera species laying eggs on my Black Cherry sapling, but because I have a happy colony of Camponotus subbarbatus living in a log to that flower bed, my tree still has all its leaves! Every leaf on this plant has a nibble taken out which I would characterize as standard first instar caterpillar bites. But nothing beyond that! No branches stripped, no missing leaves, no half munched bites taken out of the leaves. Because I have this ant colony foraging on the tree, the caterpillars never make it beyond the first or second instar. Even the Red Spotted Purples don't seem to live long enough to make their first poo stick.
A complication with keeping this species in captivity is that they over winter in the caterpillar stage. In the wild they spin silk around a leaf or two to build a "shed" that they nestle into until the tree leafs out again next spring. (Perhaps consuming the flowers in the case of apple trees?)
So a friend suggested to me to keep them in the fridge when all the leaves fall of the tree. Hopefully that will be enough get them to survive the winter and I can continue to photograph their life cycle next spring.