Christie, That is very interesting!
I recently lost all my bronze fennel to the heat again...I tried it in a raised bed in semi-shade & it still died! I recently found tiny cats on a couple of Zizia plants that I started from seeds. I only have a few leaves left so I've been offering them some rue. They have ignored the Zizia leaves but are eating the rue...thankfully! I've lost several rue plants as well to heat! Parsley & dill do well in the early spring but won't make it through the summers for me...even in the shade!
I had a friend that posted that she had BST eggs & cats on cilantro & I thought she was crazy but I understand that at least cilantro is in the same family!
I guess your BST ladies can't tell the difference between their host plants & other green leaves! LOL
Keep us posted!
Lila

My bronze fennel looks terrible but none of it has completely died. Lots of dried out looking foliage. I've been trying to keep it watered but we had too many triple digit days. I have quite a few rue plants too, at least a dozen, and the foliage on those looks more fresh. I haven't been finding any eggs or cats on that either.

The three new eggs I found on asparagus all hatched yesterday morning. This morning they had left the aparagus. There's one on the bronze fennel that I put in the container, and three on some rue, a total of four. lol They're all the same size so I don't know which one was the stowaway or how I missed it. I always inspect leaves very closely to look for tiny spiders. Maybe time for an eye exam.

Here's the first one. It emerged and was fluttering around in the container when I came home from shopping yesterday afternoon. Looks like a normal Black Swallowtail I guess. If it happened to be an Ozark Swallowtail, I don't think I would be able to tell the difference.

She's gorgeous!

I've never raised asparagus, and I don't know what plant family they're in, but I guess they're in the celery/carrot family that black swallowtails use.

Your butterfly looks just like female black swallowtails look here - again, she's a real beauty!

Sherry

Thank you Sherry!
Even the plants in my yard that have been getting supplemental water are drying up from our drought so I'm sure there must be a lot of dried up host plants in fields and wooded areas where the butterflies would normally find host plants. That might make asparagus look more appealing.

I witnessed a black swallowtail laying eggs all over my asparagus fronds. It surprised me, as well. That's interesting about the rutin. Is there any visual component to selecting a host plant? Because asparagus and fennel fronds certainly do LOOK alike.

That is definitely interesting about asparagus/rutin. I have had a terrible butterfly season - the *only* eggs I have found have been from several nurseries that I stalk, and the most eggs were on a group of asparagus plants. They do resemble fennel and dill, and I thought a 'mistake' was made.

Every female that I've had eclose this year has been taken out to my rue bushes to finish drying, with instructions to come back and lay some eggs! They're not listening :(

I thought my BST had lost her mind; I watched her as she fluttered around my neglected asparagus, weeks ago. I did try to rip it out, since it's not worth growing, but a few strands made it through and produced very tall foliage. I did find an egg, which I picked off and moved to my parsley. But, today I found 2 teeny tiny BST caterpillars on that asparagus! I'm going to leave them be and see if they do indeed eat the asparagus, and if it seems like they're lost, I will move to the parsley.

I found this threaf when searching for black swallowtail eggs on asparahusasparagus. I watxhed a female laui eggs and was able to collect tgree of them. Im putting the asparagus cuttings right in with some dull and will add zizia and parsley if they hatch.

I’ve had BST lay eggs in my asparagus for the past three years. I have a large dill patch and parsley on the other side of the yard where eggs are laid as well.

The BST caterpillars must eat the asparagus in first and second instar stage, because I’ve observed dozens grow on the plants for the last few years. However, I’ve never seen them past the second Instar stage. I don’t know if they stop eating and travel to the dill and parsley or if predators find them and eat them. It’s a mystery!

Or they died without travel and without predators. Bob, please protect, and feed asparagus to, a large number of them, to inform yourself and us.