Too late - I check the plant at lunch, and I could no longer find the caterpillar. I should have followed my instincts and brought the plant inside, as it is in a pot and could live in my art studio, which has a skylight and large windows.

He showed up again this morning, and so now I think I will bring the pot inside. Now there are two caterpillars, and so maybe it would be okay to leave the pot outdoors. What would you do? It's inside right now, but I can move it back at lunch.

I would not leave them unattended on the parsley inside your house. The caterpillar appears around full size so it might wander off to pupate at any time. Then you're searching your house for it.

This website has useful info. Simpler enclosures are just ziploc containers with parsley cuttings in them.

Raising BSTs

Yes, Parsley is one of their host plants and if it were me, I'd protect him/them if there is a chance of a predator getting them. This one looks like it's in one of the last instars and if so, it won't be long before it forms it's chrysalis. I have two late ones, too. One formed it's chrysalis on the lower area of a parsley stalk and the other one is still eating. Most likely both of mine will overwinter and not eclose until next spring as it is getting quite cold here (last two nights below freezing). I also have another one that has been here since mid summer and it looks like he is also going to overwinter. I think it's quite common for this variety of butterfly to do this.

I can't remember if these little guys do a lot of walking about when they're ready to form their chrysalis. Perhaps someone else can speak to this. If you keep them inside, one or both might leave the plant to seek out their special spot. They will most likely form green chrysalides, especially if they remain on the parsley, which will make it difficult to spot them on the plant. You will need to locate the chrysalides or be very careful when you harvest parsley, so you don't mistakenly damage them.

Thank you for protecting them.

Mary

Maybe I should put the plant on a stand, so that they don't walk off. I think I will leave the one pot inside, as it gets plenty of light and the plant was in a part of the yard where it was out in the open. I have another pot of parsley that is in a more protected spot, and I noticed two very small caterpillars on that today, but I will leave that pot outside.

I do not know about overwintering - we do not really have winter here - never a frost, and normally it does not get below 45° in the winter. Last winter was rather warm, and it only got below 50° a couple of times, but I think this winter will be colder and have lows in the 40s on the colder nights. I don't think temperature is an issue with this butterfly, however, since they live in colder climates than mine.

I will be very careful when harvesting the parsley, but I would rather than the butterflies than the parsley, although I think I can have both. I guess I should plant some more, since it does well here in the winter.

I am curious about whether they will wander off to form their chrysalis.

Thanks for the link - I will have to do some more research on raising these butterflies, as they are one of my all time favorites. The yellow swallowtails are fairly common here, but I think this might be a black version. What would an Eastern Swallowtail be doing in California?

Oops, I didn't think about your location. Yes, I suppose it's possible they could react differently to the weather in California. Maybe someone from your area will see this thread and comment. Happy you're going to keep the little guys inside.

Mary

You failed to mention you were in CA before. That means you have an anise swallowtail. Does not change how you raise them.

Raising anise swallowtails

Once those caterpillars are ready to pupate, they will likely find their way down your plant stand. You need a moat or an enclosure to keep them from wandering off.

Thank you for sharing your pictures and fun. Those of us who are in the colder regions of the world appreciate a chance to enjoy the benefits of your warmer weather. It was clear to me from your initial post that you were in a climate that remains warm year-round.

Martha

Lars, like Martha, I'm also enjoying experiencing the growth and development of your little cats through your photos. They look fat and healthy and I know will grow into lovely butterflies. The world would be quite bleak without these little flying jewels.

Mary

That's a Black Swalloetail. If you touch them, it will put out like a snake from above their heads. HE LOOKS BIG enough he may go pulpaany day now.

But what state are you?

I am in southern New Jersey and we've had a mild Fall so far. I have kept my Parsley plant outside but found a wandering parsley worm/caterpillar on my deck this morning. I put it on the plant but we are getting cold this week. If I want to save the parsley plant, I'll have to bring it inside but don't want any "wanderers" in the house. I can actually see the remains from one that did not make it :( I was surprised to see the butterflies hanging around so late but they were here not too long ago. Suggestions?

Do y'all think that they would lay eggs on my parsley? I was planning of hosting them in spring.

Well, i think you should put the caterpillar back on the deck. It might have been searching for a place to pupate. And parsley plants survive the winter.