Adventures with the gold rim swallowtail

August 12, 2010

The Gold Rim Swallowtail (Battus polydamas) is one of just two butterflies that I know of that prefers the Dutchman's Pipe vine (Aristolochia glantea) to lay it's eggs. The other is. of course, the Pipevine Swallowtail.

The female lays tiny yellow eggs on the leaves or the stems of the plant. The dark brown caterpillars have thorns. In the last week alone, I've found one large caterpillar, one medium and bunches of very tiny, just hatched caterpillars.

I don't know where they go becuse sometimes I can find them right away and other times, not at all. Yet, they show up again the next day. I usually turn over all the leaves (gently) to look and that's how I found the largest caterpillar this morning. This afternoon? I can't find him.

My attempts to attract the Gold Rim Swallowtail began with having my husband build a trellis for the pipevine, a fast growing plant with not very attractive flowers. I don't have a picture right now, but if one of them does produce a flower this fall, I'll add it to the site.

I don't know how much Dave spent on lumber, but he built the trellis in about a day and a half. He loves to work with wood. We have a pipevine plant on either side of the trellis. This was done in the middle of July. Already the vine on the right side is starting to cover the top.

On the left is the finished project. On the right is one of the plants in place.

I filled the space underneath with white, and red pentas. In the background is yellow and pink purslane for groundcover.

Eighteen days later I noticed this gold rim swallowtail caterpillar. He is already big and lives down in the leaves of the plant, so I'm assuming the butterfly found the pipevine plants almost immediately and laid eggs in that area.

Aug. 10 and 11 -- the swallowtail laid several bunches of tiny eggs. And, when the caterpillars chew their way out, they are almost as tiny.

Aug. 11 - After hatching, the eggs remains are the first meal of the tiny caterpillars. After that they begin on the leaves. It doesn't matter how many leaves they destroy; with two plants on the trellis they'll have plenty and remember, this is one fast-growing plant.

Two pictures of the actual egg laying event. On the left you can see the position as she lays the eggs on a stem of the pipevine.

On the right, is how she looks from above. Her wings are close together and she is fluttering them rapidly in order to maintain her position.

Aug 11 - After laying her eggs on one of the rapidly growing stems, she hovers in space to check them out. After laying this particular batch of eggs, she flew around them for several minutes before going about her normal workday.

Aug 12 - Here you can see the size of the caterpillars as they grow. There are actually three in the grouping, but one is on the underside of the leaf. This has to be two hatches because of the difference in size. Life is not easy for a caterpillar. This one has been attacked, by what I just don't know. The pipevine is a poisonous plant and the caterpillar, pupa and butterfly are uneatable for a predator. But, somehow the caterpillars seem to disappear. My neighbor, who also has this plant for the butterflies, thinks that wasps are the culprit. For whatever reason, this caterpillar has definitely disappeared from the vine.

Aug. 14 - This caterpillar has survived the longest and is about one and one-fourth inches. It's getting easier to find him! You can see his growth day to day now.

On Aug. 20th, I found the first of 3 pupa on the vines. At right, one end is attached to the stem and the pupa is held up by threads that the caterpillar wrapped around the stem and itself. As I write this, it's been 9 days since their discovery and I've not noted any changes in them at all.

On the left, you can see the caterpillar skin that was shed during the process. Plus, I've just read that the ridged line going up and over the top of the pupa identifies it as a polydamas or Gold Rim Swallowtail. If it was the Pipevine Swallowtail pupa, that line would not be there.

Aug. 22 - two swallowtails visited today and left more eggs,usually 12 to 15 in a batch. This seems to happen two or three times a week.

Aug. 29 - 9:30 a.m. - The big caterpillar mentioned above has been eating his way to largeness!! Today he began the process to disolve the outer layer and reveal the pupa inside. I couldn't believe I actually caught him doing this. It is a very slow process wherein he appears to melt and drop away. Actually, his caterpillar casing is molting.

10:10 a.m. - He is getting smaller as time progresses and more of his casing disolves. Here he still has 4 appendages, dark brown on a lighter brown, still to disolve. At least 3 and possibly 4 others have already disappeared.

This would have been a great story if Mother Nature hadn't intervened. I had gone into the house to take a quick shower since I'd been weeding this morning and wanted to clean up. Because this looked like a process that would take a couple hours or more, I thought it was safe. Unfortunately, as I said, Mother Nature had other ideas.

10:25 a.m. - When I came back outside, I saw a yellow jacket wasp attacking my caterpillar. I shooed it away (gently!!), but it was already too late. The caterpillar had been mortally wounded and fell to the ground.

The wasp was still flying around, so I ran back into the house and got a can of wasp spray from the garage. One quick dose of that did the trick and he flew off.

I picked the caterpillar up and saw that the wasp had torn his skin is several areas and the green pupa that would have hardened and protected him for the next two weeks was exposed. He tried to hold onto the stem I put him on, but he couldn't. I laid him on a pipevine leaf on the ground and that's where he died at 10:35.