Recently, when inspecting my garden, I found 2 itty bitty butterfly larva, caterpillars, on some volunteer dill. I was very excited, because I love butterflies and it makes me very happy and proud to keep a garden that is wildlife friendly.
I knew that the butterfly larva I found was an Anise Swallowtail, or Papilio zelicaon, because it was on dill. Each species of butterfly has their own host plant species, which is a whole other post in itself, but the swallowtail here uses plants in the carrot family, including carrot, dill, parsley and fennel. I had also seen the beautiful yellow and black creature flittering around this bed the week earlier.
I debated on if I should just let them be, or if I should bring the larva inside and raise to a butterfly. After considering all the factors, like environment and bugs or birds that might eat the butterfly larva, I decided raising it inside would give it a much higher chance of survival.
The larva I found had recently hatched, they look a bit like bird poop- a brilliant camouflaging adaptation. They stay on that host plant, eating and growing and pooping (which is called frass, in case you were wondering), then repeat, and repeat….and repeat. The exciting life of a butterfly larva!
I cut the fronds of dill that the caterpillars were on, and gently placed them in a half-gallon mason jar, with my sprouting screen on top. In an ideal situation, I would have a large screened bird cage to act as my butterfly cage, but alas, didn’t have anything like that set up. A bucket or an aquarium with a fine-mesh screened top would have also worked. Regardless of the container, it should be well ventilated in order to prevent mold, but covered to prevent wandering caterpillars. Excessive heat can kill caterpillars and pupa, so I avoided direct sunlight and set my jar on my North facing kitchen windowsill.
Caterpillars have their skeleton on the outside, called an exoskeloton. As it eats, it grows, and will molt. Most will usually molt 4 or 5 times before turning into chrysalises. After its first molt, it changes into a more visible green and yellow stripes. A telltale sign that its about to molt is that the caterpillar stops eating for about a day, and remains where it is on the plant. They are very vulnurable at this stage, and should not be moved or touched. I was honestly a bit scared at how fast these butterfly larva grew. I had visions of coming into the kitchen and to find it took over the room, not unlike Jubba the Hut, and bellowing “feed me Seymour!”
I cut new fennel or dill fronds daily, and added to the jar. Once they crawled over to the new food, I would remove the old. A few times, I would move the caterpillars (either attached to the plant materials or let crawl on my hand), into a clean jar so I could clean out the frass. After 15 days, the larva stopped eating, then stopped moving, and appeared to be drying out. They were ready to enter their next phase of metamorphosis.
When the butterfly larva is ready to pupate, it often crawls away from the food plant for its next life stage. I wasn’t ready for pupation to happen so fast, so I hadn’t given them any additional sticks or cubbies to go onto. My larva formed their chrysalis right on the fennel stems they were eating.
Different butterfly species pupate in different ways. Some hang from a ‘J’ position, with their head down. Swallowtails pupate head up and spin a girdle of silk to hold themselves in place. A few days into the pupation (is that word?), the fennel started to wilt, and the chrysalises were starting to angle down. I was really concerned that would affect their transformation, so I very carefully cut out the section of fennel around them, ensuring I didn’t cut the silken threads, and used twist ties to attach the fennel section to a stick, then put the sticks back in the jar. This helped them stayed upright. They remained as chrysalis for 15 days.
During the pupa stage, phenomenal changes take place inside the chrysalis. First, the contents of the butterfly larva are broken down into a viscous substance. Meanwhile, the cells of the butterfly are activated and gradually the wings, head, and other parts develop. People say that human birth is a miracle, but a butterfly literally starts as a worm, turns into goo, then comes out as a beautiful gossamer winged creature. I think that’s a damn miracle!
Most butterflies emerge from the pupa stage early in the morning, with the wings folded and crumpled. They then pump their wings multiple times to start blood flow, and their wings will assume full size. They then rest, holding the wings apart to so they can dry. The first butterfly emerged from the chrysalis before I woke up, and was hanging from the screen lid ready to go. I carefully opened the jar and let it crawl out onto some bachelor buttons.
Butterflies will usually not fly unless the sun is out. Scientists think they may need the sun to warm them up, and many believe the butterflies use the sun for orientation and to avoid storms. The morning this one decided to emerge was cloudy and cold. It hung from the bachelor buttons for several hours, until the sun came out. I missed it’s first flight; it was gone when I went back to check on it.
The next morning, the second butterfly had emerged. This one had just come out from its chrysalis; it was on its stick and its wings were floppy, soft and weak. I took this one to the same place, and let it crawl over my hand to reach the flowers. It was sunny that day, and with the sun warming it wings, it departed much sooner. I watched for about 40 minutes, but had to go to work; sadly, I also missed its first flight.
That afternoon, I saw swallowtails flying around, up in the sky and fluttering down closer to the garden. Whether these were my butterfly friends, or others, I do not know. But just yesterday, I saw one flittering over my bronze fennel, and I later spotted a few eggs. I’ll check back in a week to see if I can find any caterpillars, and the cycle will start again!