The Accidental Lepidopterist: Monarch Butterfly Edition

Mid-August and my garden is a sandy strip of nothing-going-on. We've had weeks of 90s and oppressive humidity, and the stubs of golden alexander and parsley left by the Swallowtails are struggling to grow back. Yet I keep finding fresh eggs and caterpillars on them! Off to the nursery we went to find host plants. The herbs were wiped out so I headed for the clearance tables hoping to get lucky. There was nothing for Swallowtails but I found a table full of Tropical Milkweed (Asclepias curassavica) for $2.09. It was buy 2 get 1 but A.curassavica isn't native, so I picked a small 2 1/2" pot that, once home, totally surprised me with two Monarch butterfly eggs. I scrambled online to learn as much as I could as fast as I could. I basically had their four days as an egg to prepare.

The first thing I learned was that eggs laid after mid-August comprise the 5th generation of the year, the one that makes the incredible journey southward to overwintering grounds. Recently listed as endangered, I felt doubly pressured to ensure their survival.*

Here is a picture of a fresh Monarch butterflyegg. When mature, the egg doesn't turn solid black like a swallowtail's.
Only the tip does, unless it's been parasitized by Trichogramma wasps.

Day 1 as caterpillars. I have to say, raising Monarchs is very different from raising Black Swallowtails. The method is the same (feed them their host plant, enable them to pupate, release a butterfly) but the experience is at a different pace and the details – the clues that tell you what to do next – are all different. 

To begin, newly hatched Monarch caterpillars are impossibly small, and it's frustrating trying to see if anything is happening. Turns out it isn't much, and they are completely boring at first.

Do you see both Monarch caterpillars?

Day 3 as caterpillars. They finally molted and wear black stripes, making them a little easier to find but I still needed a magnifying glass to find them. That's how I noticed little brown spots on the undersides of the leaves. Rust is a fungal plant disease that is host specific (won't jump to other plants) and doesn't harm the caterpillars. It is less of a problem for plants when moisture is managed properly. Next year I will look for a rust resistant variety but it would help if I knew what I had to start. I'm fairly certain the nursery mislabeled the plant I bought. Orange blossoms, fine hairs on the small leaves and stems, this narrow-leafed milkweed is most likely Butterfly Weed (A.tuberosa). Native to eastern and southwestern North America, I kind of wish I had bought three.

Swallowtails neatly eat entire leaves and stems but 2nd instar Monarch caterpillars need to avoid releasing the sticky white sap milkweed is known for. At their size it can glue their mouth parts shut. The leaf above is a good example of their skeletonizing method of eating. 

Day 5 as caterpillars. Still a second (of five) instar. A terrific reference to determine which instar your caterpillar is, is A Field Guide to Monarch Caterpillars (Danausplexippus) by Karen Oberhauser and Kristen Kuda.

Day 6 as caterpillars. With yellow stripes and tentacle nubs, they're finally starting to look like Monarch caterpillars.

Half a centimeter in the morning.

Doubled in length in one day!

Day 7: Third instar caterpillars are less wasteful but still won't eat the central leaf vein. One site I referenced said they will snip the vein to stop the flow of sap. Then they can eat all of the leaf after the snip. Mine just left unsightly midribs.

Rather than skeletonizing, week old caterpillars eat more leaf but not the midrib.

Day 8: Through the 3rd instar, two sprigs of butterfly weed has been enough for both caterpillars. This 4th instar is eating full leaves, including the midrib. Milkweed sap is full of the toxins that make Monarch caterpillars mildly poisonous to predators.

Just like Instagram, I'm experiencing upside down posting with Blogger. 🤷🏽

Older caterpillars will eat slices of cucumber, zucchini or butternut squash. You can also offer watermelon rind but feed them these alternatives only in a pinch.†

Eating so much more, I began to really wish I'd bought three plants. Several sources said a single caterpillar eats an entire plant so I did the newbie panic thing of driving from nursery to nursery looking for milkweed plants, only to find none. Or a sad excuse for a plant, merely sticks and leaf remnants complete with more eggs or caterpillars. Already the accidental lepidopterist, I didn't need to buy more problems; I just needed food.

Day 10:

At <3cm, not the "huge, finger thick" caterpillar we often hear about.

Day 13: As it turned out, I panicked for nothing. They abruptly stopped eating and shunned the food they had no matter how many leaves I placed them on. Monarch caterpillars do not do a purge, the telltale sign that a Swallowtail is ready to pupate. Nor do they go on a walkabout like Swallowtails. I had to take the refusal to eat as the sign and left them to do their thing, what ever it might be. After a few hours, they'd taken the j-formation side-by-side.

Hanging in J-formation, opposite to Swallowtails which suspend themselves head up, feet down.

Day 14:

Fifth instar Monarch caterpillar, ready to begin the final molt.

Like the Swallowtail, they spend a full day in the pre-pupal position, not moving, and there are indicators that the final molt is imminent. When you see the caterpillar straightening out and tentacles go limp, it is ready to begin the final molt to chrysalis.

Dorsal view of the final molt to become a monarch chrysalis.

Day 15:

1 day old chrysalis, wing veins already visible

Day 21: In the evening, they turned really dark. I am beginning to think all butterflies time it so they eclose early in the morning, to warm as the sun rises. A few hours in the sun's warmth helps their wings dry and harden.

Late night after 8 days as chrysalids, the famous orange and black wings clearly visible.

Day 22: As with our Swallowtails, we awoke to find an already eclosed butterfly still clinging to it's chrysalis shell, its sibling ready to burst out of its own. 

Good morning 9-day old monarch chrysalis and brand new butterfly!

I don't know if it is just the migratory generation that does this because they need extra strong flight muscles for the journey to Mexico, but ours beat their wings pretty regularly and slowly, giving us ample opportunity to determine their sex. These are both males.

Monarch wings are translucent. The stripes visible when the wings are folded are the same as those when their wings are spread open. This is different from swallowtails, whose wing spots in open and closed positions are different and you can only tell the sex when they're open.

The wings being translucent surprised me.

The outlook was for rain (as it often is here) so we held them overnight. In the morning, they could see the outdoors just on the other side of the mesh and were eager to get out. So eager that there was no placing them on a flower for a beauty shot, like I do with our Swallowtails. The instant we brought the hamper out, they flew out the opening, up into the forest canopy, and thus began their incredible journey to Mexico.

Butterfly Pool Results

Early in the morning, the side by side chrysalides no longer looked like twins. After 9 days as a chrysalis, the first to pupate (left) will be the first to emerge as a butterfly.

Note the color change.

A side view of the mature chrysalis shows the butterfly inside is arching, putting pressure against the outer skin.

Translucent = will eclose very soon.

The changes happen quick. We went for a pre-breakfast walk and missed the butterfly coming out of the chrysalis. And while I was making an afternoon smoothie, I missed a second butterfly emerge!

The bottom butterfly's wings are still wet and floppy.

When they first emerge, their wings are crumpled from being crammed in the chrysalis. The butterfly stretches and strengthens its wing muscles by slowing moving its wings. They quickly expand, dry and harden. 

A new butterfly likes something to climb up. I'd forgotten that they purge after eclosing. No solids like the last stage as a caterpillar, just a cloudy liquid.

I always try to set new butterflies on a flower. They don't need nectar yet, but I hope it helps them identify our yard as a good food source so they come back.

Still early enough that some morning glories are still available for offer.

Warmed by the sun, wings fully hardened, I think the butterfly must complete its purge before taking flight.

Finally, a dorsal view! This one's a male.

Another male. Compare their spots and you'll see that their patterns are unique.

Our third chrysalis turned out to be male as well. All three were in chrysalis form for nine days.

I wish one would've been a female so I could show you the difference in appearance. You have to look at their top side, which can take patience since they spend more time folded up than flat. When you finally glimpse of the dorsal view, look for the amount of blue. Males don't have a lot of blue. Females have more blue (which displaces the yellow). I found three more caterpillars on the parsley, so I'm still hoping for a female to show you soon.

Went looking for bees but found this instead.

The little garden space I asked for your help designing includes dill, parsley and Golden Alexander, all host plants for Swallowtail butterflies. Our backyard is so small, the entire potager is literally three steps out my kitchen door – a giant glass slider – so that's how I happened to see a butterfly laying eggs.

Small carpenter bee (Ceratina) foraging on dill weed. 07/22/2022

Do you see the butterfly egg? I didn't see it until I was going through my bee photos. I know this is a Ceratina because it has a small yellow mark on its face, not visable in the photo.
 

3rd instar caterpillar on Italian parsley. 07/30/2022

After finding a caterpillar in the jaws of a spider, I brought every caterpillar I could find inside and set them up with Oui jars like I did in 2019. This time, though, we had to go out-of-town for three days so instead of a daily top up, I had to guess how much food they needed. Turns out not much, just a few sprigs each.

5th instar caterpillar on Golden Alexander, which is native to the eastern US. 08/05/2022

We left with four 3rd instar caterpillars and returned to find three 5th instar caterpillars. It seems the natural mortality rate is high. This time they're the green variation.

Prepupa showing signs of final molt, small cracks in the cuticle (the lining of the trachea tubes are being pulled out of the spiracle openings) and loss of color. 08/07/2022

Attached to the inside corner of popup hamper, I could only get a dorsal view video but I'm just elated that we got to see it happen!

The transformation from prepupa to chrysalis took about 6 minutes, the last 3 being a whole bunch of wiggling until the shed skin fell to the floor. 

Swallowtail chrysalis color-matched to its environment. 08/07/2022

We've got three chrysalides in the hamper, and I'll post an update when they emerge. The Internet says anywhere from 7-20+ days. How about a Butterfly Pool? I think Monday the 15th and there will be 2 males and 1 female. What are your guesses?

Raising Black Swallowtail Butterflies, Part II

A Tail of Two Caterpillars

Picking up where we left off, the two caterpillars had been given a large potted plant to feed on, set in my honey-straining bucket. I showed you the first chrysalis, attached to some fennel.

The bottom half of my butterfly habitat. 7/25/19

One thing I forgot to mention is the size change from caterpillar to chrysalis. It shocked me. Here's a photo of the two caterpillars so you can see how much smaller the girdled, ready-to-pupate caterpillar is compared to the caterpillar that is still actively feeding. 

Not a matter of depth perception. The inverted-J caterpillar is much smaller than its sibling. 7/27/19

After head-butting its girdled sibling, causing it to jerk defensively, the second caterpillar ate a bunch, purged a blob of semi-digested parsley, then went for its walkabout. It left the potted plant and went up into the hamper, where I'd placed several long flower stalks for them to choose from.

Second caterpillar girdled to a day lily flower stalk. 7/28/19

It too formed its chrysalis during the middle of the night so, again, I didn't get any pictures of it happening.

The second chrysalis. 7/29/19

There's quite a bit of detail and texture, so be sure to click/tap on the photo and zoom in. Once they go into chrysalis, the waiting game starts. I read that they emerge in 9-11 days but anecdotally I heard as short as a week. I'm sure that day/night temps and day length play a role, so I figured mine being indoors would emerge on the later end of the spectrum. Of course, that didn't stop me from checking incessantly.

Caterpillar 1

Pretty much nothing happened until a day or two before the butterfly emerged. True to itself, the first caterpillar to pupate was the first to show a subtle change. Without my macro lens, I might've thought the slight darkening was just lighting conditions, a shadow cast on it.

11 days as a chrysalis. The top side is grayish-green instead of bright green.

Early in the morning of day 12, I found the butterfly emerged and flexing its flight muscles. Its wings were already dry and fully expanded. Having seen its plain Jane, black and yellow mother, I was really happy to see all this color. The neighborhood females should find him quite attractive.

The caterpillar, I mean, butterfly pooped on the fennel stalk. The meconium ran down to the girdle.

I had to wait for what seemed like forever to see the top view, where you can determine the sex of the butterfly. From the dorsal view, males have more yellow than blue, and females have more blue than yellow.

I find it fascinating that the underside of the wing looks entirely different from the topside. It's so thin, how can that be?

It might've been because I was sticking a phone in his face, but he took a misstep and fell between the potted plant and bucket. He couldn't climb up the plastic, so I stuck my hand in and he walked right onto it.

33 days from egg to butterfly. This is a male. Females have more blue and a smaller yellow upper band.

As newly-emerged mason bees often do (or don't?), butterflies don't walk onto the flower you show it. They tease you by touching it, then zip-bang they're into the wind. I barely got to see him fly, he flew away so fast. I hope he imprinted on my garden and comes back.

Caterpillar 2

Day 17 and I am starting to wonder if it's a dud but hoping it's just going to overwinter as a chrysalis. Be sure to add my blog to your feedburner (I use Feedly) so you don't miss a post about it emerging in, oh I don't know, April?

The second chrysalis showing no signs of change. 8/14/19

Raising Black Swallowtail Butterflies, Part I

Despite baiting my top bar hive with an expired queen, ready-to-use combs, and repeatedly applying lemongrass essential oil, I was not successful in luring a swarm to move in and the beehive remains empty. But other buggy things are going on in the backyard that I thought you'd enjoy alongside me.

I started posting a #macromonday challenge on Instagram, where I post a photo of a flower bud and ask for your best guess at what flower it is. It just so happened that my parsley was in bud, and I saw something weird on it.

Can you spot the tiny yellow egg? 7/3/19

Black swallowtail butterflies nectar on many flowering plants but the female lays eggs only on plants the larvae can eat. Their host plants include dill, fennel, carrot… plants in the Apiaceae or Umbelliferae family. Over the course of a few days, I found a total of six eggs on one parsley plant. The photo below shows three eggs of different maturity. (Clicking on any photo will bring up an enlarged & enlargeable version.)

The egg turns almost black when close to hatching.  7/7/19

When hosts plants are not abundant, the mother butterfly will lay multiple eggs on one plant. With plentiful plants, she'll lay fewer eggs per plant. Being spread out increases the young's chances of survival. It's estimated that only 1% of eggs laid survive to become a butterfly. I planned to leave them alone, outside, and just let nature happen. But over the next few days some other insects came to call the parsley home. An ambush bug and a spider were particularly concerning.

Female black swallowtail nectaring on oregano, which happens to be a Halictus bee magnet.

When I was down 50%, I couldn't help myself. I set up an indoor habitat and brought 1 caterpillar and the last 2 eggs inside to raise. At this stage, the habitat was just a vase made out of a yogurt jar (shown below). Later, I put a large potted parsley plant in my honey-straining bucket and inverted a pop-up hamper on top (not shown).

The larva is easily seen through the shell.  7/11/19

After hatching, the caterpillar eats its shell. Apparently, it's a nutritious meal. I waited a long time then gave up and did not capture it on video.

Video of the caterpillar hatching from its egg.

Be careful when buying plants. The parsley in my garden came from the supermarket produce department, so I assumed it was non-toxic. [insert corny saying about ass-u-me] Not long after passing its first frass (poop) the first-born caterpillar died, and it dawned on me that the parsley wasn't clean. Neonicotinoids are systemic pesticides that wreak havoc on larvae. I'm growing exactly one organic carrot (a whole 'nother blog post) so transferred two day-old caterpillars to a carrot leaf, and off to Nick's Garden Center I went in search of new plants. They sell non-GMO 'Titan' parsley, and I found some bronze fennel. I read somewhere that Black Swallowtail caterpillars love it but mine opted for it last, only eating it when they were close to their final molt and ravenous.

The first instar (newly hatched caterpillar) is black with a tiny band of white, sometimes called the "bird poop mimic" stage. Though described as eating machines, you may not notice them eating much at this tiny stage. This caterpillar is on a carrot leaf. 7/12/19 

Their favorite food was the organic dill (sprigs) that I got from the produce section of the supermarket. In our dry environment, just laying the leaves in a plastic container isn't practical. They stay edible longer in a water-filled jar. A single leaf is plenty for the very young caterpillars. I just poked new holes in a paper towel and inserted more/fresh leaves as needed. The "cats" never wandered off the leaves – at least not until they were much older – but I put the vase in a container overnight to protect them from a very active spider season. Side note: Yoplait's Oui French yogurt is pricey but quite good!

Two first-instar caterpillars on a sprig of dill. Zoom in and you'll see lots of frass, the tiny specks on the paper towel. It's important evidence that your caterpillars are eating. 7/15/19

I found that the tiny ~2mm caterpillars preferred the tender dill but as they grew were more open to eating the tougher parsley and carrot leaves.

Just molted to 2nd instar. The caterpillar now sports orange spikes. 7/15/19

A caterpillar's cuticle (nonliving skin) doesn't grow with the caterpillar. Instead the caterpillar grows inside its skin. When it can't stretch anymore and becomes too small, the caterpillar molts, or sheds the skin. A caterpillar has spinnerets under its head, which it uses to produce silk to attach its prolegs (last set of feet) to the plant stem. The caterpillar does nothing (seemingly) for a full day and then shimmies out of its cuticle. It is actually fasting during the day of nothingness. After molting, typically it will turn around and eat the shed skin, leaving no evidence that could attract predators. In all, it will do this five times. Each stage between molts is called an instar, which looks entirely different from the last. The caterpillar is a bit pale when freshly molted and its color deepens as the skin matures, and within hours you should be able to identify the instar by its new look.

Older 3rd instar (7/17/19)

Younger 3rd instar (7/17/19)

As third instars, they started needing more leaves and as 4th they started getting curious and began to roam. This is when I gave them their first potted plants and put them in the honey bucket. Granted they were small plants, being just purchased from the nursery, but the cats ate the parsley down to nubs and left the bronze fennel untouched. As 5th instars, they lost their pickiness despite having a big, fresh parsley plant.

These caterpillars hatched within an hour of each other but one was always a day or two ahead of the other as they developed, so they consistently looked slightly different. (No, it's not because one's a male and the other's a female. We won't find out their sex until they're butterflies.)

4th instar caterpillars.

Mine are a black variation of Black Swallowtail caterpillars. Every website I referenced shows very green caterpillars at this stage. (I hope to share photos of the butterflies with @arizona_gardener, who raises all kinds of butterflies. He may be able to ID them even if they're a hybrid.)

Molting to 5th instar. 7/22/19

Molting starts with popping off their lenses (head capsule). Then, rather than crawling out of the old skin, the caterpillar shimmies it down, like taking off a pair of really tight pants. One-legged pants. With no hands.

It takes a half-hour or more for the eyes to become fully colored. If you look closely, you can see the dark yellow band which is the osmeterium.

When provoked, a forked gland may pop out of the caterpillar's head. The osmeterium "secretes strong-smelling defensive terpene compounds." Sorry, due to allergies and being perpetually congested, I can't tell you what it smells like. No, caterpillars aren't aggressive toward one another. The caterpillar on the left just had a different reaction to my poking them. Any more questions? LOL

The osmeterium is a defensive organ found in all papilionid larvae.

Pay attention now! If your fifth instar caterpillar stops eating and goes on a walkabout, wandering far from its regular grazing area, it's looking for a safe place to pupate. A sure sign is a "purge" or large, very wet blob of frass. No need to post a photo… you'll know it when you see it. And when you see it, it's go time! Some people drop the caterpillar into a paper bag or gizmo but I let mine wander and pick their own place, within the butterfly habitat that is. In addition to their potted host plants, I offered my caterpillars a paper bag and stalks cut from my day lilies. Both started their walkabouts in the evening, and I found them anchored to their chosen spots the next morning.

The 5th instar has no spikes.

Secured with a strand of silk, a girdle, this pre-pupal caterpillar is preparing for its final molt to become a chrysalis.

Prepupa is the last stage before forming a chrysalis. 7/27/19

After finding the caterpillars girdled in place, nothing happened for a good 24hrs. At least nothing visible was happening. Just as before, the chrysalis skin is underneath what you can see, so it must take that time for it to properly form. I kept checking and checking and finally just went to bed, and the next morning found the head and skin discarded below the chrysalis. Pretty amazing, huh? There's a really great video on YouTube if you don't believe me.

Head capsule and shed skin found on the ground below a chrysalis.

One chose a fennel stalk. The other one chose a day lily stalk, also green so both chrysalides are green. Unlike Monarch butterfly chrysalides which always look the same – super cool – swallowtail caterpillars camouflage their chrysalis somehow, so if it attaches to a brown stick the chrysalis will be brown. Caterpillars planning on going into diapause (in which case the butterfly won't emerge until next Spring) supposedly make brown chrysalides for better camouflage through the Fall and Winter.

About 24hrs later. 7/28/19

Depending on environmental factors, the butterflies will emerge in a week or two/three. To keep the pupa from going into diapause, one should keep the chrysalis somewhere where it will get at least 14 hours of light a day. Stay tuned for Raising Black Swallowtail Butterflies, Part II!

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It's been a long time since I posted a long-format piece so if I was confusing or seemingly left something out, please leave a comment below.