posted by Allyson Scott

The natural world is full of miraculous stories, but is there anything more astonishing than the life cycle of the monarch butterfly? These seemingly delicate little creatures are hardier than most people imagine, and I’ve documented my efforts to help their population in some small way over the last few years.

The monarch story takes place in four stages over four generations.

Monarchs overwinter in the warmer climate of Mexico (and some areas of the southern United States), where habitat destruction has contributed to the decline in their numbers the last few years. Two beloved butterfly activists at one Mexican sanctuary recently lost their lives trying to protect the species from illegal loggers.

The butterflies come out of hibernation in February and March, when they try to find a mate and begin their migration northeast. In March and April, the travel-weary butterflies will lay their eggs on milkweed plants (nothing but milkweed) to start the first generation of the new year.

I noticed I rarely saw even medium-sized caterpillars on my plants, and never once found a chrysalis. It was my hope of improving the survival rate that prompted me to do some research on this very helpful website, where I could purchase a couple of mesh butterfly cages and begin running interference.

The threats to each life cycle stage are varied and constant. The milkweed plants, the monarch eggs, and the caterpillars are all susceptible to poisoning from weed killer or insecticides, and of course people just removing the weedy plants. The caterpillars and butterflies can also become a food source for predators such as birds, wasps, and spiders, and there are many diseases that can affect the growing caterpillar and/or chrysalis.

The best advice for success is to harvest the eggs as soon as they are laid, before any parasites have had time to infect the egg or caterpillars. The tiny eggs are just visible to the naked eye, and appear milky until the caterpillar inside is nearly ready to emerge. The little dark speck of its head becomes visible and hatches in about 4 days (photos taken with an iPhone and olloclip macro lens).

Once the tiny baby caterpillar emerges, its own eggshell becomes its first source of food before it begins munching on the milkweed leaf.

Now in its second stage of life as a larva, the caterpillar will need to eat an enormous amount of milkweed to support the incredible amount of growth it must achieve. When the caterpillar becomes too large for its skin it molts, often eating the shed skin left behind.  It will go through 5 “instar” molts over 10-14 days, growing fat and developing deeper colours.

When caterpillars are about to molt, they will often wander a good distance away from the leaves, and may sit there for 24 hours or more. Don’t try to touch or move them, as you could cause them serious harm.

Also, guess where caterpillars love to perch while molting? On the zipper of the mesh cage. Always, always, always take a close look at the inside of the zipper before opening it. It does not end well for your beautiful caterpillars if you don’t. 🙁

The daily care of the caterpillar compound includes providing fresh, well-washed milkweed leaves (that often sport new eggs, which you might want to safely place in a different container), and clearing out the enormous amount of leaf detritus and poop the caterpillars produce. You should also spritz the leaves, caterpillars, and chrysalides with clean water once a day to keep them all hydrated.

Some research has shown that if you raise caterpillars/chrysalides entirely indoors, they may not develop a sense of direction and won’t be able to successfully migrate later as butterflies. I keep my cages on my outdoor patio where they can experience sun, wind, and some light rain, but I bring them indoors if the weather turns truly stormy.

Once the caterpillars are as fat as they are going to get, they will crawl to either the underside of a large leaf or to the top of the cage, and intricately weave a strong silk mat with a silk “button”. They turn around and attach their hind ends to the button, and hang in a “J” formation.

Over the course of 24 hours, the hanging caterpillar will do little ab crunches, slowly turn a greenish hue, and eventually its body and antennae will hang fully limp. The caterpillar’s skin will split at the bottom (which is actually the top of its head), and it will rhythmically pulse and spin around to shed the skin and emerge as a soft chrysalis. Over the course of a few hours it will harden and develop the signature metallic gold specks, which are actually ports of entry for oxygen!

Want to watch a caterpillar form a chrysalis in my cage? Check this out!

When it’s successful, it’s magnificent. When it’s not, it can be more upsetting than you’d imagine.

Now in its third life stage as a pupa, we are finally able to figure out the sex of the future butterfly!

The little black “stem” the chrysalis hangs from is called the cremaster. Below the cremaster are little black dots, and below those are the rings of the abdominal segments. A female butterfly will have a clear indented line where its sex organs are. A male will not.

It takes another 10-14 days for the caterpillar to fully form the butterfly’s organs and body parts. When the butterfly eventually breaks open the shell of the chrysalis to “eclose”, or emerge, it will be wet and must have room to hang and dry its wings fully extended. Sometimes the caterpillar didn’t take this into account, and created the chrysalis in inconvenient or improbable places.

This one formed “in the wild” right above a gate latch that receives a lot of traffic. The solution is to tie some tooth floss around the cremaster, carefully remove the silk pad, and use a safety pin or hot glue to hang it inside the cage.

After a chrysalis matures, it turns completely transparent and you can see the monarch butterfly all folded up inside. It will eclose within 24 hours, usually in the morning so that the butterfly has time to dry in the sun. If there is stormy weather, the butterfly will often manage to delay this last stage for more favourable conditions!

It took a lot of time and a little luck to film this process. Watch a butterfly eclose!

Of course, when you are raising butterflies and want to go away for the weekend, you either need to get an experienced babysitter to scoop the poop and wash fresh leaves…or you have to take the kids with you on vacation!

As I was packing the car for a visit to a friend’s cottage, one butterfly decided this was the time to come out and play, so she would ultimately need to be released when I reached Haliburton. Imagine my surprise when I arrived, opened the egg carton that I use to hold the stems of milkweed, and discovered several caterpillars had crawled inside and formed chrysalides! They would all need to be rehung inside the cage.

It was exciting to share this process with my friends, one of whom just happens to be a veterinarian! As the resident animal expert, and as the new cottage owner hosting our girls weekend getaway, Jenn was the lucky one to launch the butterfly on her travels. I silently apologized to the monarch for adding three hours to her migration.

The first, second, and third generations of monarch butterflies only live between 2-6 weeks, with their entire purpose being to mate and reproduce. The fourth generation of monarchs born in September and October are the anomalies: they live for 6-8 months, migrate up to 4,000 km to overwinter in Mexico, and then begin the journey north to create the next year’s first generation.

2020 was a disastrous year for many people who enjoy raising monarchs, and I had not a single successful butterfly release. 2021 is a completely different story! I’ve released around 30 butterflies since June, and have 12 more chrysalides that I am hoping will make it for the fall migration!

Safe travels, you beautiful creatures!