Rearing Monarchs
Only about 1-3% of Monarchs in the wild survive to adulthood. There are so many predators! If you really want to help them and bring their odds of survival up to 95% or better, consider bringing them inside to foster! Rearing Monarchs is easy, educational, and fun!
The Life Cycle of the Monarch
Before you begin to raise Monarchs, you must first understand their life cycle. Most Monarch Butterflies east of the Rocky Mountains, spend the winter in sanctuaries located in the Mariposa Biosphere Reserves in the Oyamel Fir Forests of central Mexico. There are 12 sites, representing about 62 square miles. In February and March, the Monarchs come out of their winter diapause (hibernation) and head to the north and east into the United States and Canada. These Monarchs will mate, with the female laying the eggs of the first generation of the year. There are four generations of Monarchs each calendar year.
The female Monarch lays her eggs exclusively on milkweed. Milkweed is the only plant that Monarch larvae will eat. Eggs are generally laid on the underside of the milkweed leaf.
The female Monarch lays her eggs exclusively on milkweed. Milkweed is the only plant that Monarch larvae will eat. Eggs are generally laid on the underside of the milkweed leaf.
The egg will hatch in about 3-5 days. The larva will eat the remains of the egg before eating milkweed.
(Thank you to my friend, Sara Yousa, who used her extraordinary photography skills to get these photos of the newly hatch larva eating its eggshell!)
As the larva grows, it will go through five "instars" starting with the egg, then eating the remains of its skin as it grows. As it transitions, the larva will appear motionless for a period of time. It will then shed its skin and eat it before returning to eat milkweed. It is best to try not to disturb the larva as it goes through its instar phase.
The larval stage lasts about two weeks. The larva will munch greater and greater quantities of milkweed until fully grown. It will also produce greater an enormous amount of frass (poop)! It seems that in no time at all, the larva goes from being practically microscopic to huge!
Here is a little Monarch caterpillar anatomy for you. The mandibles are responsible for shaving the milkweed that the larva eats. The spinnerettes produce a fine silk that keep the larva from getting lost and for spinning a button from which the larva will hang as it begins its metamorphosis. The spiracles are how the larva breathes, so be mindful of this if you are holding one.
When it is fully grown, the larva will leave the milkweed. In the wild, the larva can travel quite far to find a quiet place to begin its transformation. Inside, the larva will likely go to the top of your container or a branch placed inside your container to begin metamorphosis. The larva will use its spinnerettes to spin a button of silk. The larva will then dig its anal prolegs into that button. It will drop its head into a "J" position where it will hang for up to 24 hours, seemingly doing sit-ups from time to time. Suddenly, its skin will split to reveal the green chrysalis. A barbed-like spike, called the "cremaster", will dig itself into the silk button to further affix the chrsalis in position. Initially, the chrysalis appears to be dancing as it slowly hardens.
The "Pupa Dance"
Though all seems quite on the outside, inside the chrysalis a rapid metamorphosis is occurring. The parts of the larva are changing into the beautiful parts of the butterfly. This process takes about 9 days. The chrysalis will change from bright green to opaque to so clear you can plainly see the colors of the Monarch butterfly inside. When you see those colors, your butterfly is about to emerge.
It is extremely important that the Monarch be able to hang onto something after it emerges. Most often, they hang directly onto their chrysalis. Occasionally, they will fall. Sticks placed inside your container can be helpful. The sticks allow an opportunity for the Monarch to climb onto something. Monarchs need to hang upside down in order to pump out and dry their wings. If not, they could become crippled and unable to fly.
As the Monarch comes out of its chrysalis, you will notice that its wings are small and that it has a huge abdomen. Their abdomens are full of the fluid needed to pump out those wings. This process takes only about 15 minutes. Then, those wings need about 4-6 hours to fully dry. In the above, right hand picture, the Monarch to the far right has that huge abdomen and those small, soft, wrinkly wings. Notice all the Monarchs in that container are hanging onto their chrysalises. Also notice that you can clearly see the Monarchs in chrysalis getting ready to emerge. Most Monarchs emerge during the morning hours and can be released, weather permitting, that afternoon.
As the Monarch comes out of its chrysalis, you will notice that its wings are small and that it has a huge abdomen. Their abdomens are full of the fluid needed to pump out those wings. This process takes only about 15 minutes. Then, those wings need about 4-6 hours to fully dry. In the above, right hand picture, the Monarch to the far right has that huge abdomen and those small, soft, wrinkly wings. Notice all the Monarchs in that container are hanging onto their chrysalises. Also notice that you can clearly see the Monarchs in chrysalis getting ready to emerge. Most Monarchs emerge during the morning hours and can be released, weather permitting, that afternoon.
On a sad note...
You may sometimes find (hopefully rarely) that you have a sick larva that does not recover. As mentioned earlier, sometimes adult Monarchs may fall, damage their wings, and be unable to fly. The best thing you can do is to euthanize them. And the kindest way to do that is to place the Monarch larva or butterfly in a plastic bag and put them in your freezer. Easier said than done, right?
Monarch Enemies
Monarchs have many predators. Again, only a very small percentage survive in the wild. You can be an enormous help if you foster them inside your home!
Ants Tachinid Fly Leaf-rolling Spider
Ants, leaf-rolling and other spiders, wasps, and Asian Lady Beetles will all eat Monarch eggs and larvae for protein. Tachinid flies are especially dangerous to Monarchs. The fly injects the Monarch larvae with its own eggs. The Monarch larvae will continue to go through its life stages and into chrysalis. Then, the Tachinid fly larva takes over and your butterfly is dead. Birds, like robins, orioles sparrows and cardinals will also eat the larvae and butterflies, those most birds find Monarchs distasteful. By the time the birds figure that out, it is too late for the Monarch. Sudden weather changes can also greatly affect Monarch larva and butterflies.
Supplies for Rearing Monarchs
Rearing Monarchs is easy! All you need are a few, simple supplies, an little bit of time each day, and PLENTY of milkweed!
Each day, the larvae are removed from your container and placed on a fresh milkweed leaf. Any larvae over one-half inch in size can be handled. Smaller larvae should be gently brushed from the old milkweed onto fresh milkweed. Dispose any milkweed stems and old milkweed leaves. Paper towels with frass can easily be picked up and thrown away. The container can then be sprayed with a dilute bleach solution and should be allowed to stand for about 10 seconds. Then, thoroughly rinse and dry the container.
The container is lined with a new paper towel (to catch the frass). The larvae can then be put back into the container with fresh milkweed leaves. One very important note: you can store milkweed leaves for a few days in a sealed Ziploc bag in the crisper section of your refrigerator, much the way you store lettuce. You are going to need A LOT of milkweed! Monarch larva can "skeletonize" a milkweed leaf in no time at all!
If you happen to see a Monarch larva that is acting different, is discolored, has diarrhea and/or vomiting, please separate that larva from the rest of your group, but continue to feed it. There may be no reason for the quarantine, but it is better to be safe than sorry.
The container is lined with a new paper towel (to catch the frass). The larvae can then be put back into the container with fresh milkweed leaves. One very important note: you can store milkweed leaves for a few days in a sealed Ziploc bag in the crisper section of your refrigerator, much the way you store lettuce. You are going to need A LOT of milkweed! Monarch larva can "skeletonize" a milkweed leaf in no time at all!
If you happen to see a Monarch larva that is acting different, is discolored, has diarrhea and/or vomiting, please separate that larva from the rest of your group, but continue to feed it. There may be no reason for the quarantine, but it is better to be safe than sorry.
If you have any questions about rearing Monarchs or need help trouble shooting, please feel free to contact me via this site. I will get back to you quickly.
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