Life Cycle of a Monarch Butterfly
- Misty
- Aug 18, 2019
- 5 min read
Updated: Jan 30
Most of us, likely learned about the life cycle of a butterfly in school. However, if you're like me, grade school was quite some time ago. So let's have a quick refresher course. We will try to get a little more detailed too.
There are 4 stages: Egg, Larva, Pupa and Adult.
okay that's it... just kidding.
With our last post we learned about host plants. Armed with that knowledge, we know that Monarch eggs are found on it's host plant, milkweed.
First come the eggs. Eggs can be found anywhere on the plant, but are mainly found on the underside of the leaves. The eggs are somewhat oval shaped and slightly pointed at the very top. They have a ridged design on all sides, and have a translucent shine, that really is beautiful in full sun. Monarch eggs take about four days to hatch, but can take up to 10 days (if you raise them indoors, the cooler temperatures will slow this process, and on the flip side, warmer temperatures will speed the process). Monarch eggs are white or slightly yellow, until they get close to hatching. When the baby is nearly ready to emerge. there will be a dark spot on the top of the egg. You are actually seeing thru the egg and the dark part will be the tiny caterpillar's head. (if you have a way to magnify the egg, you can actually see the baby, inside the egg, moving around! It's pretty cool)
The next stage is Larva. Once the caterpillar eats its way out of its egg, it often times will eat the shell, as it's first meal. When the baby hatches, it is about 1/8 th of an inch long (they are VERY tiny), but they don't have that very hungry caterpillar book for nothing! They keep eating thru the whole larval stage, and they eat A LOT! By the end of this stage, they grow to an average length of 2 inches! I'm getting ahead of myself. Some pretty amazing stuff takes place in this stage. The caterpillars have different stages during the larval period, a way to identify which phase they are in, is to figure out which "instar" they are. (See pictures below)
The whole larval stage only lasts 9-14 days, during that time the caterpillar grows so much, that it must shed it's skin five different times (this process is called molting) after each molt, the caterpillar grows and is then in a different instar. (Instar is the name given to arthropod between molts) The caterpillar normally wanders away from its food source, spins a silk pad (so it can hang on while it walks out of its old skin) each time it molts, this takes nearly a day to complete. After it has finished molting, the caterpillars face cap also comes off and it will then eat its skin before it goes back to the main food source. Most times a freshly molted caterpillar will be lighter colored. Sometimes a good indicator of when a caterpillar will be molting soon, is that their face cap will look too small for the size of the caterpillar.
When the caterpillar has finally (eaten all of your milkweed-not really but it seems like it) ...when the caterpillar is ready to pupate, it weaves another silk pad. This last one is much thicker. Once finished, the caterpillar will then attach itself to the silk pad and hang upside down, in resemblance to the letter J. This too, will take about a day, before it's ready to pupate.
The pictures below are an illustration, in relation to a U.S. dime, during the 5 instars of the Monarch caterpillar. Plus 1 additional photo because it's cute.
First Instar Second Instar Third Instar
Fourth Instar Fifth Instar Just because it's cute
Pupa is the third stage. Upon entering this stage, your caterpillar, who was hanging as a "J" will once more, shed its skin. It only takes about a minute to slip out of their striped skin, and then you can only see the newly formed, bright green chrysalis. If all goes as planned, the skin will be on the floor in a little pile (much like your children's clothes in their rooms). After a few hours the chrysalis will take its final shape and begin to harden (it will be fully dried in about 24-48 hours) It will have a slightly waxy type feel, the color will change slightly to a beautiful jade green, adorned with small spots of metallic gold. If you look closely you can see all the parts that will become the butterfly. This stage can last from 10-18 days (just like the egg stage - dependent on temperature)
In my opinion, this is the most fascinating stage. Everything is transforming inside of this little chrysalis! Just like when a baby is forming and developing, all of the necessary parts are being created, so this future butterfly can fly away in just days!
A day or 2 before the butterfly will emerge (eclose), the chrysalis will begin to turn clear. You will start to see the pattern of the wings as well as the orange and black colors.
Shortly before the butterfly ecloses, the chrysalis will be completely clear.
On the day the butterfly ecloses, if you're lucky enough to witness this, try not to blink! it happens so fast! The outer shell of the chrysalis opens, the butterfly then drops down and hangs upside down to start pumping blood into their wings so they can expand and dry. They must also "zip up" their probiscus -which comes out in 2 sections and must be aligned together so the butterfly will be able to eat. All the while precariously hanging from their chrysalis and trying to figure out their new, much longer legs! Shortly after the butterfly ecloses (comes out of the chrysalis) it will release drops of merconium -a reddish fluid that is metabolic waste they have stored, don't worry, nothing is wrong with your new butterfly! About 4 hours or so later, the butterflys wings will be dry enough for him or her to take their first flight! You can then release them and watch them fly on their way!
Make sure you have plenty of flowers waiting for them, so they can come back and flutter around your yard, getting all the nectar they'll need for their travels!
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