How to Find Monarch Eggs and Caterpillars

6/16/2020

Finding monarch eggs and caterpillars is an exciting experience, especially if it's your first time! It can be a bit more difficult to find immature life stages of monarchs compared to the showy adult monarch. However, when you know what signs to look for, it can be much easier!

If you are wondering when to look for monarch eggs, check the Journey North Monarch Egg Map to find out when they will be in your area!

On the Trail of Monarch Eggs

The best place to look for monarch eggs is on milkweed because it is the only plant that adult monarchs lay their eggs on. The trick is to look on the underside of the leaf but you may sometimes find eggs on the stems or flower buds as well.

**It is important to be very careful when handling milkweed leaves so you don't accidentally crush or disturb monarch eggs. Caterpillars can drop off of plants if disturbed. Pinch the very tip of a leaf and carefully turn it over without shaking the plant.**

A female Monarch butterfly deposits an egg onto the underside of a swamp milkweed leaf. A female monarch can lay 300-500 eggs over the span of two-five weeks. Photo by Sid Mosdell. https://www.flickr.com/photos/sidm/4813477518/in/photostream/

Identifying Monarch Eggs

Monarch eggs could almost pass through the eye of a needle. In other words, very tiny! You may want to use a visual aid such as a jeweler's loupe or camera lens in order to identify the monarch egg. The egg is unique looking in that it is ovular, ribbed and somewhat transparent.

Monarch butterfly egg on a milkweed leaf just before hatching. Photo by Laurie Shaull. https://www.flickr.com/photos/number7cloud/29844659267/

Jeweler's loupes are a wonderful way to get a closer look at monarch eggs and caterpillars. Photo by Rebecca Chandler.

A monarch is in the egg stage for 3-8 days. In order to hatch, it has to eat the eggshell and then begins feeding on the leaf. A single caterpillar can defoliate an entire milkweed plant and sometimes more depending on the plant's size.

Signs of Monarch Caterpillars on Your Milkweed

There are several tell-tale signs that a monarch caterpillar has been on your milkweed. One thing to look for is milkweed leaves that have been chewed on, also known as signs of herbivory.

A milkweed leaf that has been chewed on. Photo by Rebecca Chandler.

Another sign is small dark bits of frass, another word for insect droppings.

Monarch frass on a swamp milkweed plant. Photo by Rebecca Chandler.

Monarch caterpillars go through five instars, or stages between molts. First instar caterpillars are very small and can appear almost translucent or pale green. Subsequent instars are distinctly striped in yellow, white, and black, with a pair of black tentacles on both ends of their bodies. The photo below shows a caterpillar that is next to a molted skin. Monarch caterpillars will grow to about 2,000 times their original size!

If you have followed all the signs, then you will find monarchs! Good luck!

11 Comments

Stephanie Aaron

8/5/2020 05:41:48 pm

Can you tell me - is it possible that Monarch butterfly's may lay unfertilized eggs - and is an egg that turns black a dead egg?
Thank you

Sean

8/20/2020 02:14:09 pm

I had wondered this too. I was watching a monarch and it appeared it lay an egg on a bit of holly near the milkweed. Checking it over some days later there were 3 black dots that seemed to resemble a monarch egg, but totally round, firm and slightly smaller. I’ve found these on several underside milkweed leaves too. I couldn’t determine if they were eggs of another insect, odd frass, unfertilized eggs? But they were firm. Google hasn’t been a help.

John D.

8/23/2020 03:34:01 am

We have been looking for eggs over the past few weeks. While we had much success in finding eggs and caterpillars we have yet to find a chrysalis. How far away from the milkweed have they been known to travel in order to make a chrysalis? I also wonder, is there a specific plant they look for to pupate? So far we have counted thousands of eggs and hundreds of caterpillars but no pupas.

Arlene Cole

9/24/2020 01:51:52 pm

Last year a caterpillar crawled through the garden, up the porch steps, half-way across the porch, and chose an old chandelier that was on the floor, to hang from. I was able to check the progress every day of the chrysalis, which was a breath-taking green and gold jewel like I have never seen. This was the first time I have ever experienced Monarchs up close, and I will spend the rest of my life providing for them. I wish I was able to submit a photo so you can see what I just tried my best to describe.

Michael

8/26/2020 03:21:19 pm

We have an orange flowering plant that comes back each year and we have monarch caterpillars every year. This year we had 12 on the plants at one time. Today we have 2 chrysalis on our porch, about 10-15 ft from the plants. Not sure where the others went.

Kat

8/29/2020 12:52:19 am

The orange-flowering plant is probably butterfly weed, as monarchs only host on milkweed plants.

Mary

9/1/2020 07:42:44 pm

I have lots and lots of milkweed but have never seen a caterpillar or chrysalis. I do see butterflies in the garden. What's going on?

richard harrington

9/2/2020 02:58:44 pm

will small caterpillars survive if I put them in a large jar with fresh milkweed daily ????????????

Jennifer

9/2/2020 09:18:59 pm

Yes! I wrap the tiny stem of the milkweed leaves in a piece of slightly moist (not dripping) paper towel and keep the cats in lidded containers. Clean the poop out twice a day and replace the leaves when needed.

Don

9/6/2020 12:28:32 pm

I've had some some Monarch's laying eggs this week and I noticed that my milkweed plant has a large amount of aphids on it. Will they harm the eggs or larvae?

Reggie

9/27/2020 11:24:50 am

I have milkweed with some penta plants nearby. The Monarch laid a lot of eggs. When the caterpillars hatched from their eggs, they devoured all the leaves on the Milkweed. I counted six chrysalis so far. Many of them have traveled to different areas. I found on on my wife’s car tire.