How to Hunt, Gather, and Protect Monarch Eggs-Raise The Migration 2020
by Anthony Gomez
A month ago
First we’ll hunt, then we’ll gather, and finally we’ll find a safe place for your monarch eggs to rest and develop until hatching…
Hunt For Eggs
Where should you look for monarch eggs? Here’s a list of places where many monarch raisers are finding their migration eggs:
- Small milkweed seedlings that have popped up over the summer
- Rabbit-ravaged plants (with fresh growth)
- Lone milkweed plants located away from large patches that are chocked full of predators…potted or garden plants
- Late season fresh-leaved milkweed varieties including tropical milkweed, balloon plant, swamp milkweed
- First year perennial milkweed seedlings w/ fresh leaves including common, swamp, butterfly weed
- Milkweed in partial shade typically has fewer predators and the plant leaves stay fresh longer with breaks from the sultry summer ☀️
- Buds of milkweed including tropical and giant
- Seed pods
- Nearby non-milkweed plant leaves or blades of grass…accidents happen! 🙃
- You can also find caterpillars on the lowest sets of leaves. When you all-of-the-sudden see a large 🐛 on your previously ‘unoccupied’ milkweed, that’s probably where it was hiding out.
Of course, monarch females are the queens of egg-hiding, so leave no milkweed leaf unturned!
A big thanks to community member Robert W. for reminding me that monarchs aren’t the only mamas that lay eggs on milkweed. Here are some close-up monarch egg photos for those who aren’t quite sure what they’re looking for. Notice that monarch eggs have distinct ridges:
If you have a hard time seeing small monarch eggs, try using a magnifying glass to confirm your findings.
Gather Your Eggs
This is how we started collecting eggs (almost exclusively) in 2017 because it works no matter how you plan to raise your caterpillars after they hatch…
- Use a bowl or bucket to place any eggs you collect. Make sure this container is deep enough so leaves/eggs won’t blow away.
- If you find an egg on a leaf, gently pull down where the leaf petiole attaches to the milkweed stalk to remove the entire leaf.
- If the egg is on the stalk or flower bud, use your pruning snips to cut off a small piece of the plant
Once the eggs are inside, you have a couple options…
- Put a dry paper towel in the bottom of a food container (wet paper towels can cause monarch-killing mold.)
- Use snips or a scissors to cut off a leaf piece that contains the egg. If you have enough space in the container, you can keep the leaves whole.
- Check leaves for potential predators or foreign eggs.
- Take each leaf or leaf piece, and gently rinse it under a faucet without blasting the egg.
- Place each leaf egg-side up on the paper towel.
- Space out the eggs across the paper towel so that no baby caterpillar will accidentally eat its unhatched neighbor. In the 6” x 6” x 2” containers below, we put about 6-10 eggs per container. We’ve recently upsized to containers that measure 9” x 9” x 3” (9 cup) and 16” x 11” x 3.5h” (1.5 gallon) which can hold up to 20 monarch eggs and wee cats. 🐛
- Seal the food container lid.
note: while some poke small air holes in the lid, this is not necessary. There will be more than enough oxygen in the container from your daily checks. 🔍 No holes will also prevent any potential baby caterpillar escapes.
Use whole milkweed leaf cuttings of swamp/common/tropical/giant in florist tubes. Rinse each leaf thoroughly with water, but be careful not to wash away the egg. They are usually stuck like glue to the leaf.
Keep in mind, leaf petioles are short so you will need to make some leaf adjustments to eliminate the need for daily floral tube refilling…
Tip: Cut leaf away from both sides of the midrib to submerge the leaf further inside the tube for less refilling. In the photo above, I was able to submerge the leaf stem half way down the floral tube by cutting away the leaf.
When cutting around the midrib, it’s easiest to do this from the back where the midrib sticks out. This egg was located toward the bottom of the leaf so I wasn’t able to submerge the stem as deep:
Submerging the midrib 1/3 to 1/2 way down the tube will suffice as one leaf will not absorb much water compared to a stem cutting. This method eliminates having to transfer baby caterpillars to new milkweed after hatching:
Why Not Bring in Eggs on Stem Cuttings or Plants?
- Hard to Keep Track of Small Caterpillars
- If any eggs have been parasitized by wasps, you might not notice them after they turn dark
- It’s hard to clean cuttings/plants properly while avoiding monarch eggs
If you find the perfect cutting and want to skip the single-leaf step, that’s definitely an option too:
However, hatching them in food containers or on single leaf cuttings will make it easier to keep track of your newborn caterpillars 🐛 🐛 🐛 🔍
Protect Your Eggs
You can keep these mini-greenhouse hatcheries (food containers) almost anywhere, but don’t place them in direct sun. 🌞 🍳 😱
If your eggs are indoors in a mesh cage, I would suggest temps of at least 73°F during the day.
I keep our mesh cages in a 3-season porch, where the windows are left open most of the season so it doesn’t get too stuffy. This exposes the developing monarchs to natural levels of heat and humidity, without exposing them to extreme conditions like wind and soaking rains.
The monarchs need environmental cues so they know it’s time to migrate. If your only option is raising indoors, raise by a window for natural lighting and open it whenever possible.
Our porched eggs and caterpillars get adequate light, but they’re not in all-day sun and I always make sure the clear viewing window on our mesh cages is turned away from direct 🌞 so it can’t magnify heat…we actually had a chrysalis that started melting from this!
During the 🐶 days of summer, we bring the cages indoors if temps go over 95°F. If the overnight low is below 50° F we will do the same…how come?
Cold temperatures slow down metamorphosis. This can be a serious issue around the fall migration because butterflies need to leave before it gets too cold to take flight.
Don’t put your eggs in a cage where there are already butterflies or chrysalises about to hatch. Adult butterflies can spread disease spores on to the milkweed below, and your baby caterpillars will ingest them. This can potentially disfigure them and produce sickly butterflies.
Water for Eggs?
Mesh Cages– Mist the milkweed leaves daily (water from a spray bottle) while you wait for your eggs to hatch. Just a couple quick sprays of water each morning will keep the eggs hydrated and can also wash away potential disease spores.
Sealed Food Containers– these hold in more moisture so mist only if it looks like the leaves are starting to dry out. On average, I spray the leaves inside the food container once before the caterpillars hatch.
Now we wait for your cream-colored eggs to darken, signaling the impending birth of your baby monarch caterpillars…
For further assistance with monarch eggs and raising healthy butterflies through the monarch life cycle, a ✬✬✬✬✬ rated PDF download on How To Raise More Monarchs, with Less Effort is available for purchase HERE