r/MonarchButterfly Mar 06 '25

Overwintering numbers are better this year!

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114 Upvotes

r/MonarchButterfly Sep 13 '24

Let’s talk about OE: what it is and what to know

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111 Upvotes

Hey everyone! Reposting because my text didn’t attach to my first post for some reason.

I’ve been noticing a lot of questions around OE lately, and I thought it might be helpful to provide some information for those who care about the science behind raising monarchs and keeping them healthy. Ophryocystis elektroscirrha—or OE for short—is a protozoan parasite that affects monarch butterflies and other members of the Danaid family. So, let's dive into the key details!

What Is OE?

OE is a naturally occurring, single-celled parasite that’s been found in monarchs for thousands of years. It co-evolved with the monarch and is particularly good at surviving and spreading among them. Unfortunately, human intervention—mainly improper rearing and tropical milkweed use—has contributed to a sharp rise in OE infections, as seen in the graph above. In some areas, more than 10% of monarchs are infected during the summer months alone.

How Does OE Affect Monarchs?

When OE infects a monarch, it can have devastating effects on its development:

Caterpillars ingest OE spores from milkweed leaves, which then multiply within the caterpillar.

Once the butterfly emerges from its chrysalis, millions of OE spores cover its body, especially around the abdomen.

These spores can cause deformities in the wings, preventing the butterfly from being able to fly. In some cases, the butterfly may look normal but still carry the infection.

Infected butterflies also struggle to migrate, live shorter lives, and contribute to the overall weakening of the monarch population.

How Does OE Spread?

OE spores spread like glitter. Monarchs lay eggs on (and eat nectar from) milkweed, and as they land, the spores drop onto the plant. When caterpillars start munching on the leaves, they ingest these spores, which kick-starts the infection cycle again. Since spores are invisible to the naked eye, they can easily spread through contact with infected butterflies and contaminated containers during home rearing.

Controlling the Spread

Preventing the spread of OE requires diligence, especially for those rearing monarchs at home. Some important steps include:

  • Limit overcrowding: One of the easiest ways to promote the spread of OE is by cramming too many caterpillars into small spaces. Keep Numbers to single digits per container is best practice.
  • Maintain strict hygiene: Clean your rearing containers regularly to remove frass (poop) and any potential OE spores.
  • Separate life stages: Keep caterpillars, chrysalises, and butterflies in different containers to prevent cross-contamination.
  • Use fresh milkweed: Make sure you're feeding them clean, pesticide-free milkweed. Tropical milkweed can contribute to the spread of OE, so consider planting native varieties instead.

What to Do with OE-Infected Monarchs

Finding out your monarch is OE positive can be heartbreaking, but it's a reality we all have to face. According to Monarch Science, butterflies that test positive for OE should not be released into the wild. These butterflies will spread the parasite to other monarchs, weakening future generations. Humane euthanasia is often recommended to prevent further spread, but it’s a tough decision. If you're unsure how to handle this, take a deep breath and please look at one of the resources listed—facing the science is part of learning to be a responsible monarch steward, but ultimately these decisions are yours alone to make.

Best Practices for Monarch Rearing

To be the best monarch steward you can be, here are a few science-backed recommendations:

  1. Test your butterflies: Use a simple scotch tape test to collect OE spores from a butterfly’s abdomen and check under a microscope with 40x magnification. It’s the only way to truly know if they are infected.
  2. Plant native milkweed: Avoid tropical milkweed, which can disrupt migration patterns and contribute to OE spread.
  3. Keep things clean: Cleanliness in your rearing setup is critical. Disinfect containers and change milkweed frequently.
  4. Raise fewer monarchs: It's tempting to raise dozens at once, but focusing on quality over quantity will help you avoid overcrowding and keep your butterflies healthier.

Statistics to Keep in Mind - Historically, OE infection rates in the monarch population were less than 1%.
- However, in recent years, those numbers have jumped to 10% or more in some areas. - Southern Florida has OE infection rates near 100%, largely due to the year-round presence of tropical milkweed.

OE is a serious issue for monarchs, but by staying informed and following best practices, we can all do our part to protect these amazing butterflies. If you're rearing monarchs at home, remember to keep it clean, keep it spacious, and keep learning. Every healthy butterfly counts!

I hope this helps answer some of your questions about OE. Feel free to check out these resources if you'd like to dive deeper (I can’t link more than one source so please ask me if you need help finding anything!): - Monarch Parasites: OE Basics - PBS Video: Parasite Affecting Monarch Butterflies - Butterfly Lady: What is OE?

Let’s keep learning and doing the best we can for our fluttery friends! 🦋


r/MonarchButterfly 1h ago

My milkweed is finally coming up :)

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Upvotes

r/MonarchButterfly 6h ago

What’s happened here?

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24 Upvotes

This guy started his chrysalis but never completed it. Anyone know what happened?


r/MonarchButterfly 7h ago

Caterpillars in Mobile,AL

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11 Upvotes

We started our pollinator garden three years ago, added Milkweed last year and replaced it this Spring - yesterday we found three caterpillars on our small Milkweed just in time for a Thunderstorm and unexpected cold snap. We put a shelter over the plant but I’m still worried about getting them through the weather. Any advice is welcome!


r/MonarchButterfly 6h ago

Look at these happy grubs

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6 Upvotes

r/MonarchButterfly 8h ago

Does tropical milkweed deserve a bad rep?

8 Upvotes

I’ve seen a lot of people say tropical milkweed is harmful and should never be planted but the truth is this issue is a lot more complicated. It’s not just about one plant being good or bad. There’s a lot of debate among scientists and researchers and the actual research isn’t as black and white as people make it sound.

Some scientists are concerned about tropical milkweed because it doesn’t die back in winter like native milkweeds. That can lead to a few problems. One is the spread of OE a parasite that affects monarchs and can build up on plants when they’re left growing all year. Another is that monarchs might stop migrating if they have a constant food source which throws off their natural life cycle.

But that’s where cutting it back comes in. Scientists have said that trimming tropical milkweed regularly like once a month during the growing season helps stop OE from spreading and encourages monarchs to keep migrating like they’re supposed to. So it’s not that tropical milkweed is always harmful. It just needs to be managed right.

Also it’s important to remember that any badly managed milkweed even native types can also become a problem. If native milkweed gets overcrowded or left in poor conditions it can still help spread disease just like tropical milkweed. It’s not just a tropical issue it’s a management issue.

Some experts like Hugh Dingle have said banning tropical milkweed doesn’t really address the main issues monarchs are facing which are habitat loss pesticides and climate change. Chip Taylor from Monarch Watch and others have pointed out that tropical milkweed can actually be helpful if people cut it back and grow it responsibly. Monarchs need food and in many areas people have already removed so much habitat that tropical milkweed might be one of the few things left helping them.

That’s why saying things like no milkweed is better than tropical milkweed can be dangerous. If people hear that and stop planting milkweed altogether monarchs could lose even more of the food they rely on. A badly managed plant is a fixable issue. No food at all is not.

Yes tropical milkweed can have higher cardenolide levels under stress like heat but monarchs also feed on native milkweed species with high levels. There’s no solid proof that tropical milkweed is causing widespread harm in the wild. A lot of the studies people reference are still experimental or limited in scope.

Also just because it’s not native doesn’t automatically make it bad. There are examples like eucalyptus that were once thought to be harmful but ended up helping monarchs in some areas. Same could be true for tropical milkweed when used responsibly.

It’s okay to be cautious but treating tropical milkweed like it’s always the enemy misses the bigger picture. Monarchs need our help and we should be focusing on solutions that actually support them not scare people away from planting the very thing they depend on.

Moral of the story is the debate around tropical milkweed isn’t as black and white as some people make it. The truth is we don’t know for certain the true cause of the OE or migrating issues. Anyone telling you in certainty they know is spreading misinformation. They may mean well but is harmful advice.

Sources:

https://news.illinois.edu/report-milkweed-losses-may-not-fully-explain-monarch-butterfly-declines/?

https://ucanr.edu/blog/bug-squad/article/tropical-milkweed-doesnt-deserve-bad-rap

https://texasbutterflyranch.com/2021/02/22/tropical-milkweed-impact-on-monarch-butterflies-vastly-overblownsays-longtime-butterfly-researcher/

https://naba.org/wp-content/uploads/2024/04/Tropical-Milkweed.pdf

https://agrawal.eeb.cornell.edu/2020/03/02/qa-about-tropical-milkweed-asclepias-curassavica/


r/MonarchButterfly 23h ago

Going to be a busy year!

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90 Upvotes

I ran out of my planted native, so resorted to “feeder” tropical plants. This was after 3 hours with the plant, and there were 4 others in the habitat! (I have plenty more in reserve)


r/MonarchButterfly 7m ago

Are these milkweed sprouts? I live in northwest IL

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r/MonarchButterfly 20h ago

Chrysalis sighting

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26 Upvotes

r/MonarchButterfly 14h ago

📍New Zealand

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5 Upvotes

Finally managed to get one eclosing on Timelapse! I had three eclose yesterday, two perfect boys and one beautiful girl :)


r/MonarchButterfly 16h ago

Thoughts on my plant?

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5 Upvotes

I can post better pictures but right now this is the only milk weed plant I have. Started off with 3 plants and they got savagely eaten up so now I combine them all into one pot. But I feel like it can still grow some more and get bigger and get more leaves. Any fertilizer recommendations or suggestions things I should put in the pot to make it grow?


r/MonarchButterfly 1d ago

A butterfly love story 🦋🦋

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105 Upvotes

This little guy and lady:

  • Were always on the same branch, never more than a couple inches from each other
  • Chose chrysalis spots right beside each other
  • J hang and pupated at the exact same time
  • Both had their silk pads detach from the mesh at the same time, and I witnessed both chrysalises fall together.
  • I pegged them both up close to each other (but with plenty of room) as they were close to eclosing
  • Emerged within minutes of each other, and flew off together.

I’ve truly never seen this happen with monarchs, has anyone? These two were inseparable fatties (last pic), transformed together, and blissfully departed into their new life together. 🦋🦋


r/MonarchButterfly 1d ago

Drunk on Giant milkweed

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65 Upvotes

r/MonarchButterfly 1d ago

The very curious case of the disappearing milkweed

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24 Upvotes

A lot of hungry mouths to feed !!!!


r/MonarchButterfly 2d ago

Tropical Milkweed is an issue whether you like it or not.

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62 Upvotes

You can’t (or you can if you really don’t care about the Monarchs you are killing trying to support) ignore the science. Tropical milkweed is a major contributor to OE, its evergreen and in warmer climates can be toxic to the caterpillars who consume it. When you go to your local nursery make sure to ask if the milkweed you are buying is native. Do a little research on how to stop Tropical milkweed. This goes for giant milkweed as well.


r/MonarchButterfly 2d ago

Spotted in Houston last weekend.

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245 Upvotes

r/MonarchButterfly 4d ago

Caterpillar chose right above my door for their chrysalis

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213 Upvotes

I saw them climbing the wall yesterday and noticed they were staying above the door and I was like that’s definitely gonna be their spot. They made a J formation a couple hours later and then this morning they are fully formed into their chrysalis :)


r/MonarchButterfly 4d ago

Sun Washed Monarchs.

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31 Upvotes

r/MonarchButterfly 4d ago

This butterfly has a radio tag with a tiny solar panel for tracking migration

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434 Upvotes

r/MonarchButterfly 4d ago

Milkweed Dream

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9 Upvotes

My latest attempt at growing milkweed. This was a larger seedling I transplanted last fall. I cut the bottom from a Folgers coffee container to protect it. Zone 7b. 🤞🏻


r/MonarchButterfly 4d ago

Museum collections reveal worldwide spread of butterfly disease

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10 Upvotes

r/MonarchButterfly 5d ago

Question about "butterfly houses."

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33 Upvotes

I'm working on getting my pollinator garden (zone 8a): got my milkweed going and various other nectar plants growing.

Now I'm working on tidying up the patio in the garden and thinking about some "pollinator accoutrements" like a watering station, bee hotel, hummingbird feeders, etc.

I love the idea of a butterfly house like the one pictured, to give butterflies (especially our traveling monarchs) a safe place to rest overnight. But... will butterflies actually use something like this? And my bigger question is if they do, can they get back out?? Like, I know that they just need to fold their pretty little wings and crawl out one of those slots, but do THEY know that? Lol

And if not, any suggestions on creating an appropriate overnight resting spot for butterflies in my garden?

TIA!


r/MonarchButterfly 4d ago

Egg ID

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5 Upvotes

Hey everyone! Planted my first milkweed this year and I was just wondering if yall thought this was an egg? I am dying to get some monarchs in the garden and saw one the other day, but I couldn’t tell if this was an egg or not. Thanks!


r/MonarchButterfly 5d ago

A pretty little lady emerged this morning!

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176 Upvotes

And mistook me for a bush 🌳 Her plantmate was the male that hatched a few days ago! Included photo of them sharing a plant. Hope they find each other again!


r/MonarchButterfly 5d ago

Is this a bad egg?

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11 Upvotes

Usually there’s only black at the tip of the egg, right? Thanks! I’m in SoCal if that’s important. (Don’t mind my nails)


r/MonarchButterfly 6d ago

How many can you count?

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52 Upvotes

Different angles of the two plants with the most cats.