r/MonarchButterfly Jun 28 '26

What the Science Actually Says About Rearing Monarch Butterflies

170 Upvotes

We are now getting many posts in this subreddit that try to demonize the rearing of monarch butterflies. If you raise monarch butterflies, you have almost certainly been told that “the science doesn’t support it.” You may have read in this sub that reared monarchs can’t migrate, that rearing spreads disease, or that you are actually hurting the species you love. These claims are often presented as settled scientific consensus.

They are not.

A careful look at the peer-reviewed literature tells a much more nuanced and, frankly, more encouraging story. While there are legitimate questions about large-scale commercial breeding and the importance of rearing under natural conditions, the weight of the evidence shows that small-scale, responsible rearing by hobbyists and educators is not a meaningful threat to monarch populations. In fact, several lines of research suggest it can be a net positive.

Below is a summary of what the published science actually shows.

1. Reared Monarchs Can and Do Migrate Successfully

One of the most persistent myths is that captive-reared monarchs cannot orient or migrate. This claim traces largely to a 2019 laboratory study that tested commercially bred monarchs in a confined flight simulator and found they did not orient south. However, subsequent research has significantly complicated and, in many cases, contradicted that conclusion.

A landmark 2021 study by Wilcox and colleagues at the University of Guelph reared monarchs indoors under controlled conditions and then both tested them in a flight simulator and radio-tracked them in the wild using over 100 automated telemetry towers. While the simulator results showed weak orientation, 97% of the radio-tracked monarchs flew in the correct south to southeast direction once released into the natural environment. The monarchs were detected at distances of up to 200 km from the release site. The researchers concluded that any disorientation caused by captive rearing is temporary and that proper orientation is re-established after exposure to natural skylight cues (Wilcox et al., 2021, Conservation Physiology).

This finding aligns with a large-scale tagging study by James and colleagues, who captive-reared and tagged over 14,000 monarchs across the Pacific Northwest. Of the 182 that were later recovered, the vast majority were found at overwintering sites in California. Recovered monarchs traveled average distances of 630 to 900 km, demonstrating clearly successful migration (James et al., 2021, Journal of the Lepidopterists’ Society; James et al., 2021, Insects).

More recently, a 2025 study by Matter and colleagues, which used a novel balloon-based flight simulator that lifted monarchs 30 meters into the air, found that wild-derived monarchs reared under autumn-like conditions in a growth chamber displayed southward orientation, larger wing sizes, and partial reproductive diapause, all hallmarks of migratory readiness. This study confirmed that environmental cues during development, not simply whether the butterfly was “wild” or “captive,” are what drive migratory behavior (Matter et al., 2025, bioRxiv/PNAS).

2. Rearing Conditions Matter More Than the Fact of Rearing

The research consistently shows that how you rear monarchs matters far more than whether you rear them. A 2020 study by Schroeder, Majewska, and Altizer found that monarchs reared under autumn-like conditions, cooler temperatures and shorter day lengths, showed greater flight efficiency and lower post-flight metabolism compared to those reared under summer-like conditions. In other words, mimicking natural fall conditions during rearing produced butterflies that were physiologically better prepared for migration (Schroeder et al., 2020, Ecological Entomology).

Even the 2019 study that raised concerns about captive rearing (Tenger-Trolander et al., PNAS) noted that wild-caught monarchs reared outdoors in autumn oriented south normally. The problems arose primarily with commercially bred populations that had been kept in captivity for many generations, and with butterflies that eclosed entirely indoors without exposure to natural environmental cues.

The practical takeaway is clear: hobbyists who rear wild-sourced eggs and caterpillars, keep them in conditions that reflect the natural season, and provide exposure to outdoor light and temperature cycles are producing butterflies fundamentally different from those in long-term commercial breeding operations. Lumping all “captive rearing” together obscures this critical distinction.

3. Rearing Dramatically Increases Survival From Egg to Adult

In the wild, monarchs face staggering mortality. Estimates suggest that only about 2–5% of eggs survive to become adult butterflies, with some researchers citing mortality rates as high as 99% (WWF-Canada, 2014). Predation, parasitism, weather, and disease take an enormous toll at every stage.

By contrast, careful rearing under controlled conditions routinely achieves survival rates of 80–90% or higher from egg to adult (Pleasants, 2017). This represents a dramatic, multi-fold increase in survival. When you protect a caterpillar from tachinid flies, stink bugs, and paper wasps, you are not “interfering with natural selection” in any meaningful population-level sense—you are giving that individual a chance to join the migratory population instead of becoming a statistic.

A citizen-science study also found that monarchs raised on swamp milkweed (Asclepias incarnata) showed particularly strong growth and survival rates, suggesting that host plant choice during rearing can optimize outcomes (Pocius et al., 2018, Environmental Entomology).

4. Rearing Is Not a Significant Threat to the Monarch Population

A comprehensive 2024 review of the western monarch population by entomologist Dr. David James of Washington State University examined all major stressors facing monarchs and concluded that human interference—including capture and rearing—“likely has the least impact on monarch populations” compared to the real drivers of decline. Those primary drivers are neonicotinoid insecticides, habitat loss, climate change, and severe winter storms (James, 2024, Insects).

To put the scale in perspective: even if every hobbyist rearer in North America collectively produced 500,000 monarchs in a given year, that would represent less than 0.1% of the estimated 300-million-member migratory population (Pleasants, 2017). The notion that home rearing is a significant driver of population decline simply does not hold up against the numbers.

Major conservation frameworks agree. The Western Association of Fish and Wildlife Agencies’ monarch conservation plan does not identify personal rearing as a primary threat. And the U.S. Fish and Wildlife Service’s own proposed Endangered Species Act listing (December 2024) specifically includes an exemption allowing individuals to collect, rear, and release up to 250 monarchs per year—a clear acknowledgment that small-scale rearing is compatible with conservation (USFWS Proposed 4(d) Rule, 2024).

5. Urban and Resident Monarchs Are Not Harming Migratory Populations

Another common concern is that monarchs living year-round in urban gardens on non-native milkweed are somehow draining or contaminating the migratory population. A 2025 study from UC Davis directly tested this hypothesis and found no support for it.

The researchers surveyed East Bay neighborhoods over two years, counting milkweed plants, eggs, caterpillars, and adults, and testing butterflies for the OE parasite. They found that resident urban monarchs are essentially disconnected from the migratory population and are not acting as a population “trap.” As senior author Elizabeth Crone put it, these resident populations are “a bit of a red herring” as a cause of migratory decline. The study concluded that urban ecosystems can contribute positively to monarch conservation without harming migratory populations (Erickson et al., 2025, Ecosphere).

6. Monarchs Are Remarkably Resilient

Research has shown that monarchs can tolerate a range of stressors without the dire fitness consequences sometimes attributed to captive conditions. For example, a study on road salt exposure found no measurable effects on wing coloration, survival, body size, immunity, or parasite prevalence, demonstrating the species’ robustness (published in Ecology and Evolution, 2019).

Similarly, the western monarch population’s remarkable rebounds—from fewer than 2,000 butterflies in 2020 to over 330,000 in 2021, demonstrate a species with enormous reproductive resilience when conditions align. This capacity for rapid recovery further argues against the idea that small-scale rearing is a meaningful drag on the population.

7. The Educational Value of Rearing Is Real and Important

Rearing is not just a pleasant hobby, it is one of the most effective tools we have for building the next generation of conservationists. James (2024) states plainly that “the rearing of monarch caterpillars, particularly by children, is an important human link to nature that has positive ramifications for insect conservation beyond monarch butterflies and should be encouraged.”

The Royal Society of Canada (2021) similarly notes that indoor rearing “arguably goes a long way towards awareness and education” and creates “deep and meaningful learning opportunities.” Research on citizen science programs like the Monarch Larva Monitoring Project has shown that participants report increased conservation awareness and increased local conservation activism (Lewandowski & Oberhauser, 2017; Kountoupes & Oberhauser, 2008).

In an era when children spend less time outdoors and the “extinction of experience” with nature is accelerating, raising a monarch from egg to butterfly may be one of the most powerful entry points into environmental awareness that exists. Telling people to stop doing this, without strong evidence of population-level harm, risks losing the very advocates monarchs need most.

8. What About the Concerns?

Legitimate concerns about rearing do exist, and responsible rearers should take them seriously. The key risks identified in the literature include the spread of the OE parasite if hygiene practices are poor, the possibility of reduced fitness in monarchs reared for many generations in continuous captivity (as in commercial operations), and the theoretical risk of disrupting local genetic adaptation if butterflies are moved long distances before release.

However, every one of these risks is manageable through straightforward best practices: testing for OE and sanitizing equipment, rearing wild-sourced (not commercially purchased) eggs and caterpillars, keeping butterflies in conditions that reflect the natural season, providing exposure to natural light and temperature cycles, rearing at small scale and releasing locally, and avoiding rearing on tropical milkweed in regions where it does not go dormant.

None of these concerns justify a blanket condemnation of all rearing. The science distinguishes between responsible hobbyist rearing and multi-generational commercial breeding, and the two should not be conflated.

The Bottom Line

The peer-reviewed literature does not say “stop rearing monarchs.” It says rearing conditions matter, commercial multi-generational breeding is different from hobbyist rearing, reared monarchs can and do migrate when given natural cues, the population-level impact of hobbyist rearing is negligible compared to pesticides, habitat loss, and climate change, and the educational and conservation engagement benefits are real and significant.

The next time someone tells you that “science says rearing is bad,” ask them which study they mean. Ask whether it was about commercially bred monarchs or wild-sourced ones, whether the butterflies were tested in a laboratory simulator or tracked in the actual wild, and whether the study accounted for rearing conditions. The answers matter, and they usually tell a different story than the headline.

Monarchs need every advantage they can get: they need habitat, plenty of milkweed, fewer pesticides, and, most importantly, they need people who care enough to learn about them, protect them, and advocate for them. Responsible rearing is part of that picture, not a threat to it. And this is our sub position.

Literature Cited

  • Erickson, E., Schultz, C., & Crone, E. (2025). Neither source nor trap: Urban gardens as habitat for nonmigratory monarch butterflies in Northern California. Ecosphere, 16, e70259.
  • James, D. G. (2024). Monarch butterflies in western North America: A holistic review of population trends, ecology, stressors, resilience and adaptation. Insects, 15(1), 40.
  • James, D. G., Schaefer, M. E., Kajiura, K. K., & Seymour, T. (2021). Contributions of captive-reared monarchs to the overwintering population in California. Journal of the Lepidopterists’ Society, 75(3), 211–219.
  • James, D. G., et al. (2021). Further insights on the migration biology of monarch butterflies, Danaus plexippus (Lepidoptera: Nymphalidae) from the Pacific Northwest. Insects, 12(2), 161.
  • Kountoupes, D. L., & Oberhauser, K. S. (2008). Citizen science and youth audiences: Educational outcomes of the Monarch Larva Monitoring Project. Journal of Community Engagement and Scholarship, 1(1), 10–20.
  • Lewandowski, E. J., & Oberhauser, K. S. (2017). Contributions of citizen scientists and habitat volunteers to monarch butterfly conservation. Human Dimensions of Wildlife, 22(1), 55–70.
  • Matter, S. F., Parlin, A. F., et al. (2025). Environmental, developmental, and genetic conditions shaping monarch butterfly migration behavior. Proceedings of the National Academy of Sciences [bioRxiv preprint 2025.01.16.633431].
  • Pleasants, J. (2017). Impact on the monarch population depends on the proportion of reared monarchs brought in at each stage. Right of Way.
  • Pocius, V. M., Debinski, D. M., Pleasants, J. M., Bidne, K. G., & Hellmich, R. L. (2018). Monarch butterflies do not place all of their eggs in one basket: oviposition on nine native milkweed species. Environmental Entomology, 47(5), 1135–1146.
  • Royal Society of Canada. (2021). Monarch butterflies raised in captivity can still join the migration. Voices of the RSC.
  • Schroeder, H., Majewska, A., & Altizer, S. (2020). Monarch butterflies reared under autumn-like conditions have more efficient flight and lower post-flight metabolism. Ecological Entomology, 45(3), 562–572.
  • Tenger-Trolander, A., et al. (2019). Contemporary loss of migration in monarch butterflies. Proceedings of the National Academy of Sciences, 116(29), 14671–14676.
  • Tenger-Trolander, A., & Kronforst, M. R. (2020). Migration behaviour of commercial monarchs reared outdoors and wild-derived monarchs reared indoors. Proceedings of the Royal Society B, 287, 20201326.
  • U.S. Fish and Wildlife Service. (2024). Proposed rule to list the monarch butterfly as threatened under the Endangered Species Act, with 4(d) rule. Federal Register, December 12, 2024.
  • Wilcox, A. A. E., Newman, A. E. M., Raine, N. E., Mitchell, G. W., & Norris, D. R. (2021). Captive-reared migratory monarch butterflies show natural orientation when released in the wild. Conservation Physiology, 9(1), coab032.
  • WWF-Canada. (2014). Wild about Butterflies.

r/MonarchButterfly Jun 28 '26

New Community Rule: In this sub, we do not demonize the responsible rearing of monarch butterflies

13 Upvotes

Rearing monarch butterflies is constantly being attacked, but research indicates that, if done responsibly, not only does it not harm wild monarch populations, but it could actually help them.

Read our sub's position here: https://www.reddit.com/r/MonarchButterfly/comments/1ui59g7/what_the_science_actually_says_about_rearing/

This rule applies to posts and comments.


r/MonarchButterfly 2h ago

Update on tiny cocoon! She’s free!

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31 Upvotes

I had the itty bittiest cocoon I’ve ever had and was worried she was sick. Turns out she’s just really tiny! She hatched today and her wings are only about an inch and a bit long each. She’s not 100% dry yet but I will release her later today while it’s sunny but not as blistering hot as it is right now.


r/MonarchButterfly 4h ago

It’s sooo freaky but I can’t look away!

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21 Upvotes

I got to watch the one on the left first and then recognized that the one in the middle was getting ready to do same so I set up my phone to catch this! There’s actually another one in the back going at the same time too you can kinda see the movement between the leaves. Very exciting, it’s my first time doing this!

I have two though that made their cocoon on the underside of leaves as opposed to the top of the enclosure. I still have small caterpillars eating leaves and am concerned about them eating the leaves of the chrysalis? Is there something I should do? should I move the chrysalis?

Thank you for any advice 🐛🦋💛


r/MonarchButterfly 3h ago

Monarch bebes in Raleigh, NC!!!

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13 Upvotes

r/MonarchButterfly 8h ago

What is the thing next to this caterpillar?

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34 Upvotes

r/MonarchButterfly 3h ago

Are they gonna be ok?

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5 Upvotes

I'm getting really worried, it's been a little over a week for the chrysalis on the mesh container that's turning darker and around 4 days for the chrysalis on the plant that's got some brown, they are both monarch caterpillars and they were doing so well, is it because it's to humid? i really hope i didn't fail them 😔


r/MonarchButterfly 7h ago

I found my first cocoon after 4 years of having a butterfly garden!

8 Upvotes

r/MonarchButterfly 8h ago

Viable?

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4 Upvotes

Is this chrysalis viable? It looks off, with brown spotting and a hole in the center.


r/MonarchButterfly 3h ago

Advancing the form/technique

0 Upvotes

No where on the internet can you read about advancing Monarch cultivation technique. I am on grandchildren going on great. People think you cannot get a released Monarch to lay eggs on your plants. Of course you can. I have done multiple generations since May. My goal is to keep a chain going for 2 years nonstop here in Florida. OE and ants farming aphids are the two biggest challenges. The ants farm aphids on my plants and eat ALL the caterpillars before 3rd instar.

Almost all my eggs come from butterflies I release. I raise them inside. I move potted plants with eggs into an ant free environment inside. Then keep the cats separated 5-7 max to cut down on OE spread. There is a huge egg influx the first 2 weeks after release. I collect those and any 1st and 2nd instars I see.

I am preparing for winter. When the ants go seasonally away I expect to get a mass eat out of my inground plants. It will be hundreds at once if they eat all my inground plants. This will be done through releasing egg layers. I will be growing what I call Florida Tall Poppies (tithonia torches) in pots for winter nectar. They will get frosted and killed outside and I want to have a nectar source in winter. Wish me luck I havnt heard of anyone else doing this. They probably do but dont put it on the internet or I cant find it


r/MonarchButterfly 1d ago

Forte enclosed successfully today and I'm THRILLED!

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58 Upvotes

She's beautiful and while I worried she was the cause of the parasites, turns out she was beautiful and I think healthy. She looks healthy. But she was hopping around ready to go and I let her go earlier today! She got on my hand eventually and I got her out of the enclosure and she went flying off :) clear up into the sky and off past our oak tree so I have a lot of hope.

In an insane twist, the one that I dropped might have been the culprit! He's covered in spots today all over and definitely dead now. I put the original isolated one into a tent just in case Vivace makes it, but I've given up on my egg Mezzo. Coda, the smallest of my newer two egg clutch is like.... Gone? IDK what happened he's literally gone. Crescendo is doing great. They were the same size almost. I am confused. I saw some spider corpses in a corner of their enclosure. I'm wondering if one got in and ate him? Really confused. But crescendo is doing amazing and I'm stoked.

No feeling like the feeling of my first release. She was so PRETTY!

Edit: phone corrected eclose to enclose darnit


r/MonarchButterfly 4h ago

Criar mariposas

1 Upvotes

Quiero criar mariposas por primera vez! Que compro de starter pack? Que me aconsejan??
Balcon piso 10 mirando al norte, sol todo el dia. sin viento ni árboles cerca


r/MonarchButterfly 9h ago

Caterpillars Hanging in Not Safe Place

2 Upvotes

For some reason one of my caterpillars decided to hang from a half eaten milkweed leaf on a clipped stalk. I had flamed the stalk so it will last a bit but I don’t think long enough for him to emerge. I also have an eating caterpillar who is on the smaller side. Should I move the chrysalis once it forms and hardens?


r/MonarchButterfly 23h ago

Does this J look okay?

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24 Upvotes

This guy climbed up onto the siding above our milkweed plant and dropped into its j shape today. We usually have around 30-50 caterpillars on our plants this time of year, and always bring a few inside, but we very rarely are able to spot the chrysalises outside, so I was super excited! But I feel like his j shape is a little less... curled up? than the ones we've raised inside. Does it look okay/normal? Am i overthinking? Anything I should do to protect it, since it is a bit exposed on the side of our house? Any insights or advice appreciated!


r/MonarchButterfly 19h ago

Is this Black Death?

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5 Upvotes

This is my first caterpillar, day 15. This morning I believed he was molting. But now early evening, I don’t think he looks well. Is this the worse case scenario I feared? Or does he just have thicker black stripes? Including pictures from earlier in the cycle.


r/MonarchButterfly 1d ago

Share your silly cat pics of the season🐛♥️

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33 Upvotes

I didn't realize how I could be so amused just by watching them eat, but they really are so goober looking and silly some times. Like in Pic 1 the way it hangs 😂 Pic 2 the little ham was in resting position like that. Share some photos if you have any!


r/MonarchButterfly 19h ago

Little lady! First female and she’s very small

5 Upvotes

First female emerged today, and she’s quite small compared to the males. In northern Ontario it’s getting colder (around 10c at night) which made me think this one jumped to J a bit too soon?

Otherwise she seems healthy! She’s outside in some cover as we’re between storms but tomorrow morning looks good for a release. Let’s wish her luck on her big flight south.


r/MonarchButterfly 1d ago

Episode 2 of they could be anywhere

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31 Upvotes

r/MonarchButterfly 1d ago

Today’s batch

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16 Upvotes

Emerged this morning… I think they must be siblings. They will be set for release tomorrow morning.


r/MonarchButterfly 1d ago

Question

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7 Upvotes

First time raising caterpillars. Can someone advise what happened to this chrysalis? The other ones are fine.

Thank you so much!


r/MonarchButterfly 1d ago

Please check!

9 Upvotes

Again, please, please check and check over and over again. Use a magnifying glass if you are checking milkweed leaves for newly hatched eggs, they are almost microscopic in size and u could easily miss them when you toss the leaves in the trash. I take my thoroughly checked leaves and place them in the milkweed patch incase I did miss one. That way instead of the baby dieing in the trash can, he has a chance to live by finding the milkweed. Check both sides of the leaf and in any curls


r/MonarchButterfly 2d ago

Finally caught one in the act!!!

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618 Upvotes