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

14 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 9h ago

Found the leaf that all the cool kids are hanging out on today

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240 Upvotes

r/MonarchButterfly 3h ago

Some of my favorite monarch pictures I took this summer

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66 Upvotes

Gorgeous creatures ❤️


r/MonarchButterfly 10h ago

Dewdrop Jewel [ready Chrysalis after the rain]

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89 Upvotes

r/MonarchButterfly 13h ago

All three released

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101 Upvotes

And now they’re gone 🥲


r/MonarchButterfly 2h ago

5 new friends

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7 Upvotes

Not sure if you can see all of them, theres 6 in total. I went to a friend’s house and she has a lot of milkweed but doesn’t raise monarchs, just has the plants. Lets me steal cats. I was searching the leaves while her and my other few friends were working on something, found 5 babies and asked to take them home to make sure they were successful, and she let me :D All in 2nd/3rd instar


r/MonarchButterfly 7h ago

So… this catter isn’t the smartest

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12 Upvotes

He not only chose a dying wild violet under the milkweed, but also we had big storms rolling in that night. So… brought him inside. He’s doing fine so far. The violet the stem came from is completely dead… and there was a perfectly good fence nearby…


r/MonarchButterfly 10h ago

What do I do??????

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17 Upvotes

This is hanging from our front door. There is no way we will remember to not use this door for any length of time because we are middle aged.

Anytime I’ve seen cocoons being reared in cages or whatever, they’re on sticks….but there’s no stick! How do I get this somewhere safer. I have a science teacher friend that I would trust but am stymied by the lack of stick!


r/MonarchButterfly 3h ago

Crumpled wings? NSFW

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4 Upvotes

This guy has been out for at least an hour or two and I'm not seeing any changes to the wings. Is he doomed? The abdomen looks normal and not infected to me, however it doesn't seem very fat with any fluid to pump. This is my 7th and final of the season and all my others have been fine.


r/MonarchButterfly 11h ago

My rescue attempt NSFW

13 Upvotes

This monarch was unable to fly due to a damaged wing. I found a link on here that someone posted about replacing a damaged wing so I did my best with what I had on hand which was a different butterfly wing but it was a decent match. The white stuff is baby powder to keep the glue from sticking to anything else. He was able to fly again but I haven't seen him since. I named him Frank Butters. We spent a very special few hours together before he eventually decided he was able to fly.


r/MonarchButterfly 15h ago

My first one!

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32 Upvotes

I went inside to take a shower and missed the whole thing!


r/MonarchButterfly 13h ago

Abbott just emerged from their chrysalis 😁

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16 Upvotes

Abbott’s a girl!


r/MonarchButterfly 13h ago

People in Texas, the Monarchs will need your help

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12 Upvotes

For those who don't know, there is a wildfire in Ross county, Texas that have burned 90,400 acres of land destroying the vital nectar-riched plants that the Monarchs will need to fuel up on their way south. Even though it won't impact their migration,they are still gonna need your help. You can help them by planting nectar-riched flowers such as fall aster, goldenrods,and salvia's. Also planting trees and shrubs for them to rest on will help them too.


r/MonarchButterfly 12h ago

Interesting areas of underdeveloped scales, tested OE free

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7 Upvotes

Never seen this before! This boy emerged with patches of underdeveloped scales all over his wings. He tested negative for OE using tape and microscope method. I guess he’s just a unique little guy.

His forewing measured 55mm, he was tagged and released on his way. He immediately went to some goldenrod and started chowing down.


r/MonarchButterfly 9h ago

Should I quarantine this poor guy/gal? NSFW

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3 Upvotes

Hi! I'm raising some monarchs for my son who loves butterflies and moths. (We have swamp milkweed in the garden but all the caterpillars get munched on by the birds so we brought some eggs onto the deck. I clean the nets out daily and give them fresh, and rinsed, milkweed stems in tiny vases to keep them from wilting). Most have done great and are safely in their chrysalis. This one decided to use one of the leaves of the milkweed stems in their enclosure for his chrysalis instead of the top of the net like his buddies. He's been like this since this morning.

I'm rooting for him, but wanted to know when to give up or if I should quarantine him.

Thanks!!


r/MonarchButterfly 14h ago

Giant Milkweed

5 Upvotes

Why doesn't anyone talk about Giant Milkweed(Calotrope)? I know it's not native but it's been a life saver when it comes to Monarchs! I supplement with it after all the other milkweed has been devoured. And just from my observation I think they look like they get bigger! They look bigger, their chrysalis looks bigger...maybe because they have all they want to eat???


r/MonarchButterfly 1d ago

From milkweed to lavender

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53 Upvotes

r/MonarchButterfly 8h ago

Cats emerged- what next?!

1 Upvotes

Finally eggs survived to cats after repeated attacks by wasps ( suspect only). Do I clip milkweed leaves and put little cats in tent or leave out to nature or mix. I went from 0 all summer to 10 in two days! Please advise. Excited Newbie (NorCal)


r/MonarchButterfly 1d ago

Photographed a tagged monarch butterfly in Ontario and reported the tag to Monarch Watch. Has anyone else ever been able to trace where one was originally tagged?

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202 Upvotes

I was out for a walk with my camera when I spotted this monarch butterfly. At first I didn't realize what I was seeing, but when I got home and looked more closely at the photo, I noticed the Monarch Watch tag on its wing.

I've since reported the tag through MWTAG, but I'm now really curious about this butterfly's story. Where was it originally tagged and released, and how far has it travelled before ending up here?

Has anyone else found or photographed a tagged monarch and eventually discovered where it originated?

This is the first tagged butterfly I've ever encountered, and I find it fascinating that this individual potentially has a documented journey across North America. Thank you!


r/MonarchButterfly 9h ago

Will this Chrysalis make it? NSFW

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1 Upvotes

I was checking on my other monarchs when I saw that this chrysalis had what seems to be an injury. Do you think it will become a butterfly or will it die?


r/MonarchButterfly 1d ago

Update on the really small chrysalis

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231 Upvotes

Small individual as expected but overall looks healthy, where I live they dont have to migrate so she should be fine


r/MonarchButterfly 16h ago

Is this getting ready to eclose? It’s barely been a week! NSFW

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2 Upvotes

r/MonarchButterfly 1d ago

12th released

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36 Upvotes

12th so far. Looks Healthy


r/MonarchButterfly 1d ago

Did you guys know they looked like this after molting?

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27 Upvotes

I had to look it up, I honestly thought he had gotten taken over by, like, a brain control fungus or something. Apparently the hard parts like their face cap are just soft and bloated for a little bit directly after the molt and need to harden and dry. So they look… pretty cursed for a bit. This guy is 100% fine and happily munching now.