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.

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/

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