u/SuperFriendlyMod

In this post I will be discussing point numbers 5 and 6.

While researching information for these posts I noticed Google's algorithm is linking the other post and presenting it as fact which is what I was afraid would happen. I have changed the title of this series, as well as the format, in an effort to hopefully have Google's SEO grab onto these posts. I have a rudimentary understanding of how this all works so let me know if you have any ideas.

A Warning: Please do not go to the other sub to harass anyone, including the mod. I don’t want to be accused of breaking Reddit's rules against brigading. Plus, dissenting opinions there usually get banned with no warning anyway, and that wouldn’t help anyone.

Using AI: I also want to urge everyone not to use AI as your primary research tool. AI isn't a search engine built to find absolute facts. It is a pattern-prediction tool designed to generate text that sounds convincing. If you ask it a biased question, it will confidently compile an answer that looks perfectly right, even if the underlying facts are completely wrong.

>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).

The study cited in this paragraph is entitled:Neither source nor trap: Urban gardens as habitat for nonmigratory monarch butterflies in Northern California. It is very important to note that this study was done on the Western population of Monarchs. This is mentioned more than a few times in this study and in the press release related to the study. These two paragraphs may be the only true parts of the whole other post. The problem lies with the fact that beyond mentioning that the study was done in the East Bay there was no indication in the post that the information that was being presented doesn't apply to all Monarchs.

Here is what the study had to say about the eastern population:

>There is some evidence that urban gardens with evergreen milkweeds attract migratory monarchs. In a lab and field study in the southeastern United States, exposure to A. curassavica induced migratory adults to break reproductive diapause during fall migration (Majewska & Altizer, 2019). Similarly, over 50% of collected individuals at year-round breeding sites during fall were likely migratory monarchs, and migratory monarchs in urban gardens were more likely to be reproductively active (Satterfield et al., 2018). This behavior suggests that, at least in the eastern popula- tion of North American monarchs, some individuals leave the migration to join resident populations. In line with the hypothesis of an ecological trap, nonmigratory monarch populations tend to have higher levels of Ophyrocystis elektroscirrha (OE) (Majewska 2 of 14 ERICKSON ET AL.

There are numerous studies on this topic concerning the eastern population. I encourage those who plant non-native tropical milkweed and rear monarchs to do a Google Scholar search to read these studies for themselves. During my search Google's AI utilized incorrect information 100% of the time including using the rearing post from Reddit as fact.

>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.

I had to search for this study myself because although the post had the year and the general website the "cited" section of the other post lacked his particular citation. The study that was vaguely referenced was this one: The potential of roadside verges as insect habitat: Road salt has few effects on monarch butterfly performance and migration.

I think it is wild to say that Monarchs are Remarkably Resilient in a post about rearing while using their decline as an excuse to rear them. This study only tested the Monarchs reaction to road salts in various quantities. This is what it actually said:

>While the present study focused on salt as a possible toxic risk of roadside plants, it is important to note that there are other risks in roadside habitat, including metal exposure (Shephard et al., 2021) and collisions with vehicles (Alvarez et al., 2019); levels of heavy metals in most roadside milkweeds appear in safe limits to monarchs (Shephard et al., 2020,2021), but the overall risks of collisions are less clear. Collision rates vary with topography, traffic speed, species, and other factors (Alvarezet al., 2019; McKenna et al., 2001), leaving many unknowns in estimating mortality during the breeding season in our study region, and pointing to roadside mortality as a key area for future research.

The next paragraph argues that the western population went from fewer than 2,000 butterflies in 2020 to over 330,000 in 2021 in order to prove that the Monarchs are resilient. There was no citation for this claim but I came across it while reading info for these posts. I'm sure that after reviewing the first four points that I don't have to tell you that this sentence is misleading. The numbers and years are correct. What isn't correct is using those numbers to convey the idea that rearing won't do any harm. From the Xerces post itself:

>Once, millions of monarchs overwintered annually along the Pacific coast in California and Baja California. But by the mid-2010s, the population had declined to hundreds of thousands of butterflies, a more than 95% decline from the 1980s. In 2020, the annual Western Monarch Count tallied less than 2,000 monarchs. Although the population has fluctuated between a few thousand to over 200,000 in the years following, it remains perilously small and vulnerable to yearly changes.

>While the annual ups and downs of the population garner a lot of attention, the real issue is the long-term population decline due to stressors such as habitat loss and degradation, pesticides, and climate change—as well as other pressures on the migratory cycle of the monarch that we have yet to fully study or comprehend. There are no quick fixes to solve these large and complex forces, but we can all take actions both big and small to help save monarchs.

That article's call to action lists 5 things that can be done to help the Western population of Monarchs:

>

>2. Protect monarchs and their habitat from pesticides

>3. Protect and manage California overwintering sites

>4. Spread the word about monarch and pollinator conservation

>5. Participate in community science.

Not one of those suggestions includes rearing. Nor do the dozen or so studies I read.

Everybody have a great and safe holiday weekend. I will be back with points 7 and 8 although I think I've proven the point in the last 4 parts that I posted. Thank you for all your support.

I’m addressing the claims from that rearing post point by point because the amount of cherry-picking and misrepresentation of science is just too massive to ignore.

It’s going to have to be more than one post because there is a lot of information to go through and it’s getting late.

A Warning: Please do not go to the other sub to harass anyone, including the mod. I don’t want to be accused of breaking Reddit's rules against brigading. Plus, dissenting opinions there usually get banned with no warning anyway, and that wouldn’t help anyone.

Using AI: I also want to urge everyone not to use AI as your primary research tool. AI isn't a search engine built to find absolute facts. It is a pattern-prediction tool designed to generate text that sounds convincing. If you ask it a biased question, it will confidently compile an answer that looks perfectly right, even if the underlying facts are completely wrong.

Need to know: A metabolic rate (MR) is how quickly the monarch burns energy.

As with the previous post I will take each point directly from the other post, add the citations, and discuss the misleading or incorrect information.

>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).

The 2020 study from Schroeder did in fact prove that if you raise Monarchs in tightly controlled laboratory environments that mimic autumn and summer conditions that you can see the metabolic differences in the two. Those raised in the environment consistent with autumn conditions had a lower metabolic rate than those raised in summer conditions. This does not mean that mimicking autumn or summer conditions will give you Monarchs who are better prepared for migration. It does not prove that these indoor-reared butterflies are physically equal to wild migrants. It only shows the difference in the MR.

In fact in this study the authors point to the 2019 study by Tenger-Trolander that we went over in the last post. They write, "monarchs reared in indoor environments mimicking autumn-like conditions showed lower reproductive development, yet failed to orient in a southward flight direction as wild-caught migrants do, indicating that captive conditions such as those used in our study are missing critical cues needed for monarchs to migrate successfully."

>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.

It needs to be noted how those wild caught monarchs were raised. They were raised outdoors, on a rooftop in a small mesh container which was placed in a larger, completely open to the sky enclosure. The only thing tested in this instance was navigation. They did not measure the wing shapes, color redness, or wing size of this specific rooftop generation to compare them to wild migrants. Their sole focus for this group was mapping whether unfiltered skylight kept their internal sun compass from breaking. It does. That's great. Is there a study that tests for these other factors because we know we need a complete package in order to get the best migrants possible?

There is a study that looks at these other factors. A 2021 study from Dr Andy Davis showed that Monarchs raised in an indoor environment that is set up to mimic their natural one were paler, had a more rounded and less elongated wing shape than their wild counterparts. These are things seen in resident populations which don't migrate.

>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.

We already established in the last post that we are not just talking about Monarchs that are purchased commercially. These studies include wild caught, indoor reared Monarchs. I think some people will take the study on navigation and use it as an excuse to rear monarchs outdoors. They firmly believe that it is ok to cover milkweed with mesh enclosures or build full on butterfly aviaries to protect the caterpillars as all costs. Even if this kind of rearing doesn't lead to navigation issues a whole host of other issues comes into play. When you protect the caterpillars at all costs you are artificially keeping weak, genetically unviable individuals alive that nature would have naturally weeded out. You might be increasing the quantity of butterflies leaving your yard, but you are actively degrading the quality of the wild gene pool. More on the importance of predation later.

I will move on to the next point tomorrow. If you are reading these I hope it is clear that the post is misleading at best and intentionally deceptive at worst.

Edited to fix the format. 4:07pm 6/29/26

I’m addressing the claims from that rearing post point by point because the amount of cherry-picking and misrepresentation of science is just too massive to ignore.

It’s going to have to be more than one post because there is a lot of information to go through and it’s getting late.

A Warning: Please do not go to the other sub to harass anyone, including the mod. I don’t want to be accused of breaking Reddit's rules against brigading. Plus, dissenting opinions there usually get banned with no warning anyway, and that wouldn’t help anyone.

Using AI: I also want to urge everyone not to use AI as your primary research tool. AI isn't a search engine built to find absolute facts. It is a pattern-prediction tool designed to generate text that sounds convincing. If you ask it a biased question, it will confidently compile an answer that looks perfectly right, even if the underlying facts are completely wrong.

Must Know: Before diving into the post, we need to establish some basic facts. North America has two distinct monarch populations, the Eastern and the Western, which are divided by the Rocky Mountains. They are the exact same species, but they have entirely different migration routes. The Eastern population flies up to 3,000 miles from Canada and the East Coast down to central Mexico. The Western population takes a much shorter trip from the Pacific Northwest down to the California coast. Their winter homes are in totally different places, which means they fly in completely different directions.

>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.

Let’s break down this first paragraph. This is the study referenced: Contemporary loss of migration in monarch butterflies | PNAS. Has further research complicated things? Yes. Has it contradicted it? No.

This study did not just test commercially bred monarchs. In order for this to make sense, we need to be clear on what types of monarchs were reared and what the control group looked like. The control group consisted of wild-caught, migrating monarchs captured during the summer generation and mid-migration, and they were tested immediately.

The commercial monarchs were mass-bred and purchased as adults in July 2016. They were allowed to mate, their eggs were collected, and the offspring were reared outdoors in mesh cages. This group included both a summer and an autumn generation to compare with the wild-caught monarchs.

Another group consisted of eggs taken from wild monarchs and reared indoors under conditions that directly mimicked the temperature and sun position of their natural environment. A final group of wild-derived eggs was raised entirely outdoors, but brought inside right as they pupated and were close to eclosing.

The adult wild-caught group flew exactly as they should, but every single variable group listed above failed to do the same. The only thing subsequent research proved is that a monarch's navigation system is incredibly fragile.

I also want to point out that during this experiment, there was a delay and a reduction in sample size due to an outbreak of NPV (Nuclear Polyhedrosis Virus). This happened specifically within the wild-derived, indoor-reared group. If a group of professional scientists cannot fully control NPV in a sterile lab, it is illogical to assume a layperson can do better on a kitchen counter. It is highly telling that during a study related to rearing, the rearing itself caused a major disease breakout. This only further proves that even in the best of circumstances, you cannot control everything indoors.

>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).

The Wilcox study took place in Ontario, Canada. For a monarch in Ontario, which is supposed to fly south-southwest toward Mexico, flying south-southeast takes them straight out over the Atlantic Ocean. Generalizing that “97% of the radio-tracked monarchs flew the correct south to south-east direction” makes it sound like a large number of monarchs flew toward safety, but that is not what happened.

In reality, that 97% represents just 28 out of 29 tracked monarchs. They flew at an average bearing of 147 degrees. On a compass, 180 degrees is dead South, and the path to Mexico from Ontario is Southwest at roughly 220 to 240 degrees. Here is a link to a peer-reviewed critique by monarch expert Dr. Andy Davis, which further explains the flaws of this study and shows maps plotting the actual paths these 28 monarchs took. It is also important to note that the Wilcox study did not use a wild control group. It would have completely changed the data if 29 wild-caught, migrating monarchs had been tracked alongside them. Wilcox and company wrote a rebuttal to Dr Davis' critique. (See my comment below)

>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).

This study was done on the Western population of monarchs. Throwing out big numbers like 14,000 tagged butterflies and 900 km flights is misleading if you don’t identify that these monarchs are not the ones making the grueling trip to Mexico. Out of those 14,000 captive-reared butterflies, only 182 were ever recovered. That is a return rate of barely 1.3%.

Because the Western migration route is shorter and geographically easier than the 3,000-mile Eastern trek, a tiny fraction of navigationally compromised butterflies can manage to stumble their way to the coast. Using a 1.3% survival rate on a short, simple route to prove captive rearing is safe for the long Eastern route is completely dishonest. Furthermore, the James study relied on citizens who largely reared these monarchs outdoors in backyard netting, not inside a house.

>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).

The study being referenced was actually done by Hsiang-Yu Tsai, Cristian Molina, John Pleasants and Marcus R. Kronforst. Matter is incorrect. This kind of simple mistake is common with AI. This study has not been peer reviewed yet. The “indoor rearing” was done by using a multi-million-dollar industrial growth chamber to program precise, mathematical drops in light and temperature. A hobbyist cannot replicate this at home. This study doesn't defend home breeding. It proves that a monarch’s navigation system is so fragile that you need a massive lab incubator to simulate autumn indoors, captivity itself destroys their genetics over time, and they can't even use their compass properly at ground level.

If you're new here welcome and please join us for part 2!

If I have to edit this to make changes due to formatting, grammar errors, or for any other reason, I will make that clear down below. I am not a scientist. If you find a mistake please point it out.

Edited on 6/29 9:40am to fix formatting, sentence structure and include the link for the rebuttal paper to Dr Davis' initial critique.

Edited to add Part 2: "Rearing Conditions Matter More Than the Fact of Rearing"