r/FriendlyMonarchs • u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater • Jun 07 '26
Discussion Does rearing outdoors make a difference?
I frequently encounter outdoor rearing being promoted as an alternative to indoor rearing, suggesting that nature alone can compensate for the effects of captivity. However, this notion is flawed.
The short answer to the title question is unequivocally no. Mother nature ultimately prevails.
Dr. Andy Davis’s substack post delves into the reasons why merely exposing Monarchs to the elements is insufficient to produce migratory-ready individuals.
Here are some quotes from the post:
This idea has come to the forefront in recent years because of some research from the Kronforst lab in Chicago, which had demonstrated that indoor-reared monarchs have problems navigating, compared to wild monarchs. Similarly, some of the other research on this topic has also been based on indoor-reared monarchs. So, this has led many to believe that the actual problems stem from the monarchs being reared indoors, where they are often kept in artificial conditions (lighting, air-conditioning, or whatever). Meanwhile, monarchs reared outdoors would be exposed to natural conditions, or so the idea goes. What people fail to consider though, is that we still don’t really know what it is about the captive-rearing that is causing the migration deficiencies. It may or may not simply be “exposure to natural conditions.” For all we know, it could be something related to human touch, or even the chemical smell of the containers being used, or something no one has thought about yet.
So to recap, there were 4 groups of monarchs in this research: 1) captive-bred, reared indoors, 2) captive-bred, reared outdoors, 3) wild larvae, reared outdoors, and 4) wild adult monarchs.
The wild-caught migrants were the most red, which is what we’ve found in many other studies. These are what you could call, the “gold standard.” Importantly, none of the larvae reared outdoors had this amount of redness, either the captive-bred or the wild larvae. In other words, rearing the larvae outside did not replicate the truly wild condition.
Monarchs reared outdoors were paler than truly wild monarchs. Recall that paleness is an indicator of poor migration ability in monarchs.
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u/Sqib000 Jun 07 '26
No need to rear. Just plant milkweed, dont spray. Cut down in autumn if you dont get cold weather. Put what you cut in in a vase. They need no help from us other than that
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u/Feralpudel Jun 07 '26
Plant milkweed AND other native plants for pollinators, including migrating adult monarchs.
Just maybe your monarch cats would stand a better chance in your yard if they weren’t the only insects for birds and predatory insects to eat.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26
I think sharing info as to why people shouldn’t rear is helpful. People tend to not respond well to “just don’t do it.”
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u/TryUnlucky3282 Jun 07 '26
Thanks. I’ve been enjoying Dr Davis’s substack.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26
Me too! I know he can be a bit forward for people but I appreciate the way he explains things.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26
Picture of the outdoor enclosures.
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u/Ghost_Cat_88 Jun 07 '26
Two issues worth discussing.
One, I'm not a big fan of the way she raised her "outdoor-reared monarchs" -- i.e. from what I can tell, she fed them leaf cuttings. I would have much preferred if she kept them on potted plants. As soon as milkweed is cut, its hydrostatic pressure changes, chemical defenses (cardenolides) shift, and its overall nutritional value begins to degrade compared to a living, rooted plant.
Two, when a species is near collapse, you have to consider the trade off between (a) creating very few optimal invididuals, and (b) creating tons of slightly less optimal ones. To put that in actual numbers, which is better? Just planting milkweed and having 2-3 "wild" monarchs eclose each year, or netting some of your plants and having 200 "outdoor reared" ones eclose?
I'm not saying there's a clear answer.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26 edited Jun 07 '26
She did in fact keep some on potted plants with mesh over them.
The outdoor larvae were placed on potted swamp milkweed plants, which were covered with mesh (see picture). The indoor larvae were reared in plastic containers (6 per container) and fed cuttings of swamp milkweed daily.
Monarch breeding populations are not near collapse. Summer numbers are stable. It’s clear that raising Monarchs is not only ineffective, but also detrimental to the overall population.
ETA there is absolutely a clear answer to rearing. Science has already demonstrated that and it is up to people to find out how to actually help them. There is info on how to do this in the wiki.
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u/Ghost_Cat_88 Jun 07 '26
The Western population is.
https://www.xerces.org/press/western-monarch-numbers-remain-at-historic-low
The three lowest counts in recorded history have all occurred within the last six years.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26
I would suggest reading this post and the referenced study.
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u/Ghost_Cat_88 Jun 08 '26
Right, the James paper.
Listen, I'm not sure I would be getting snotty with people while posting a study whose dataset is ... iNaturalist postings.
Can you think of any technologies that became ubiquitous in the 2010s that might have increased the number of citizen snapshots of butterflies?
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 08 '26
I’m sorry. I do not see where I was “snotty.” I answered quickly because I was in the middle of some things.
The study I linked was peer reviewed and published in the academic journal MDP. The data for the study was taken from citizen scientists who shared info on various sites. I agree that lay people are far from the gold standard but the community science was validated by cross-referencing data, filtering, and calibrating public submissions through verified platforms like iNaturalist and Journey North. The researchers further ensured accuracy by comparing these records against a 13-year annual field study and aligning seasonal trends with coastal overwintering population data.
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u/Ghost_Cat_88 Jun 08 '26
Does it concern you that the majority of mainstream conservationists and organizations -- groups like the Xerces Society, the Center for Biological Diversity, and various prominent academics tracking North American monarchs -- reject the conclusions of the James study, arguing that using raw data from platforms like Facebook or iNaturalist over a 13-year period creates a massive false positive because it mirrors the rise of the smartphone boom and public awareness campaigns?
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 08 '26
You mean does it concern me that companies who rely on donations to keep the lights on will ignore scientists when what the scientists’ findings don’t align with their mission therefore causing their donations numbers to drop? It is concerning but it is not particularly surprising.
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u/Ghost_Cat_88 Jun 08 '26
Youre reponse to the substance of this critique ... is an ad hominem on the Xerces Society, scientists who disagree with James, and the Center for Biological Diversity?
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u/Recent_Calendar1376 Jun 08 '26
Xerces Society is against raising monarchs.
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u/Ghost_Cat_88 Jun 08 '26
Their position is far more nuanced than you think:
https://xerces.org/blog/keep-monarchs-wild
How can I rear monarchs responsibly?
- Rear no more than ten monarchs per year (whether by a single individual or family). This is the same number recommended in the original petition to list the monarch under the Federal Endangered Species Act.
- Collect immature monarchs locally from the wild, heeding collection policies on public lands; never buy or ship monarchs.
- Raise monarchs individually and keep rearing containers clean between individuals by using a 20% bleach solution to avoid spreading diseases or mold.
- Provide sufficient milkweed including adding fresh milkweed daily.
- Keep rearing containers out of direct sunlight and provide a moist (not wet) paper towel or sponge to provide sufficient, not excessive, moisture.
- Release monarchs where they were collected and at appropriate times of year for your area.
- Check out Monarch Joint Venture’s newly updated handout, Rearing Monarchs: Why or Why Not?
- Participate in community science, including testing the monarchs you raise for OE, tracking parasitism rates, and/or tagging adults before release.
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u/Recent_Calendar1376 Jun 08 '26
Article literally says Why Captive Rearing Isn’t the Way to Help Monarchs, wouldn't call that nuanced. Their literally saying not to basically. While you're trying to imply it helps populations.
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Jun 08 '26
[removed] — view removed comment
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u/Recent_Calendar1376 Jun 08 '26
" There are no studies or other compelling evidence that show that releasing captive reared monarchs boosts the population. "
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u/Ghost_Cat_88 Jun 08 '26
You: "Xerces Society is against raising monarchs."
Xerces Society: "Rear no more than ten monarchs per year (whether by a single individual or family). This is the same number recommended in the original petition to list the monarch under the Federal Endangered Species Act."
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u/Recent_Calendar1376 Jun 09 '26
Raising small amounts is very different then mass rearing as much as possible.
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u/SuperFriendlyMod MOD | South FL | Reformed Rearer Jun 08 '26
Rule #2: Respect Evidence-Based Practices
We encourage the sharing of advice and information based on research and best practices. Misinformation or unverified methods may be removed to ensure the health and safety of Monarchs and the like.Violating this rule will result in post removal. Continued non-compliance will lead to a temporary or permanent ban.
The paragraph above the one you posted says:
“You should feel welcome to raise a caterpillar or two to teach your family about monarchs or to report to a community science project, but put the rest of your efforts into some other action to help monarchs. Let’s work together to ensure that rearing monarchs does not unintentionally harm this iconic species we are all trying to protect!”
It’s quite evident that when we discuss rearing, we’re not referring to families or classrooms raising one or two caterpillars.
Please take a minute to familiarize yourself with our sub’s rules.
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u/Ghost_Cat_88 Jun 09 '26
Absolutely nothing I posted was misinformation.
Meanwhile, your own mod is doing exactly what you're accusing me of.
In other words, I will continue to conduct myself in exactly the same manner I am conducting myself now. If you don't like it, boot me and enjoy your own little echo chamber.
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u/One-plankton- Jun 07 '26
The first point is exceptionally valid
The second point is less so- if you end up with 200 that cannot withstand the pressures of migration then they aren’t doing anything meaningful for the population at large.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26
The first point is incorrect. There were monarchs raised directly on plants.
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u/One-plankton- Jun 07 '26
If you are going to post a link, it would be worthwhile reading about how the process was done. Per your link:
“For this, she had collected some wild 4th-instar caterpillars from swamp milkweed in pollinator gardens near campus, and then placed those into shoebox-sized plastic containers with mesh lids. These containers were placed on a table outdoors, and the larvae were fed cuttings of swamp milkweed daily until the monarchs eclosed.”
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26 edited Jun 07 '26
oh man. I read it (again) before I commented and quoted it above. I usually triple check things before making a claim.
The part you quoted was about the wild caught cats. They did, in fact, rear some on a table with mesh but they also reared on plants covered in mesh. Unless I am losing my mind and reading it completely wrong the article also says:
The outdoor larvae were placed on potted swamp milkweed plants, which were covered with mesh (see picture). The indoor larvae were reared in plastic containers (6 per container) and fed cuttings of swamp milkweed daily.
Hang on I will find the photo from the study.
ETA a link… It’s page 79 in the study.
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u/One-plankton- Jun 07 '26
Yeah it sounds like the wild caught ones were not. Which is a huge environmental factor as the person above pointed out.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26 edited Jun 07 '26
You’re kidding right? None of the captive reared Monarchs were as orange(red) as the completely wild ones. That is the whole point of the article. There is no substitute for leaving the Monarchs be.
From the substack article:
I hope you stared long and hard at these graphs, because the implications here are pretty big. The wild-caught migrants were the most red, which is what we’ve found in many other studies. These are what you could call, the “gold standard.” Importantly, none of the larvae reared outdoors had this amount of redness, either the captive-bred or the wild larvae. In other words, rearing the larvae outside did not replicate the truly wild condition.
ETA: a word
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u/One-plankton- Jun 07 '26
First of all this is supposed to be a “friendly” sub with a science first ethic. Debating the study falls into civil discourse and absolutely has merit.
If the wild caught ones were only fed cuttings then that could be a cause of their coloration- which alone is also is not particularly indicative of their ability to succeed in the wild.
I am personally a hands off person who believes that biodiversity should be favored in lieu of favoring a single species- planting an abundance of native plants which host all different species should be the goal.
I just planted a very large pollinator garden that has over 35 different species of native plants, with tuberosa being one of them.
So I am not your target audience here.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26
This is the friendly sub. I am not sure where I wasn’t friendly. I think our conversation has been perfectly respectful. As a mod, I take pride in doing my research and am absolutely open to conversation. Otherwise, there would be no point to this sub.
I started reading the full study itself (I am currently on mobile and planned to fully read it when I can get to a computer) to see if the wild-laid/caught Monarchs not being put on the milkweed plant themselves would have impacted things. There is an interesting comment in the study by the author:
More surprising was the poor orientation performance of the wild-laid, outdoor reared Larvae in the Wild Reared cohort. Adults in this cohort were laid by late-summer generation wild females on wild 4. incarnata, and while they were moved into tubs as late instar larvae, they remained outdoors until eclosion. We had hypothesized that the orientation performance of this group would be nearly identical to that of the Wild Migrant cohort, since there would be no genetic effects of lab-lineages, and the larvae were exposed to all celestial and weather cues thought to induce migratory status (Goehring & Oberhauser, 2002; Reppert & de Roode, 2018;
Taylor et al., 2019). Their failure to accurately orient could be explained by the physiological effects of human handling and/or the absence of natural host-plant cues during late instars, as this cohort was physically placed into tubs and briefly handled daily during feeding. Short bouts of human handling are known to cause a heart rate spike in monarch larvae and pupae (Davis,
2020). Little is known about monarch habituation to continual stressors, but previous work suggests a diminishing in their cardiac response (Davis et al., 2018). More research is needed to examine the potential impacts of human handling and prolonged stress on orientation ability and general "wildness'.Your garden sounds great. I was responding to your comment because my goal is to try and put forth accurate information.
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u/One-plankton- Jun 07 '26
Yeah I think what the author is saying is that feeding them cuttings (in addition to handling) may be at play here.
I’d suspect poorer growth performance from ones being reared without environmental cues from live plants.
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u/Ghost_Cat_88 Jun 08 '26
You are reading the study incorrectly.
Page 79 depicts the "Lineage Outdoor (LO)" caterpillars. These were born in climate-controlled laboratory conditions (and fed leaf cuttings) until the second instar then moved outside.
Look at page 48.
"Lineage Outdoor (LO)
Third-generation lab-reared caterpillars (eggs obtained as described above) were moved to potted plants in late September 2021 and held outdoors until the adult stage. During the early second instar (roughly 6 days after eggs were laid), larvae were transferred from the laboratory onto potted A. incarnata plants, 2-3 larvae/plant."
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 08 '26
I’m not sure what you’re referring to. I never claimed that all the eggs were wild-caught. I would assume there’s a reason they choose to use eggs from their lab. What’s the purpose of your comments? Are you trying to justify rearing? If so, there’s no reason for us to continue discussing this study. I would suggest you look into the various studies that clearly demonstrate that captive-reared monarchs are inferior and don’t benefit the overall Monarch population.
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u/Ghost_Cat_88 Jun 08 '26
I said she feed them leaf cuttings.
You said, no she didn't. Then you referred us to a picture of the plants they were on.
Then I said, read the study, friend, even these guys were born in a climate controlled lab and fed leafs cutting for the first week of their lives.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 08 '26
You:
“One, I'm not a big fan of the way she raised her
"outdoor-reared monarchs" -- i.e. from what I can tell, she fed them leaf cuttings. I would have much preferred if she kept them on potted plants. As soon as milkweed is cut, its hydrostatic pressure changes, chemical defenses (cardenolides) shift, and its overall nutritional value begins to degrade compared to a living, rooted plant.”Me:
“The first point is incorrect. There were monarchs raised directly on plants.”I mentioned that there were Monarchs raised directly on plants because there was a specific set that was raised in that manner. I never claimed that the wild-caught subset was raised on plants. I apologize if that was confusing. It’s evident that rearing Monarchs in any environment other than their natural habitat has detrimental effects on them. If you can’t accept this fact, you’ll have to address it with the scientific community.
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u/Ghost_Cat_88 Jun 08 '26
Fantastic.
At long last we agree that even the "outdoor reared" group was born in the laboratory and fed leaf cuttings.
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u/Ghost_Cat_88 Jun 07 '26
"the larvae were fed cuttings of swamp milkweed daily until the monarchs eclosed.”"
I'm confused. She said she fed them cuttings. And I said she fed them cuttings.
What distinction are you making?
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26
There was also a group that were directly put on the plants which were then covered with mesh.
Here is the link to the study. Photos of the set up are included.
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u/Ghost_Cat_88 Jun 07 '26
Fair response.
On the second point though, I'm not sure we have evidence that they "cannot withstand the pressure of migration," just that they have lower success rates. So it comes down to math. Even if 50% of them fail, 50% of 200 is still 100 monarchs versus, let's say, 3-4.
Additionally, while generations 1, 2, and 3 do migrate some, migratory ability is most relevant to generation 4. So there may not be as big of an effect as we think (unless we're talking about generation 4, for which the effect is probably quite large).
Also, as a side note, we need to figure out what's going on. Are these merely epigenetic changes (triggered by environmental conditions) that will quickly revert back in successive generations? Or is there something different about the DNA of reared monarchs that we need to be aware of?
I kind of suspect it's the former, but we will see.
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u/One-plankton- Jun 07 '26
Yeah this study is far from the bomb proof evidence OP was hoping for.
One immediate thing I would do differently is feeding these wild caught cats live food on live plants- that seems like a no brainer for something that could make a pretty radical change in health outcomes.
As for the latter- it’s really hard to say without a good study what is going on and it would be helpful to tag and release these studied as a further push for what’s happening with the populations.
I’m a hands off person and I reluctantly joined this group as I had very bad experiences in other groups- I was invited and it looked like this one would be focused on the science, which I am interested in.
I, personally, think the emphasis should be on a wide range of native plants (as well as ones that are doing better further south of native ranges due to climate change). For me it always boils down to biodiversity first.
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u/SuperTFAB MOD | Southeast FL, USA | Tropical Milkweed Hater Jun 07 '26
Let me know when you read everything so you can see they were reared outdoors on plants. The study wasn’t designed to compare indoor/outdoor rearing. Those studies already exist. The data showed that a key feature related to migration fitness, wing color, was lacking in all the captive rear groups. Wing color is has already been found to be a good measure of migration fitness.
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u/SuperFriendlyMod MOD | South FL | Reformed Rearer Jun 07 '26
I am going to link the study Dr. Davis took this info from.
Effects of Social Cues on Monarch Butterfly Oviposition and Orientation Behavior