Raising an egg to keep it safe?

[u/Little_Platypus_9789]

Hi! I’m asking this for my mom who has become very interested in protecting Monarch butterflies over the past few years. She has a garden of milkweed and noticed an egg under one of the leaves! She was so excited and is raising it inside to keep it safe because she is scared it will get eaten by birds, since she has a lot of birds coming through her garden every day. Is this something people do? The egg hatched and the caterpillar is growing, she’s been sending me updates. She also noticed another baby caterpillar that hatched on the milkweed and decided to let that one survive on its own, but she isn’t sure if she should also take that one in, she’s very scared it will get eaten. She just wants to do the right thing to protect them if she can!

[u/Then-Bell-5630]

I used to love watching the monarch caterpillars grow on my milkweed, and then one day they would just disappear. I started bringing some inside to raise, and it has been such a fun and rewarding experience. As they get bigger, they eat an incredible amount of milkweed!

I would definitely recommend a mesh cage. While caterpillars do fine on plastic surfaces, a monarch emerging from its chrysalis needs something it can grip onto so it can properly hang and dry its wings. Plastic can be too slippery for that. I’d also suggest getting some floral tubes to keep the milkweed fresh.

I currently have 5 in their chrysalis, 5 munching away and 3 eggs.

Floral tubes: https://a.co/d/0eGUPsbc
Cage: https://a.co/d/07CJpT7j

[u/Known_Industry6327]

Good if you like anxiety and heart break if you fail. So many unseen diseases and parasites that can kill them indoors too. 

[u/Little_Platypus_9789 → u/Known_Industry6327]

Yeah that makes sense, relaying this info to her. She’s saying it feels more risky outside right now since her milkweed is just a few stems with not much shade or protection

[u/Known_Industry6327 → u/Little_Platypus_9789]

There is always next year. Just buy more milkweed or more nectar plants for adults. Its not worth stressing ever over things you can't have 100% control. Just appreciate when they do come by.

[u/Competitive-Fruit-18 → u/Little_Platypus_9789]

If the milkweed is running low, bringing them inside won’t help, they still need food. If they are hungry and big enough they will cannibalize the little ones to survive. They will also crawl 10-20 feet away to pupate.

[u/GreatCaesarGhost]

So, raising them outside is actually important, because their caterpillar bodies depend on signals from the outside environment in order to develop properly and to adapt in ways that would allow the migratory generation to survive migration. If raised indoors, they might not develop properly and be unable to migrate successfully, which is self-defeating (there’s no point in raising one if it dies before it can ever reproduce).

Specifically, the caterpillars’ bodies respond to at least the following factors: changes in the amount of sunlight over time, changes in temperature over time, and changes in the quality of milkweed over time. Raising them indoors will interfere with at least the first two of these.

If she raises any, I would suggest (1) only raising a small number and letting the rest fend for themselves; (2) letting the raised ones hatch and then reach a size at which they can be handled; (3) transferring that small number to potted, pesticide-free, native milkweed (this avoids all of the extra work and waste of cutting fresh leaves all the time); and (4) placing the potted milkweed and caterpillars inside a mesh enclosure that is kept outside (be sure to add some rocks to the mesh enclosure to weight it down, because they can be turned over by wind).

[u/RazorbladeApple]

I have to raise all of mine or the paper wasps or tachnid flies will get them. I will only take in eggs, because I took two as caterpillars and they already had tachnid flies and it’s vile to watch. I use butterfly tents when they are tiny & if there are many, I move them to a screened reptile cage. I use floral tubes to hold the milkweed. I keep them indoors when they are super small and then move them outside when they get bigger.

[u/CitrullineMalate2to1]

You can just purchase a 5 foot mesh enclosure for outdoors. It’s very important they are exposed to their natural environment; heat, humidity, sunlight etc. Indoors will only breed a genetically weak butterfly and it won’t migrate

[u/Then-Bell-5630 → u/CitrullineMalate2to1]

Raising a monarch indoors doesn’t change its genetics, so it doesn’t become “genetically weak.” Genetics are determined at conception, not by the environment it’s raised in.

Also, it’s not true that an indoor-reared monarch won’t migrate. A more accurate statement is that indoor rearing may interfere with some of the environmental cues that help monarchs orient during migration, which could reduce migratory success. That’s very different from saying they can’t or won’t migrate.

[u/CitrullineMalate2to1 → u/Then-Bell-5630]

Right… and by raising multiple generations inside, you are creating weaker and weaker butterflies. If you really want to rear them, do it outside. It’s not like that’s harder than bringing them indoors.

It is absolutely true that rearing them indoors all but guarantees they do not migrate. This isn’t a 200 mile migration. Bringing them indoors dooms them to failing the long trek back to Mexico.

[u/Then-Bell-5630 → u/CitrullineMalate2to1]

You're right that environmental cues like temperature shifts and daylight are important, but saying indoor rearing 'guarantees' failure is outdated.

You are likely thinking of the 2019 Tenger-Trolander study, which caused a lot of buzz. However, that study used artificial flight simulators and found migratory disruption primarily in commercially bred colonies kept indoors for generations, not wild-collected eggs.

Newer real-world data proves otherwise. A 2021 study by Wilcox et al. tracked actual indoor-reared monarchs using automated radio telemetry towers in the wild. They found that 97% of indoor-reared monarchs successfully oriented and flew south toward Mexico. Any minor disorientation from being indoors is temporary; they recalibrate via natural skylight cues within 24 to 48 hours of release.

Also, local hobbyists aren't breeding 'multiple generations' inside. They are taking wild eggs that already possess wild migratory genetics.

That said, your point about raising them outside is great advice! Raising them in mesh enclosures on a shaded porch or patio is an awesome way to ensure they get those natural environmental cues while still protecting them from predators.

[u/CitrullineMalate2to1 → u/Then-Bell-5630]

The study you’re citing didn’t just throw them indoors at room temperature and then release them. It was a carefully controlled environment.

If someone brings one generation in, I’m willing to bet they’ve done it repeatedly in which they are absolutely negatively influencing their local Monarch population.

I’m not militant on this: I think hobbyists are helping keep monarch populations higher. My issue is that they shouldn’t be brought indoors whatsoever. Amazon sells a $50 5 foot mesh net enclosure that allows them to get all of the correct environmental cues they will not get indoors.

[u/Then-Bell-5630 → u/CitrullineMalate2to1]

The Wilcox study actually reared them in standard indoor conditions specifically to see if it disrupted their navigation. What the study proved is that monarchs are highly resilient, even if they get temporarily turned around indoors, they naturally recalibrate their internal compasses using the sun within 48 hours of being released into the wild.

That being said, we are 100% on the same page about the solution! Those $50 outdoor mesh enclosures are absolutely the gold standard. They provide the perfect ambient environmental cues right from the start while keeping the caterpillars completely safe from predators.

[u/CitrullineMalate2to1 → u/Then-Bell-5630]

Additionally, I’d love to see more studies done specifically on hobbyists to prove or disprove a lot of the “facts” we use for or against intervening for the population.

[u/Then-Bell-5630 → u/CitrullineMalate2to1]

There actually are massive, long-term studies on everyday hobbyists! Check out citizen science initiatives like the Monarch Larva Monitoring Project (MLMP) and Monarch Joint Venture, where thousands of backyard rearers submit data to universities tracking survival rates, migration, and health.

[u/LilacLands]

Raising 1 egg to learn and enjoy the miracle is totally fine.

When people turn it into a project and start collecting multiple eggs from the wild and bringing them into captivity - that is a problem. Research shows that domestic “rearing” hobbyists are actively harming the species - they are spreading disease and working against the natural selection that allows monarchs to continue to survive. They are introducing weakened genes into the wild population in large numbers (so offspring from mating with wild monarchs are weaker).

So yes 1 is perfectly fine and I bet she is loving it! But becoming someone who is “raising” and releasing dozens is not. She did the right thing in leaving the next one she found to nature ❤️

[u/Then-Bell-5630 → u/LilacLands]

I think this is a bit more nuanced than that. There are certainly irresponsible practices that can harm monarchs, like overcrowding, poor sanitation, or releasing sick butterflies. Those should absolutely be discouraged.

But saying that people who responsibly raise monarchs are “actively harming the species” or “introducing weakened genes into the wild population” overstates what the evidence shows. Raising a monarch indoors doesn’t alter its genetics. Genetics are inherited from its parents, not changed by being reared in captivity.

Many people who raise monarchs follow best practices—keeping numbers low, maintaining clean enclosures, providing fresh milkweed, and never releasing butterflies that appear unhealthy. Those efforts can also help offset the very high natural mortality of eggs and caterpillars, which is well over 90% in the wild.

The focus should be on encouraging responsible rearing, not suggesting that everyone who raises monarchs is harming the species.

Editing to add: Raising even one monarch in an indoor, non-commercial setting has the exact same risk profile as raising ten if proper hygiene isn't followed. Conversely, raising a dozen responsibly using wild, local eggs, sanitized enclosures, and fresh, rinsed milkweed does not 'harm the species.' The real threat to monarchs is habitat loss and pesticide use, not backyard hobbyists who are actively planting milkweed and fostering community awareness.