I am a strong believer in listening to people who know what they are talking about. Unfortunately, sometimes people who usually know what they are talking about shoot themselves in the foot, often by insisting that they know more than they really do.
An example is the current controversy over captive rearing of Monarch butterflies. This is an increasingly popular hobby for many gardeners and others who wish to help restore the population of this beautiful species. The rationale is that 90%+ of Monarch caterpillars do not survive to adulthood (due mainly to predators), but a large majority of those raised indoors do survive so that they can be released as mature butterflies.
Judy and I raised a few Monarchs indoors this year for the first time (fewer than 10), and I can attest that it’s exciting and fun.
But then along came the Xerces Society for Invertebrate Conservation, certainly a worthy organization. However, they published a blog post that was highly critical of captive rearing of Monarchs. This has caused a lot of people to become pretty upset.
Essentially, the post argued that captive rearing was counterproductive because:
- it allows less fit Monarch caterpillars to survive, thus weakening the Monarch gene pool;
- it could lead to a mismatch between the number of Monarchs and available resources (too many Monarchs, too little Milkweed);
- it promotes the spread of parasitic disease due to crowded conditions.
For more detail, go read the whole thing.
A response to the Xerces Society was posted by Chip Taylor, Director of Monarch Watch and Professor of insect ecology at the University of Kansas. Taylor is agnostic on the subject of captive rearing – neither for nor against. In fact, he considers the debate to be an unwelcome distraction.
Taylor argues that the number of captive reared Monarchs released is simply too small to have a significant impact, good or bad, on the overall Monarch population.
What’s more, he says, there is really no data that shows any impact, positive or negative, of releasing captive-reared Monarchs.
The Xerces Society did cite one study that seemed to show a lower survival rate for captive bred Monarchs as opposed to those bred in the wild. However, one of the authors of that study has written that the Society drew unwarranted inferences from his work.
In part, that’s because he was looking at captive bred Monarchs versus wild bred, but captive reared Monarchs are not captive bred. Rather, they are bred in the wild and then brought inside as eggs or caterpillars to be reared.
Beyond that, the issues raised by the Xerces Society are speculative. Certainly, Monarch caterpillars should not be raised in crowded conditions and enclosures need to be cleaned and sanitized – but this is something pointed out in every resource on rearing Monarchs that I have seen.
Taylor argues that habitat loss is the most urgent challenge for Monarch conservation. He cites estimates that one billion additional stalks of Milkweed, mostly in the Upper Midwest, are needed to build a sustainable Monarch population. To read all of Taylor’s post (via Kylee Baumlee’s blog, Our Little Acre), click here.
So apparently, gardeners raising Monarchs at home will not boost the Monarch population in any meaningful way. But there’s no reason to think that it does any harm.
Perhaps the greatest value of rearing Monarchs is not its impact on the butterfly, but its affect on people. Based on our own experience and that of friends, I would say that rearing Monarchs unquestionably creates more Monarch enthusiasts. For Judy and I, it was almost a bonding experience with the species.
More Monarch enthusiasts, I think, means more people willing to dig up more of their lawn and plant more Milkweed and other butterfly-friendly plants. It means more people who will support projects and policies that contribute to Monarch conservation. And that is certainly a positive thing.
I have been a Monarch Waystation as part of Monarch Watch for a number of years. I have several kinds of milkweed, and keep adding more. When the kids were young, we raised a few swallowtails inside a season or two, but I have never raised monarchs, and do not desire to. I am glad Chip has kept that neutral. I love seeing butterflies of many kinds on the various blooms in the yard, and that is my contribution for their livelihood. I am sorry that that offends some people who go out and look for eggs to raise inside.
Hi Sue. I don’t think that anyone is offended by someone NOT rearing Monarchs inside. What you’ve done with your garden is exactly what people need to do. The debate is whether raising Monarchs indoors is helpful or not. I thought it goes without saying that gardeners should do what they can to mitigate the loss of natural habitat.
Interesting debate–enjoyed reading different views. Mostly, glad to hear about people trying to help butterflies.
So am I.
It is common sense that these butterflies need all the help they can get. And what fun it must be.
It certainly is!
Education!!! I for one, have learned from watching 4 of the caterpillars I was rearing, die a slow and apparently agonizing death, after ingesting some tainted (chemicals) milkweed that a friend gave me
to not trust the chemical companies claim that their chemicals are “safe”. Even spraying just the lawn can create some over spray and get on the milkweed!
Yeah, it drives me crazy when the neighbors allow landscapers to spray their property. Fortunately it happens rarely.
As I have said before I can’t imagine that it would be detrimental to the species. Like they do birds and many mammals etc. Raising them and releasing them into the wild to keep populations from becoming extinct. It works or at least helps populations. Keep planting that milkweed.
Milkweed, yes – and don’t forget the nectar plants!
Good post. I think Taylor’s position makes sense as a (former) population biologist. It’s a small percentage of the total population. Thanks for the links-i had meant to read Kylee’s post earlier.
It’s hard to evaluate these competing claims as someone with no training in the field. But it does seem to me that the Xerces folks were offering very little in the way of solid evidence.
I raised a couple of black swallowtail caterpillars as a little girl. It’s something I’ll never forget!
It’s magical, isn’t it?
This is almost as heated as a political debate. Interesting. When my grandkids were young, we raised some and it was magical. We’re also a Monarch way station, and I go out of my way to plant things that they need and enjoy. I do not in my wildest imagination see how raising a few Monarchs while dedicating your garden to their survival could be remotely negative. Garden on.
That’s how I see it.
Interesting article Jason and Judy. I have participated in a butterfly release, but never raised them. I watched many in the caterpillar stage disappear from my parsley and dill (swallowtails) and was disappointed they didn’t mature. Any help these beautiful winged creatures can get is well worth it.
I’ve had the same experience of going back to find caterpillars only to see that they are gone.
I have a friend who raised three monarch caterpillars indoors this year. She said that, apart from cleaning the cage of frass twice a day as they grew larger, it was a most exciting experience to watch them become chysalides and then emerge as beautiful butterflies to be released. Three for three and she has the pictures to show it! Those eggs were laid and caterpillars reared on tropical milkweed. Another subject for debate, I hear!
(I had avoided planting common milkweed until this summer because of its aggressive nature, but I’ve succumbed!)
I do stay away from the Tropical Milkweed, just to be on the safe side. Plus, there’s lots of native Milkweeds to choose from!
I have a lot of milkweed in my garden and was watching the progress of a monarch caterpillar a week or so ago. I couldn’t find it one afternoon and hunted around the plant. I found it on the ground being devoured by two wasps. I could kick myself for not bringing it inside to a safe place. I won’t make the same mistake again.
I’ve had similar experiences.
Great post, Jason and Judy. For various reasons, I’ve been holding back on writing about this issue myself, but will be sure to link to this post once I do.
Thanks, Helen. I’ll be interested to see your thoughts.
I agree with Chip Taylor.
He seems to make a stronger case, doesn’t he?
Good points, and getting people to love and appreciate monarchs can be nothing but good.
That’s what I think.
This is very good, Jason. You are so wise and well-spoken. Yes! Plant more Milkweed and nectar plants! If everyone did that, it would help the species immensely and the debate about captive-raising would be a non-issue.
That seems to be what we should be focusing on.
Yes, more monarch enthusiasts is a good thing. Unfortunately, milkweed doesn’t occur naturally in these parts so no monarchs.
That is unfortunate. But still, nature is generous in your part of the country.
hmmmm. I must agree that there are not enough of the released butterflied to be a detriment to the rest of the population. There are so many out there! (I went to school in San Luis Obispo, so am familiar with the swarming monarch butterflies in Monarch Grove in Los Osos. I am still none too keen on this butterfly fad though. The swarming butterflies in the red and blue gums are not out where they belong, pollinating native plants that depend on them for pollination. Planting more plants that butterflies like in home gardens is nice for attracting monarch butterflies to home gardens, but is not an advantage for the native specie that depend on the butterflies that are going to home gardens instead.
That is an interesting point. Like you, I don’t really like this Monarch mania. I was monitoring over 40 species of butterfly at Illinois Beach State Park for over 10 years. They are ALL struggling, and it feels to me that even people I would expect would know better only seem to care about Monarchs.
When the SODS (Sudden Oak Death Syndrome) started to kill the tan oaks, it did not get much attention. Most of us who are familiar with tan oaks are none to keen on them. When it started to kill the stately coast live oaks, we really took notice! It was too late of course. (It could not have been stopped even if we knew about it earlier.) There are so many different plant diseases showing up in Los Angeles now, and even those who are concerned can not keep up with it all!
That is a worrying one. An initiative here has begun of actually thinning our beloved bur oaks. The thought being that if we create gaps, the disease cannot be passed through the roots. I have reservations about it. A problem we face here in Illinois is that the oaks don’t seem to regenerate very often. We have stands of oaks throughout the county that are all of an age, and beginning to die off, with no babies at their feet.
Is SODS a problem there?! I have not been monitoring it outside of our region.
I have not been as involved as I once was, so I’m not sure whether it has arrived here. I do know that the ecologists were gravely concerned because oaks are extremely important in our woodlands.
A year or two ago we lost all of our green ashes to emerald ash borer. No great loss as far as specific trees go, but it was amazing to watch a significant portion of our canopy die. I’ve allowed a baby ash, a daughter of my neighbor’s tree, to grow. I’m curious whether the beetles are still in the area and whether they will find my little tree. What is happening to your oaks is dreadful.
It put us out of business for more than a year, as our material was quarantined. Even though it came to our region last, we were blamed for spreading the disease.
These sorts of things are never fair. I’m so sorry to hear that. Not many companies could come back from that!
Because the town has expanded around the farm, the land is extremely valuable. Developers have been wanting it for decades. We are often blamed for contaminants in the Creek, but they are contaminants that we do not generate. Developers pay inspectors to find problems. I do not doubt that they payed some of those researching the SODS to blame us for the dispersion of the disease.
It would never occur to me that that sort of thing went on! How terrible.
It is common here because the property is some of the most expensive in America. Greed makes people do some weird things. Gentrification does not help much either. The Santa Clara Valley used to be famously agricultural.
My grandparents bought their home in Eureka back in the late 50’s, I believe. I’ve often wished I could have bought early there because I sure can’t afford to move back now. But from what you describe, I guess I wouldn’t enjoy the pressures of those who’d want to obtain my property. sad. I’ve probably already told you what became of my grandparents house~it was a classic case of cutting down the trees and putting up a parking lot, complete with klieg lights. My mother sold out and I don’t blame her.
Well, California is a big place. Eureka is far away from here, and is still a very nice place. There are still many nice places. The San Francisco Bay Area just is not as nice as other places. I sometimes tell my friends here that this is NOT a place that I would move to if it were not my home.
It used to be. Clearly a case of being loved to death. 😦
“Perhaps the greatest value of rearing Monarchs is not its impact on the butterfly, but its affect on people.” Jason, I think you nailed it! I also don’t think many would raise the butterflies, and not simultaneously grow the Milkweed they need, so I don’t quite understand the Xerxes assertion in that regard. Great post!
Thanks. I think the Xerxes folks were dealing with hypotheticals, they didn’t really have any evidence, at least not on that point.
I love that there are so many people out there who would care enough to have this debate.
That is an encouraging thought.
I took a look at your website – very nice! I left a comment but it may have gone to your spam folder.
The best use of rearing Monarchs at home is as a teaching tool, but I agree with Chip Taylor that’s it’s a bit of a distraction. Great post, Jason and lovely photos. I’m eagerly awaiting Monarchs through my garden as they head to Mexico.
Every time I see a Monarch these days I’m surprised. I want to ask it if it isn’t behind schedule on its trip south.
Lovely post. There’s a lifelong positive effect on kids if they rear ANY caterpillar into moths or butterflies, in my opinion. I can still remember the sheer magic of having Luna moths in the classroom when I was about 6 years old. And they laid eggs on my pencil as well!
Oh no, I suppose you could never use that pencil again.
I think your assessment is right, the more people who think about providing plants for the caterpillars as well as nectar flowers the better and that comes from feeling responsible; there’s nothing like watching something hatching to give you that feeling.
It creates an emotional connection that is more powerful than an intellectual understanding.
I raised a half-dozen or so, and found it very educational (and I’m 65+ years old!) Now I know what the eggs look like and how to find them, the stages of larva development, what the chrysalis looks like when the butterfly is about to emerge and what it looks like after, and how sticky butterfly feet feel on my finger. And it was fun!
It certainly is fun, and educational!
I agree, but it is going to take more than planting milkweed. ALL of our butterfly species are in decline. I suspect it has a lot to do with the chemical sprays and GM corn wafting its Bt pollen about, because even in preserves where once there were many insects of all varieties, now there are very few. The more enthusiasts, and the more informed they are, the better.
It’s a grim situation, but nothing is gained by giving up.
Oh I’m not giving up. I just want people to understand this involves more than just monarchs, and the solution will take more than only planting milkweeds. I guess I worry because the situation is being presented so simplistically.
Not sure how much complexity most people are able to absorb. Depends on the audience, I guess.
Well, you’re probably right about that and every little bit helps. I hope that people also hear that chemicals are killing our insects, so they’ll stop and think a little before happily spraying away.