What to do about the decline of the monarchs? The recent Thanksgiving count in California was dire. The spiral in eastern north America is no better. The monarchs need many things, and milkweed is absolutely essential. It is the only plant their caterpillars eat. And as described in my book, Monarchs and Milkweed, the two share an intimate and antagonistic evolutionary history. While monarchs continually evolve to keep up with milkweed, milkweed too constantly evolves better and better defenses. But, in Europe, where the common milkweed (Asclepias syriaca) was introduced over 400 years ago, there are no monarchs. What follows below is part travel log, part natural history diary, and part historical journey regarding milkweeds and their bugs in Europe. At the bottom, I end with a modest proposal for what we might do. Here we go.
The genus Asclepiashas about 140 species (in the botanical family Apocynaceae), with >90% from temperate North America, and the lion’s share of them in Mexico and the SW USA. Click here for a visual smattering of milkweed floral diversity. Only a handful are tropical, from Central America and northern S. America. Although sometimes controversial, the sister to Asclepias,Gomphocarpus is a genus of >200 old-world species, all in Africa. But, Asclepias does have a history in Europe, an unnatural history that starts >400 years ago. But I am getting ahead of myself. My exploration of Asclepias in Europe started with research for Monarchs and Milkweed, continued with a research project on evolution of introduced milkweed in Europe, and most recently culminated with a trip to Hungary. Let me start with the last first.
20 Replies to “Milkweeds but not monarchs in Europe: natural and cultural history (and a modest proposal)”
When I was doing research for my own book, I came upon milkweed honey. Of course, I had to have it, but it was nowhere to be found, commercially anyway. It seemed only to be produced in Hungary, where as you know, Asclepias isn’t native, but grows very well in certain areas. To make a long story short, a friend of a friend of a friend just happened to be a milkweed honey producer in Hungary. They can only sell it to members of the EU, but friends can do remarkable things. The path two pints of milkweed honey took was Hungary>England>Texas>Ohio. I got my honey, and yes, it’s everything it’s lauded to be.
It seems a bit strange to say that there are no monarchs in Europe, but there is an established population in Spain, which is, I think, generally considered to be a European country. However, from the map, I see your point. Monarchs are not able to cross the Pyrenees.
Do you suppose this is simply a difficulty caused by altitude? Or a problem due to a lack of some resource in the mountains?
The map suggests a similar situation in the US, with the California population isolated by the Rocky Mountains. Could it be the same problem?
As for the signs in Hungarian, Google Translate says the sign with the gun image has the text “Armed Area”, which I suppose means “There be guns here.” The sign above it says “Protection area for drinking water”.
Tim, I cannot believe you actually read this thing! Thank you. Of course Spain is in Europe, but more remarkable is your insight! Especially in Europe, there are probably no milkweeds in the mountains, whereas feral milkweeds abound in the southern lowlands. There very well be some climate stuff going on as well. I think in the Rockies there is milkweed to 7000 or so feet, but not above.
And thanks for the translate… A friend from Toronto, Don Davis, wrote this: So happens my nephew’s wife is from Hungary. So….the signs you photographed and posted in your blog reads: “City water works protected property, Potable water wells protected area, Property guarded by armed security”
“Property guarded by armed security” makes more sense than “Armed area”, but Google Translate did okay, I think, with the other sign.
As for the mountain barrier, it makes sense that the monarch would not expand its range incrementally across a region without milkweed.
It still puzzles me that individual monarch females haven’t accidentally crossed the range, either carried on storm fronts, or driven by zugunruhe, frequently enough to establish a permanent population north of the Pyrenees, as they have on the other side of the Rockies. Apparently this happens occasionally, but not sufficiently. There must be some reason beyond the absence of milkweed in the mountains that prevents the establishment of a population in southern France.
The probability of a successful establishment must be much lower than I think. The difficulty of establishing permanent populations of biocontrol agents suggests that I am too optimistic. The minimum ecosystem requirements for most species are probably more complicated than we imagine, that is, species are embedded in their habitat more precisely than we suppose (a major theme in Kim Stanley Robinson’s SciFi novel “Aurora”).
I can’t find any counts earlier than 1997 your buddy must have them hidden so we have to buy his story. There’s only 2 things weather or predators so what is it ?? Cooper over in New Zealand says the paper wasp is killing all the monarchs and the population is in the sewer. https://xerces.org/monarchs-old/western-monarch-thanksgiving-count-graph/
Anurag, I’m reading your blog!
😍
“we should take their [monarchs] decline as a wake up call, not as a call to arms to fix this one small problem.”
The eastern USA monarch overwintering population has actually been stable for the past 8 years: http://imagizer.imageshack.us/a/img923/3720/nb8gWN.jpg And the fall migration of 2018 was spectacular at times in the Midwest USA like this: Video shot at sunset as the butterflies were coming down from high altitude migration: https://youtu.be/aDovxuP_WUc
Until 2018 the California overwintering population had been stable for about 17 years: http://imagizer.imageshack.us/a/img922/2313/l9yaVv.jpg Although 2018 has turned out to be anomalously record low year in California, the western USA population has reliably recovered from deep lows in the past.
Just like Earth’s climate. Completely stable. I guess all the talk about Mexico developing land the monarchs hibernate in was much ado about nothing, too.
The only stability I see is the encroachment of the burgeoning human population and its rapacious ever-growing appetite for per-capita consumption.
That is the one thing one can count upon: Greedy ignorance.
Both of your data charts showcase precipitous drops. Stability whilst circling the drain is cold comfort.
Of course weather patterns, mostly catastrophic drought determine wildlife populations although the native plants that go dormant have to recover or very much life on the planet never would have existed. We know by fellow Austini, Bill Calvets studies of fireants in the 90s spreading across the south what a detriment fireants are to wildlife including monarchs. Since most milkweed and common specifically is actually invasive and spreads on it’s own during times of normal participation many times more milkweed stems exist now than even before GMO. This , of course is because more people are letting it exist in non cropland areas especially in the summer breeding grounds. Increase predation is most likely the hard to study culprit in holding monarch populations down but that won’t stop the tax dollar and grant seekers from continuing to promote planting invasive weeds. Have some fun and raise some monarchs. At least you can feel like your making some kind of legitimate contribution even if monarchs and other butterflies disappear completely
Everything I have read from legitimate sources has shown that milkweed populations in North America have shrunk. This isn’t just because of the relentless onslaught of “development” but also because of Roundup and the fact that American farmers, at least all of those in my area (Indiana and Ohio) are clueless about beneficial ecological practices like beetle banks. All the university “extension” pages are all about which chemical to dump on the land to solve every problem and every plant that’s not agricultural or merely decorative is a weed that establishes “infestations”. Is it surprising that practically every forb in the US that isn’t from Europe has “weed” in its name?
Not only are there fewer milkweeds, the populations are more fragmented. Some are on the verge of extinction. Mead’s milkweed, which the government has been trying to reestablish, exists with only 11-12% of its plants on protected land and politicians these days are moving toward privatizing/exploiting protected lands. Most of the plants are mowed so they can’t go to seed. Some populations are so genetically non-diverse that they have difficulty producing viable seed. Some Mexican species are barely documented. For example, good luck finding a source for melantha seed, or Mead’s, or many other Asclepias species.
I also find your post a bit baffling because you seem to be claiming that A) there are more milkweed plants now than there have been before and B) there isn’t much point in trying to help the monarch because it’s likely to become extinct.
It is likely to become extinct, becoming added to the very long and ever-lengthening list of our species’ slaughter — “for jobs and profit”. That list will eventually have our name added to it. Yes, I am extremely pessimistic (aka realistic) but I also plant milkweeds and support the idea of establishing biological control populations. Fiddling while Rome burns is lazy and a bit dull. If we fight the law (the law = money talks) the law will win. But, it’s better to keep busy than to throw in the towel.
Syrica milkweed is not invasive. Corn is invasive. Soybeans are invasive. Humans are invasive. Syrica milkweed is eaten, simultaneously, by so many insects that it’s a wonder it manages to survive at all. No plant in my area is more of an insect haven.
Nice to meet you Charles. If you Google “Craig the Butterflyman” you can find out a little more about how I contribute and if you like you can join my 2000+ member Public Facebook group “How to Raise Monarch Butterflies” and learn what the people I teach are doing to actually add to the monarch butterfly population instead of “wondering”. Or like most scientists prefacing all their comments with “could” or “maybe” Yes, what I teach Is ecologically correct and approved by many biologists and butterfly experts including U S Fish and Wildlife biologists and once multiplied and released they feed the entire wildlife food chain through breeding in the wild.
Love your book. Here’s an oddball question for you—do monarch eggs contain any cardiac glycosides? Or, does ingestion begin with the caterpillar and end with the adult butterfly? Thank you!
Thank you! There are very low levels of cardiac glycosides in eggs, but to my *opinion* probably not enough to be ecologically important. Of course I could be wrong!
I am a casual reader who just happened upon your post while looking into Monarch butterfly disappearance.
Thanks for the informative documentation.
I think that all efforts to protect and save species from extinction help to awaken communities’ commitment to saving our planet from our own destructive habits.
Your post inspires me to add milkweed to my list of native species to plant here in Ohio.
We are being overwhelmed by garlic mustard and tree of heaven.
My hope is to form a local group committed to irradicating these species locally and to plant native species in our parks and in the fragmented forested areas left as public lands.
Our group could also work to inspire the public here to tend to their own lands in this way; to understand their wild lands as gardens.
I was able to document the intrusion of garlic mustard into our small nature preserve via the cell phone tower access road that was built. I have also found that off-roading destroys the fungal network of the forest system.
I was told so many times that we cannot stop the spread of the invasive species mustard garlic. But I have successfully learned how to pull it with its roots. Repeated seasonal effort results in the irradication of this plant and its toxic root system.
The effort is easiest and most efficient if one pulls the plants out from the base after some days of rain, throughout its growing season into June. To avoid spreading the seeds do so before the seeds are released or at the end of their growing season. I set a single local pile on a tarp; roll it and transport it without releasing the seeds.
Maybe one day we will have a National Invasive Species Irradication Month! Heck, I’ll settle for a National Invasive Species Irradication Day.
Our public areas are the safest transportation hubs for all migrating species. We should tend to these areas just as we would a garden and try to expand every fragment of wild space that is left.
Very interesting blog: though not an expert in anyway, I love to read about the Monarch Butterfly. My reason to comment is to bring to your attention the presence of the Monarch Butterfly around the British Overseas Territory of Gibraltar, another European country. Their presence is seen in many parts of Gibraltar, especially by the Trafalgar Cemetery and the Alameda Botanical Gardens.
I remember when at Middle School in Gibraltar we would breed Monarchs and Great Admirals in netted tents and then set them free. This was for the metamorphosis course. Around 30 years ago,still see an immense population around.
When I was doing research for my own book, I came upon milkweed honey. Of course, I had to have it, but it was nowhere to be found, commercially anyway. It seemed only to be produced in Hungary, where as you know, Asclepias isn’t native, but grows very well in certain areas. To make a long story short, a friend of a friend of a friend just happened to be a milkweed honey producer in Hungary. They can only sell it to members of the EU, but friends can do remarkable things. The path two pints of milkweed honey took was Hungary>England>Texas>Ohio. I got my honey, and yes, it’s everything it’s lauded to be.
It seems a bit strange to say that there are no monarchs in Europe, but there is an established population in Spain, which is, I think, generally considered to be a European country. However, from the map, I see your point. Monarchs are not able to cross the Pyrenees.
Do you suppose this is simply a difficulty caused by altitude? Or a problem due to a lack of some resource in the mountains?
The map suggests a similar situation in the US, with the California population isolated by the Rocky Mountains. Could it be the same problem?
As for the signs in Hungarian, Google Translate says the sign with the gun image has the text “Armed Area”, which I suppose means “There be guns here.” The sign above it says “Protection area for drinking water”.
Tim, I cannot believe you actually read this thing! Thank you. Of course Spain is in Europe, but more remarkable is your insight! Especially in Europe, there are probably no milkweeds in the mountains, whereas feral milkweeds abound in the southern lowlands. There very well be some climate stuff going on as well. I think in the Rockies there is milkweed to 7000 or so feet, but not above.
And thanks for the translate… A friend from Toronto, Don Davis, wrote this: So happens my nephew’s wife is from Hungary. So….the signs you photographed and posted in your blog reads: “City water works protected property, Potable water wells protected area, Property guarded by armed security”
“Property guarded by armed security” makes more sense than “Armed area”, but Google Translate did okay, I think, with the other sign.
As for the mountain barrier, it makes sense that the monarch would not expand its range incrementally across a region without milkweed.
It still puzzles me that individual monarch females haven’t accidentally crossed the range, either carried on storm fronts, or driven by zugunruhe, frequently enough to establish a permanent population north of the Pyrenees, as they have on the other side of the Rockies. Apparently this happens occasionally, but not sufficiently. There must be some reason beyond the absence of milkweed in the mountains that prevents the establishment of a population in southern France.
The probability of a successful establishment must be much lower than I think. The difficulty of establishing permanent populations of biocontrol agents suggests that I am too optimistic. The minimum ecosystem requirements for most species are probably more complicated than we imagine, that is, species are embedded in their habitat more precisely than we suppose (a major theme in Kim Stanley Robinson’s SciFi novel “Aurora”).
When California droughts subside California’s monarchs will recover some
just like happened after the droughts on the eastern range. https://en.m.wikipedia.org/wiki/2011%E2%80%932017_California_drought
Monarchs numbers in California boomed during the 2012-2016 and 1988-1991 droughts: https://youtu.be/hJKNOHSNQg8
I can’t find any counts earlier than 1997 your buddy must have them hidden so we have to buy his story. There’s only 2 things weather or predators so what is it ?? Cooper over in New Zealand says the paper wasp is killing all the monarchs and the population is in the sewer. https://xerces.org/monarchs-old/western-monarch-thanksgiving-count-graph/
Anurag, I’m reading your blog!
😍
“we should take their [monarchs] decline as a wake up call, not as a call to arms to fix this one small problem.”
Amen
The eastern USA monarch overwintering population has actually been stable for the past 8 years: http://imagizer.imageshack.us/a/img923/3720/nb8gWN.jpg And the fall migration of 2018 was spectacular at times in the Midwest USA like this: Video shot at sunset as the butterflies were coming down from high altitude migration: https://youtu.be/aDovxuP_WUc
Until 2018 the California overwintering population had been stable for about 17 years: http://imagizer.imageshack.us/a/img922/2313/l9yaVv.jpg Although 2018 has turned out to be anomalously record low year in California, the western USA population has reliably recovered from deep lows in the past.
Just like Earth’s climate. Completely stable. I guess all the talk about Mexico developing land the monarchs hibernate in was much ado about nothing, too.
The only stability I see is the encroachment of the burgeoning human population and its rapacious ever-growing appetite for per-capita consumption.
That is the one thing one can count upon: Greedy ignorance.
Both of your data charts showcase precipitous drops. Stability whilst circling the drain is cold comfort.
Of course weather patterns, mostly catastrophic drought determine wildlife populations although the native plants that go dormant have to recover or very much life on the planet never would have existed. We know by fellow Austini, Bill Calvets studies of fireants in the 90s spreading across the south what a detriment fireants are to wildlife including monarchs. Since most milkweed and common specifically is actually invasive and spreads on it’s own during times of normal participation many times more milkweed stems exist now than even before GMO. This , of course is because more people are letting it exist in non cropland areas especially in the summer breeding grounds. Increase predation is most likely the hard to study culprit in holding monarch populations down but that won’t stop the tax dollar and grant seekers from continuing to promote planting invasive weeds. Have some fun and raise some monarchs. At least you can feel like your making some kind of legitimate contribution even if monarchs and other butterflies disappear completely
Everything I have read from legitimate sources has shown that milkweed populations in North America have shrunk. This isn’t just because of the relentless onslaught of “development” but also because of Roundup and the fact that American farmers, at least all of those in my area (Indiana and Ohio) are clueless about beneficial ecological practices like beetle banks. All the university “extension” pages are all about which chemical to dump on the land to solve every problem and every plant that’s not agricultural or merely decorative is a weed that establishes “infestations”. Is it surprising that practically every forb in the US that isn’t from Europe has “weed” in its name?
Not only are there fewer milkweeds, the populations are more fragmented. Some are on the verge of extinction. Mead’s milkweed, which the government has been trying to reestablish, exists with only 11-12% of its plants on protected land and politicians these days are moving toward privatizing/exploiting protected lands. Most of the plants are mowed so they can’t go to seed. Some populations are so genetically non-diverse that they have difficulty producing viable seed. Some Mexican species are barely documented. For example, good luck finding a source for melantha seed, or Mead’s, or many other Asclepias species.
I also find your post a bit baffling because you seem to be claiming that A) there are more milkweed plants now than there have been before and B) there isn’t much point in trying to help the monarch because it’s likely to become extinct.
It is likely to become extinct, becoming added to the very long and ever-lengthening list of our species’ slaughter — “for jobs and profit”. That list will eventually have our name added to it. Yes, I am extremely pessimistic (aka realistic) but I also plant milkweeds and support the idea of establishing biological control populations. Fiddling while Rome burns is lazy and a bit dull. If we fight the law (the law = money talks) the law will win. But, it’s better to keep busy than to throw in the towel.
Syrica milkweed is not invasive. Corn is invasive. Soybeans are invasive. Humans are invasive. Syrica milkweed is eaten, simultaneously, by so many insects that it’s a wonder it manages to survive at all. No plant in my area is more of an insect haven.
Nice to meet you Charles. If you Google “Craig the Butterflyman” you can find out a little more about how I contribute and if you like you can join my 2000+ member Public Facebook group “How to Raise Monarch Butterflies” and learn what the people I teach are doing to actually add to the monarch butterfly population instead of “wondering”. Or like most scientists prefacing all their comments with “could” or “maybe” Yes, what I teach Is ecologically correct and approved by many biologists and butterfly experts including U S Fish and Wildlife biologists and once multiplied and released they feed the entire wildlife food chain through breeding in the wild.
Love your book. Here’s an oddball question for you—do monarch eggs contain any cardiac glycosides? Or, does ingestion begin with the caterpillar and end with the adult butterfly? Thank you!
Thank you! There are very low levels of cardiac glycosides in eggs, but to my *opinion* probably not enough to be ecologically important. Of course I could be wrong!
I am a casual reader who just happened upon your post while looking into Monarch butterfly disappearance.
Thanks for the informative documentation.
I think that all efforts to protect and save species from extinction help to awaken communities’ commitment to saving our planet from our own destructive habits.
Your post inspires me to add milkweed to my list of native species to plant here in Ohio.
We are being overwhelmed by garlic mustard and tree of heaven.
My hope is to form a local group committed to irradicating these species locally and to plant native species in our parks and in the fragmented forested areas left as public lands.
Our group could also work to inspire the public here to tend to their own lands in this way; to understand their wild lands as gardens.
I was able to document the intrusion of garlic mustard into our small nature preserve via the cell phone tower access road that was built. I have also found that off-roading destroys the fungal network of the forest system.
I was told so many times that we cannot stop the spread of the invasive species mustard garlic. But I have successfully learned how to pull it with its roots. Repeated seasonal effort results in the irradication of this plant and its toxic root system.
The effort is easiest and most efficient if one pulls the plants out from the base after some days of rain, throughout its growing season into June. To avoid spreading the seeds do so before the seeds are released or at the end of their growing season. I set a single local pile on a tarp; roll it and transport it without releasing the seeds.
Maybe one day we will have a National Invasive Species Irradication Month! Heck, I’ll settle for a National Invasive Species Irradication Day.
Our public areas are the safest transportation hubs for all migrating species. We should tend to these areas just as we would a garden and try to expand every fragment of wild space that is left.
Very interesting blog: though not an expert in anyway, I love to read about the Monarch Butterfly. My reason to comment is to bring to your attention the presence of the Monarch Butterfly around the British Overseas Territory of Gibraltar, another European country. Their presence is seen in many parts of Gibraltar, especially by the Trafalgar Cemetery and the Alameda Botanical Gardens.
Thanks!
I remember when at Middle School in Gibraltar we would breed Monarchs and Great Admirals in netted tents and then set them free. This was for the metamorphosis course. Around 30 years ago,still see an immense population around.
I’m in Crete at 900 ft elevation. I have many butterflies in my garden and some look like monarchs.