A new study finds that monarch wings are getting larger, possibly because climate change has forced the butterflies to travel longer distances as breeding grounds shift farther north.
It’s not too late to save them, but it’s a question of whether we make the effort, scientists say.
6 Minute Read
PUBLISHED December 21, 2018
The epic 3,000-mile monarch butterfly migration may become a thing of the past. Each fall, monarchs travel from their summer homes in the northern U.S. and Canada to winter habitats in California and Mexico. But the 2018 Western Monarch Thanksgiving Count found that the number of west-coast monarchs spending the winter in California had plunged to only 20,456 butterflies—a drop of 86 percent since last year. And the number of eastern monarchs overwintering in Mexico this year has dropped 15 percent since last year, for a total decline of more than 80 percent over the past 20 years, according to the National Wildlife Federation.
“A lot of environmental threats can pile up on top of each other,” says University of Wisconsin entomologist and director of the UW-Arboretum Karen Oberhauser. And the consequences can be hard to predict.
Although monarchs teeter on the edge of an extinction tipping point—in which their numbers drop too low for the species to recover—scientists like Obserhauser say all is not yet lost. Creating new monarch habitat by planting native milkweed species may provide crucial fuel and rest stops for the traveling butterflies, as will taking more action to address climate change.
WHERE’S THE MILKWEED?
A 2004 email from a Midwestern farmer first alerted Kansas University entomologist Chip Taylor to the pending monarch apocalypse. The creation of herbicide-resistant corn and soybeans meant that farmers could eradicate weeds and other understory plants, including milkweed, that competed with their crops.
The invisible hand of fear and dread gripped Taylor’s gut. He had spent years studying monarchs and knew they depended on the milkweed studding their migratory corridor across the Midwest. The advent of these new crop varieties meant the death of milkweed.
Data over the next few years only confirmed Taylor’s worst fears: monarch numbers began to plummet. “In a very short period of time, monarchs took a tremendous hit, with tremendous consequences,” Taylor says.
In addition to the loss of milkweed across farms, drought also harms milkweed quality. A 2013 drought in Texas decimated milkweed there, which contributed to low monarch numbers that year.Nectar-rich flowers are important for monarchs’ continued survival. And milkweed, the only plant monarch caterpillars eat, is especially important.The loss of milkweed has clued in an increasingly concerned public that the beautiful butterflies they love might go the way of the passenger pigeon and the woolly mammoth. Awareness of vanishing milkweed bled over into fears of how monarchs would fare as the climate continued to change. A series of papers in the last few years shows that these worries were not misplaced.
Rising carbon dioxide levels from the burning of fossil fuels sit at the heart of climate change, and this increase of carbon can alter how plants like milkweed build certain molecules, explains ecologist Leslie Decker, a postdoctoral researcher at Stanford University. Milkweed produces toxic steroids called cardenolides. The monarchs have evolved in a way that allows them to tolerate low levels of this poison, storing it in their bodies as a bitter-tasting deterrent to predators.
Models predict an 11 to 57 percent chance that monarch numbers would drop so much in the next 20 years that the species wouldn’t be able to recover.
Cardenolides also help the butterflies by impeding the growth of a monarch parasite with the tongue-twisting name Ophryocystis elektroscirrha. “I had to practice pronouncing this when I was in grad school,” Decker laughs.
The single-celled parasite can infect newly hatched caterpillars by drilling holes in their gut to replicate. If the caterpillars survive, the resulting butterflies have misshapen wings and lowered endurance. Cardenolides help the monarchs tolerate the parasite so that it doesn’t harm them.
But when Decker grew milkweed in a greenhouse with carbon dioxide levels of 760 parts per million (ppm)—what climate scientists project will happen in 150 to 200 years as the current level of 410 ppm continues to rise—she found that the plants produced a different mix of cardenolides, one that was less effective against monarch parasites. She published her findings in July 2018 in Ecology Letters.
“We don’t know how we’re changing the green pharmacy around us,” Decker says.
Read the full story here
HT/RobD
” a monarch parasite with the tongue-twisting name Ophryocystis elektroscirrha. ”
…..and in a related paper
Ophryocystis elektroscirrha fails to thrive at CO2 450ppm…
…film at 11
Losing monarchs eh? Well that’s just careless. Heads of state should be better protected.
Australia managed to lose a prime minister once too, or was very embarrassing.
Growing up in Houston in the 80s and 90s, there were TONS of Monarchs every year. I’ve been back in Houston for 6 years and I don’t think I’ve seen one the entire time
“The monarch is the only butterfly known to make a two-way migration as birds do. …
Monarchs use a combination of air currents and thermals to travel long distances. Some fly as far as 3,000 miles to reach their winter home!”
Unless the air currents, at the time of migration always flow in the required direction, question is how they find their way there and back?
It is thought that some of migrating birds as well as homing pigeons may be using the earth’s magnetic field for navigation, so it may not be in the realm of a total fantasy to assume that the monarchs may have similar ability, which could be impaired by rapid changes in the intensity of magnetic filed.
This map
shows monarchs migration routes, while in this Link it can be seen the rapid acceleration (starting in the 1980s) in decline of the magnetic field intensity over the mid-west USA.
At this rate of the decline by 2050s the USA over-flying satellites will be exposed to dangerous levels of radiation (similar to the current South Atlantic anomaly area) having debilitating consequences for weather monitoring, hurricane tracking and the GPS navigation.
Link showing the rapid acceleration in decline of the magnetic field intensity over the mid-west USA:
http://www.vukcevic.co.uk/USA-MF.htm
This magnetic reversal happens about every 200K years or so.
We’re about due. It’s hard to judge because the cycle is pretty irregular. It’s also hard to judge because we aren’t sure how often the field collapses but reforms with the same orientation. The proxies we have only indicate the times it reforms reversed.
~¿~
The Earth’s MF field didn’t collapse during past reversals, magnetic poles just drifted across the equator on the, more or less, opposite sides of the globe.
If it did collapse the large proportion of the earth’s atmosphere would have been blown away by the solar wind during many reversals, and the most of the living organisms would have been killed off by the intense radiation.
Interesting. Where did you find that? What I remember reading was that the Earth’s magnetic field was supposed to break apart, possibly into as many as 6 much weaker dipoles, that wandered about independently until they reformed into a single dipole congruent to the pole of rotation. This new dipole could be orientated the same as the old one, or reversed.
~¿~
Alcohol based fuels are the problem-so to grow corn, you eliminate milkweed. The ethanol is used to reduce global temperature change? In doing so, you elimate Monarchs.
see! climate change IS the cause of the decline!
sort of..
We’re losing sitting ducks fast Blame on them. They just sit, don’t fly away, just wait to be fed.
Why didn’t Darwin do his studies in a continent instead of a small island?
I struggle to see the survival benefit of flying 4000 miles north and back every year. It actually takes several generations to make the trip.
Good question, maybe the struggle itself strengthens the species ?
Yes, it’s interesting. I believe it’s two generations that live a short time and the third that lives a much longer time to make the journey. Plus, they go to one place in Mexico and the study does not seem to have even mentioned changes there.
This is an example of why we have to WIN the “climate change” debate already. A species that used to be very common is now under threat of extinction. The real reason is primarily Monsanto’s poisoned crops, with other factors.
But screamers can get away with claiming ANYTHING is due to “climate change.” That distracts from handling the actual problems.
Damn it, where’s my Picard facepalm when I need it?
Oh, wait. Here it is.
http://www.rationalitynow.com/blog/wp-content/uploads/2010/05/picard-facepalm-540×432.jpg
https://scifi.stackexchange.com/questions/2013/which-episode-is-the-double-facepalm-image-macro-from
What’s that sound I hear? Is it WordPress laughing at us for thinking they wouldn’t let us down again? I think it is!
>¿<
I was OK with a lot of what the article said but the part saying that Climate Change causes milkweed to produce a different mix of cardenolides, that is less effective against monarch parasites is a little too much to swallow.
“Rising CO2 levels from the burning of fossil fuels sit at the heart of climate change, …. .”
Link to proof, please?
No, thought not.
Just more alarmist (might/possibly) hysteria
This is an interesting projection:
“But when Decker grew milkweed in a greenhouse with carbon dioxide levels of 760 parts per million (ppm)—what climate scientists project will happen in 150 to 200 years as the current level of 410 ppm continues to rise—she found that the plants produced a different mix of cardenolides, one that was less effective against monarch parasites. She published her findings in July 2018 in Ecology Letters.”
And where will the carbon come from to build up the atmosphere by 200 ppm above that is theoretically possible using all known fossil fuels plus 100%? That is quite a stretch.
There are two things wrong with this experiment – you could say omissions: she did not raise monarchs in that same environment to see if they already have epigenetic adaptations which would be invoked by the additional CO2 or by the physiology of the plant; she did not model the evolution necessary to adapt to the new conditions over 2 centuries. Perhaps they will adapt easily. The increased CO2 should lead to the eradication of the pest, based on all she told.
She is comparing the current insect and its current manifestations of epigenetic adaption with an extremely unlikely future condition. I don’t see how that is useful by itself.
There are monarch butterflies in Europe, Australia and New Zealand. They can fly across the Atlantic (and do). The normal wintering grounds are in Florida and Mexico, not so much California. The killing of their food base in the North through the use of herbicides is definitely impacting them. They used to have more food in the open pastures that were kept forest-free by humans who used fire extensively to manage the deer food supply (grasslands).
The banning of large scale use of fire as a management tool of course allowed the random regrowth of the forest (so-called second growth) with only the farmed fields kept open. So the solution it is really about maintaining habitat, not farming. Logging the new forests and burning the fields annually to keep them open – well you can guess how that will be received be ecologists who consider all actions of humans to be destructive. Nature, left to itself, would have the whole eastern half of N America covered in forests and there would be nearly no place for monarch butterflies at all. Fire managed by humans is part and parcel of the ecology of North America.
“The invisible hand of fear and dread gripped Taylor’s gut.”
Wow, a two-fer!
Not only does Carrie get to cast real gloom and doom re the monarch she also gets to make an underhanded swat at Adam Smith’s “invisible hand” meme by associating the social benefits of individual actions (i.e. “the invisible hand”) with fear and dread.
Is therer any particular reason we should give a damn that yet another species becomes extinct because of environmental changes of some sort? I mean, how many species come into being and then leave ? Hundreds of thousands? Millions? Believe me, I won’t miss this particular butterfly. I wouldn’t know one if I saw one.
All three images show butterflies on eucalypts non Californian natives perhaps they have already adapted.
Exactly what I thought. Milkweed as known in the UK and Australia is a low growing weed – 6″ to 1′ at max, with a stem containing ample amounts of white sap which leaks out when the plant is broken or cut – hence “Milk” weed. What are they doing on Eucalypts? – unfortunately I cannot recognize which Eucalypt species those shown are. Perhaps it is the Eucalypts that are killing the Monarchs?
There is probably a law in California requiring them to register. That is how they can be so precise.
The real problem is loss of habitat. The Monarch is the Milkweed Butterfly so destruction of Milkweed also results in destruction of the Milkweed Butterfly. I am now growing Milkweed in my garden and I have Monarch Butterflies as well as their caterpillars. They apparently have survived ice ages, the Holocene Optimum as well as the Eemian. Current climate change has been trivial as to what has happened over the last 600,000 years.
The reality is that the climate change we are experiencing today is caused by the sun and the oceans over which mankind has no control Despite the hype, there is no real evidence that CO2 has any effect on climate and plenty of scientific rationale to support the idea that the climate sensitivity of CO2 is zero. The climate change that we have been experiencing is so small that it takes networks of sophisticated sensors decades to even detect it. We must not confuse weather cycles with climate change. Mankind can provide more Milkweed for the Milkweed butterfly but we cannot affect the climate.
Monarch butterflies are also found in Australia thanks to their migration. They like the warmth here. If the U.S. runs out of Monarchs, we can send a few breeding couples over to restart the population. They do not like harsh cold however. Temperatures below -8°C will kill about 50% of the monarchs as they freeze to death. Ice crystals that form on the butterfly can kill it. Also if the butterflies are wet, they do not like it either and it will kill close to 80-90% of the monarchs. Monarchs can’t fly unless they can warm their muscles to 55°F. They can’t even crawl below 41°F.
I used to live in northern Oklahoma. The milkweed there grows, blooms, and goes to seed in the spring and early summer. After that, milkweed goes dormant. The monarchs I saw in the fall going south seemed to feed on wild asters and other plants. Their travels and feeding seemed to depend upon favorable winds going in the direction they were headed.
The butterfly feeds on necter from flowering plants. Any flower with Necter will do. During the catapiller stage of life they eat the leaves of the milkweed plant. The adult butterflies only lay eggs on Milkweed.
Monarch populations are in trouble — and very little is known with any degree of certainty about the causes. The intentional elimination of milkweed from the monarch’s breeding ranges is an obviously huge factor. – Nature has played a sorry trick on the monarch by limiting its larval (caterpillar) stage to a single plant host. It wasn’t really a bad ‘choice’ as milkweed is a prolific weed, producing huge numbers of seeds that are dispersed on the wind and readily take root in waste ground — like ditches and hiway verges. But now hiway verges are mowed just as milkweed flowers, ditches are kept cleared in many areas, and crops are maintained nearly weed-free.
It is blatantly FALSE that “climate change has forced the butterflies to travel longer distances as breeding grounds shift farther north.”
The monarch individuals that overwinter on the California Coast and in Mexico are not the monarchs that flew north from there in the spring. Monarchs are rather complicated: see Monarch Migration.
As a note, I have neighbors who visit roadside milkweeds Upstate New York and moved the eggs to milkweeds that they intentionally grow in their yard. They baby the plants until the young caterpillars enter the chrysalis stage. They then collect the chrysalises and protect them until the butterflies emerge a week or two later.
Years ago I started asking why many localities labelled milkweed as noxious weed. They were destroying the caterpillar’s feed source. I don’t think farmers have as much to do with this as do Weed and Pest districts. I have a patch of milkweed that I let grow in my yard for feed for the caterpillars.
Kip Hansen – you should do a post on this. The Nat Geo article is terrible and full of misinformation. Most people don’t seem to understand the difference between larval hosts (restricted to species in a few genera of what used to be the milkweed family [Asclepidaceae – now reduced to a subfamily in the Apocynaceae] – they do not depend on a single species of milkweed) and adult nectaring plants – Monarchs don’t need milkweed in autumn, they get their energy for migration from many different flowers. As you note with your link, they don’t start out in the spring and fly 3000 miles, but go through several generations that ‘breed’ their way north. California Monarchs stay pretty much in California although some crossing back and forth with other populations is suspected. The AGW ethanol scam making it profitable for farmers to plant maize on marginal land is probably as responsible or more so as Round-up ready plantings for reducing larval hosts – as well as urban sprawl. Global Warming would actually increase both the summer range and the overwintering area for Monarchs. They do fine here in Queensland (we usually call them Wanderers) and seem to have flown in on their own from New Caledonia to a heaven of milkweed weeds, cotton bush (Gomphocarpus spp. – I find Monarch caterpillars mostly on cotton bush), and some related vines and succulents that are fine larval food. And so on – you’d probably have a good time researching this and I would love to see what you find.
DaveW
Good points. Monarch butterflies are or were major pollinators in N America before the introduction of honey bees from Europe. Yes, those bees that are supposedly being wiped out by climate change are non-native invaders we like. Like us.
The butterflies are flower drinkers without much preference.
The default explanation which has become effectively the new null hypothesis is that “this too has been caused by anthropogenic global warming”.
But for this to be a scientific conjecture, rather than a chanted litany of faith, it has to be testable against an external null hypothesis that is different from the hypothesis being proposed.
How do we know, and test, that the population dynamics observed are not just the rather normal rapidly fluctuating quasi chaotic population dynamics of many or most living species within an ecosystem?
“It is easy to obtain confirmations, or verifications, for nearly every theory—if we look for confirmations. Confirmations should count only if they are the result of risky predictions… A theory which is not refutable by any conceivable event is non-scientific. Irrefutability is not a virtue of a theory (as people often think) but a vice. Every genuine test of a theory is an attempt to falsify it, or refute it.”
“In so far as a scientific statement speaks about reality, it must be falsifiable: and in so far as it is not falsifiable, it does not speak about reality.”
Karl Popper.
I had two undergraduate mentors who were good scholars and teachers. Dr. Dale Birkland was a young ecologist, and I took his first ever course in ecology. He taught me a simple and understandable concept that species with highly restricted “niches” were always at risk (low ecological valence). The monarchs dependence on milkweed was one known example – way back in 1961. Dr. Ed Mockford was a new entomologist, with whom I worked for two years. He taught me one well-established principle for insects: they are very weather dependent and typically have boom and bust population years/cycles. Any given year the monarchs could boom or bust in any region of their breeding distribution, and counts in any given wintering area could change dramatically. When one puts there two long-established principles together, climate change doesn’t even have to enter the picture. I often wonder if our modern computer nimrods have had any basic training in established axioms of the sciences they practice.
Note the warning, , Ïts not too late”, i.e. Keep the money coming for yet more research .
But lets go back to about 1980 and all of the warnings back then as to when it will be too late, and we are well past the date of our demise.
So lets stop worrying and live it up, as its “Now far too late”. Sarc of course.
MJE
”But when Decker grew milkweed in a greenhouse with carbon dioxide levels of 760 parts per million (ppm)—what climate scientists project will happen in 150 to 200 years as the current level of 410 ppm continues to rise—she found that the plants produced a different mix of cardenolides, one that was less effective against monarch parasites. She published her findings in July 2018 in Ecology Letters”.
Ha ha ha ha ha. That’s a good one!
She got one thing right then, but I could write a book about what she doesn’t know.
The stupid continues to burn and would contribute to Gorbeal Warming if it actually existed.
scientists like Obserhauser say all is not yet lost –> Oberhauser
Let me get this straight, farmers used to allow milkweed to grow in between crops? An absurd assumption.
Jon ==> Milkweed commonly grew in among crops in the MidWest — springing up after crops got too high to allow further mechanical weeding. With modern chemical weeding, there is almost no milkweed found in crop fields.