Sub-par science: Rising CO2 levels threaten Monarch butterflies by making milkweed impotent

“Controlled study” infects butterfly larva with parasites then feeds them lab-grown CO2 enhanced milkweed. Result is sub-par science.

Rising carbon dioxide levels pose a previously unrecognized threat to monarch butterflies

UNIVERSITY OF MICHIGAN

ANN ARBOR–A new study conducted at the University of Michigan reveals a previously unrecognized threat to monarch butterflies: Mounting levels of atmospheric carbon dioxide reduce the medicinal properties of milkweed plants that protect the iconic insects from disease.

Milkweed leaves contain bitter toxins that help monarchs ward off predators and parasites, and the plant is the sole food of monarch caterpillars. In a multi-year experiment at the U-M Biological Station, researchers grew four milkweed species with varying levels of those protective compounds, which are called cardenolides.

Half the plants were grown under normal carbon dioxide levels, and half of them were bathed, from dawn to dusk, in nearly twice that amount. Then the plants were fed to hundreds of monarch caterpillars.

The study showed that the most protective of the four milkweed species lost its medicinal properties when grown under elevated CO2, resulting in a steep decline in the monarch’s ability to tolerate a common parasite, as well as a lifespan reduction of one week.

The study looked solely at how elevated carbon dioxide levels alter plant chemistry and how those changes, in turn, affect interactions between monarchs and their parasites. It did not examine the climate-altering effects of the heat-trapping gas emitted when fossil fuels are burned.

“We discovered a previously unrecognized, indirect mechanism by which ongoing environmental change–in this case, rising levels of atmospheric CO2–can act on disease in monarch butterflies,” said Leslie Decker, first author of the study, which is scheduled for publication July 10 in the journal Ecology Letters.

“Our results emphasize that global environmental change may influence parasite-host interactions through changes in the medicinal properties of plants,” said Decker, who conducted the research for her doctoral dissertation in the U-M Department of Ecology and Evolutionary Biology. She is now a postdoctoral researcher at Stanford University.

U-M ecologist Mark Hunter, Decker’s dissertation adviser and co-author of the Ecology Letterspaper, said findings of the monarch study have broad implications. Many animals, including humans, use chemicals in the environment to help them control parasites and diseases. Aspirin, digitalis, Taxol and many other drugs originally came from plants.

“If elevated carbon dioxide reduces the concentration of medicines in plants that monarchs use, it could be changing the concentration of drugs for all animals that self-medicate, including humans,” said Hunter, who has studied monarchs at the U-M Biological Station, at the northern tip of Michigan’s Lower Peninsula, for more than a decade.

“When we play Russian roulette with the concentration of atmospheric gases, we are playing Russian roulette with our ability to find new medicines in nature,” he said.

Earlier work in Hunter’s lab had shown that some species of milkweed produce lower cardenolide levels when grown under elevated carbon dioxide. That finding caught the attention of Decker, who with Hunter designed a follow-up study to look at the potential impact of rising CO2 on the disease susceptibility of monarchs in the future.

They created an experimental system that allowed them to manipulate and measure all the key links in the chain: carbon dioxide levels, toxin concentrations in milkweed leaves, infection by parasites, and monarch susceptibility to those parasites. The fieldwork was conducted in 2014 and 2015.

Inside 40 growth chambers on a hilltop at the Biological Station, they exposed milkweed plants to two different carbon dioxide levels. Twenty chambers were maintained at current global CO2 concentrations of around 400 parts per million, and 20 chambers received 760 ppm of CO2, a level that could be reached well before the end of the century if the burning of fossil fuels continues unabated.

The four milkweed species differed in their levels of protective cardenolide compounds. The most protective species was Asclepias curassavica, commonly known as tropical milkweed. The chamber-raised plants were fed to monarch caterpillars, and each caterpillar got a steady diet of a single milkweed species with known carbon dioxide exposure.

Three-day-old caterpillars were also infected with carefully controlled doses of a common monarch parasite that is distantly related to the malaria pathogen. Ophryocystis elektroscirrhais a protozoan that shortens adult monarch lifespan, impedes its ability to fly and reduces the number of offspring it produces.

Over about two weeks’ time, the infected caterpillars grew to a length of about 2 inches, with striking yellow, white and black bands. Then they pupated inside a hard-shelled chrysalis for about 10 days before emerging as orange-and-black butterflies.

At their Biological Station lab, Decker and Hunter raised hundreds of adult monarchs. The lifespan of each individual–in Michigan, monarch butterflies typically live for about a month–was recorded, and the number of parasitic spores on each carcass was counted.

Piecing together all this data, the researchers were able to determine how changes in atmospheric carbon dioxide levels altered toxin concentrations in the four milkweed species and, in turn, how exposure to those plants affected the monarch’s lifespan and disease susceptibility.

The largest declines in parasite tolerance and butterfly lifespan occurred in monarchs that fed on A. curassavica, a milkweed species in which cardenolide production declined by nearly 25 percent when grown under elevated CO2.

In caterpillars that fed on A. curassavica milkweed grown under elevated CO2, tolerance to the parasite declined by a whopping 77 percent when compared to caterpillars that fed on A. curassavica grown under ambient-level CO2.

Monarchs that fed on A. curassavica grown under elevated CO2 suffered a reduction in lifespan of seven days due to parasitic infection. Parasites reduced mean lifespan by only two days for monarchs that ate A. curassavica grown under ambient CO2 levels.

“We’ve been able to show that a medicinal milkweed species loses its protective abilities under elevated carbon dioxide,” Decker said. “Our results suggest that rising CO2 will reduce the tolerance of monarch butterflies to their common parasite and will increase parasite virulence.”

In recent years, monarch populations have been declining rapidly. Most discussions of the monarch butterfly’s plight focus on habitat loss: logging of trees in the Mexican forest where monarchs spend the winter, as well as the loss of wild milkweed plants that sustain them during their annual migration across North America.

“Habitat loss, problems during migration and climate change all contribute to monarch declines,” Hunter said. “Unfortunately, our results add to that list and suggest that parasite-infected monarchs will become steadily sicker if atmospheric concentrations of CO2 continue to rise.”

###


Why this study is ridiculous.

  1. It’s not done in a natural setting, thus excluding all other natural environmental effects.
  2. The butterflies are purposely infected, rather than taking their chances in nature.
  3. The milkweed is subjected to an instant increase in CO2, instead of a process that would take decades. There’s no chance for adaptation.
  4. Like #3, no chance for adaptation of the butterflies
  5. Where’s the OTHER control group? No mention of one. Did they infect butterfly larva and NOT feed them milkweed and count the deaths. No. One wonders if the mortality rate of 77% might be similar in that scenario.
  6. Given the lack of a control group, it seems the results were pre-determined.

In my opinion, this is sub-par science. I’ve seen better science at high-school science fairs.

The study:

https://onlinelibrary.wiley.com/doi/full/10.1111/ele.13101

Elevated atmospheric concentrations of carbon dioxide reduce monarch tolerance and increase parasite virulence by altering the medicinal properties of milkweeds

Leslie E. Decker Jacobus C. de Roode Mark D. Hunter

Abstract

Hosts combat their parasites using mechanisms of resistance and tolerance, which together determine parasite virulence. Environmental factors, including diet, mediate the impact of parasites on hosts, with diet providing nutritional and medicinal properties. Here, we present the first evidence that ongoing environmental change decreases host tolerance and increases parasite virulence through a loss of dietary medicinal quality. Monarch butterflies use dietary toxins (cardenolides) to reduce the deleterious impacts of a protozoan parasite. We fed monarch larvae foliage from four milkweed species grown under either elevated or ambient CO2, and measured changes in resistance, tolerance, and virulence. The most high‐cardenolide milkweed species lost its medicinal properties under elevated CO2; monarch tolerance to infection decreased, and parasite virulence increased. Declines in medicinal quality were associated with declines in foliar concentrations of lipophilic cardenolides. Our results emphasize that global environmental change may influence parasite–host interactions through changes in the medicinal properties of plants.

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77 thoughts on “Sub-par science: Rising CO2 levels threaten Monarch butterflies by making milkweed impotent

  1. I’d say the study raises interesting points about possible unexpected consequences of higher CO2 levels and that this is something that should be investigated. It’s a big jump to conclude from this artificial set-up that this is actually happening in the wild though. To be fair, the abstract only says ‘may influence ‘.

    • ‘may’, ‘could’, ‘might’

      All words used to conceal the more likely possibility, ‘probably won’t’. Another sign that this isn’t real research, but a political hack. Similarly appalling work has been done in the field of coral development, with equally invalid methodologies.

        • I’m trying to decide if you were actually trying to say something intelligent for once, or if you are just trying to make a fool of yourself again.

      • Words like “may,” “could,” “suggests,” etc. are science-talk. It’s a basic tenet of scientific methodology that it never proves anything, but always leaves the door open for better evidence and new hypotheses to explain a phenomenon (this is true of climate science, as well). Definitive words or assertions are therefore avoided.

    • And Susan you would be the token lackey for these sloppy “scientists”?
      What always annoys me is that scarce funding going to these tools could better be directed to projects that will have a benefit to humanity.
      Plenty of projects to choose from.
      Instead they spin the wheels trying to get traction to score Global Warming points…..

      • I’m not defending this study in particular, I haven’t read it in full and don’t consider myself qualified to comment. I am saying that it is always worth finding out what happens under different conditions and not just making assumptions. There is never going to be agreement on what research money should be spent on.

    • “May influence” would be sufficient for a research grant.
      The purpose of the study is to determine whether or not it did.
      This study was never even attempted to determine that.

      • Looked to me like they reached a conclusion, then set up a study to demonstrate it. Yet another victim of “publish or perish”.

  2. Hardly sub-par. More like appalling, corrupt and ‘research’ commissioned with a predetermined result.

  3. Anyone who claims we are playing “ Russian Roulette” with the gases in the atmosphere might usefully consider how butterflies managed when gas mixtures in the planet’s atmosphere were different in the past.
    This looks like torturing butterflies until they scream.

    • “might usefully consider how butterflies managed when gas mixtures in the planet’s atmosphere were different in the past.”

      Why? Species evolve.

    • Fifth stanza (paragraph?)

      When the music’s over
      Turn out the light.

      The music is your special friend
      Dance on fire as it intends
      Music is your only friend
      Until the end.

      Cancel my subscription to the
      Resurrection,
      Send my credentials to the
      House of Detention
      I got some friends inside.

      The face in the mirror won’t stop,
      The girl in the window won’t drop,
      A feast of friends–
      “Alive!” she cried,
      Waiting for me
      Outside!

      Before I sink
      Into the big sleep,
      I want to hear
      the scream
      of the butterfly.

      Come back, baby
      Back into my arm.
      We’re getting tired of waiting around,
      Waiting around
      with our heads to the ground.

      I hear a very gentle sound.

      What have they done to the earth?
      What have they done to our fair sister?
      Ravaged and plundered
      and ripped her and bit her
      Stuck her with knives
      in the side of the dawn
      and tied her with fences
      and dragged her down.

      I hear a very gentle sound,

      With your ear down to the ground–
      We want the world and we want it
      Now!

      Persian night!
      See the light!
      Save us!
      Jesus!
      Save us!

      So when the music’s over,
      Turn out the lights.

      The music is your special friend
      Dance on fire as it intends
      Music is your only friend
      Until the end
      Until the end
      Until
      THE END!

      The Doors – When the music’s over.

  4. The other obvious — to me — question is what was the effect of raised CO2 levels on the parasite because if they were affected in the same way as the plant we could be back to square one.

    • The monarchs (and their parasites) were not raised at different CO2 levels. There is no theoretical reason I know of to suspect there would be any direct effect. Can you suggest one?

        • Actually 520 generations. Monarchs go through four generations per year with the 4th generation making the migration south for winter.

          • The study says we are may hit 760ppm before the end of the century.
            Alley claims that it will take us 130 years to hit 700.

            Can’t the alarmists get their acts together?

    • Also, would not fewer Monarchs frequent these strains of milkweeds thus reducing there number and causing the Monarchs to look elsewhere?

      • Obviously. If one of the four plants has this problem, surviving monarchs won’t eat them as much. Darwinian evolution in action in the field(s).

        There is probably a symbiotic benefit the plants get from the nibbling by the caterpillars. If the plants can adapt, they will do so for their benefit from the interaction. Don’t assume it is a one-way street. Any species that is single-food dependent has to be bringing something to the party or the plant would create better defences.

  5. I’ve spent a very long time, over 20 years in the presence of monarchs and milkweeds and I can say they’re very picky about the plants they choose to lay eggs on. The parents will slowly go around the garden landing on plant after plant before making the decision to lay an egg -my best guess is given their highly capable chemosensors they’re picking plants with appropriate nutritional needs for their offspring.

    • That is the first point about why the study is ridiculous.

      It’s not done in a natural setting, thus excluding all other natural environmental effects.

      Reductionism is a powerful tool. link It means we change one variable, while holding the others constant, and observe the resulting change. Reductionism’s counterpart is holism which is based on the idea that the whole is greater than the sum of its parts.

      Reductionism allows us to ask a clear question and get a clear answer. As your observation about the egg laying behavior of Monarchs demonstrates, the reductionist answer, although clear, may be wrong. In that light, I am reminded of Einstein’s quote which is paraphrased as:

      Everything Should Be Made as Simple as Possible, But Not Simpler link

    • The other mis-step in the research was that the range of the Monarch Butterfly and that of the one milkweed variant mentioned overlap only over Mexico, the extreme southern end of the Monarch’s range. So one must wonder just how many of these anemic milkweed variants the Monarchs encounter, and why wouldn’t they simply choose the variants they prefer?

      BTW wouldn’t the caterpillars, plants and parasites all be exposed to the higher CO2 environments simultaneously? Were there any growth differences between the caterpillar groups? Did the plants have any differences (probably larger) beyond the one chemical they were looking for? What was the mortality rate for the butterflies who ate two different versions of A. curassavica? Was that even tested?

      • Well Mexico is where they overwinter so that could be an important species Also the Monarch is in decline so it would be good to find out why, -60%+ in the last 20 years.

        • Phil: Has not much of the milkweed bordering the crop fields the Monarchs flew over been replaced by corn for bio-fuels? Also, Ivanpah and other such solar installations have killed off a certain percentage of the Monarchs.

          • Phil: Has not much of the milkweed bordering the crop fields the Monarchs flew over been replaced by corn for bio-fuels?
            I doubt it, corn requires good soil to grow in and why would they grow it in the borders to the crop fields. Far more likely that the milkweed has been impacted by weedkiller usage.

            Also, Ivanpah and other such solar installations have killed off a certain percentage of the Monarchs.

            There are not many such installations and Ivanpah is in the Mojave desert, not on the Monarch migration route.

      • … and temperature/humidity of the study, as compared to typical temp that the tropical milkweed variety is looking for.

        I need to obtain a grant so I can do the same thing in the tropics … maybe Bali.

  6. “We discovered a previously unrecognized, indirect mechanism……….”

    No, you went looking for it and designed a process (badly it seems) to demonstrate it.

    A far cry from ‘discovering’. Fleming ‘discovered’ penicillin, by accident in 1928, and thanks to his observational and deductive skills he realised what was happening and wrote a paper on it, but didn’t have the resources to pursue it.

    His discovery would have gone unrecognised had his paper not been ‘discovered’ by Dr. Howard Florey at Oxford University in 1938 whilst leafing through back copies of The British Journal of Experimental Pathology.

    Florey had the resources and manpower to develop penicillin.

    These are ‘discoveries’, in this case, a series of coincidental accidents.

    • “No, you went looking for it and designed a process (badly it seems) to demonstrate it.”

      They went looking for it? Badly? It’s great to see so many people understand the research. You must have been there.

      • The scientific method is that you propose a hypothesis then carry out experiments to test that hypothesis. That looks like what was done here.

  7. Where’s the OTHER control group? No mention of one. Did they infect butterfly larva and NOT feed them milkweed and count the deaths. No. One wonders if the mortality rate of 77% might be similar in that scenario.

    As far as I know their only food is milkweed. Shouldn’t the mortality be 100%.

    • If they destroy a milkweed plant I am told that you can finish the grub off on pumpkin.

  8. 7. The probability that CO2 concentration will reach 760 ppm is extremely low. The fossil fuel resource quality isn’t there to allow us to burn at a pace required to reach such high concentrations.

  9. The real problem that the butterfly’s face is not more CO2 in the atmosphere but habitat reduction by means of the destruction of wild milkweed.

    • I dunno. There very well might be destruction in some areas, but at least the areas I observe in western Maryland/south-central Pennsylvania there is quite alot of milkweed easily visible along the rural roads. But there are definitely less Monarchs.

  10. Subpar? Odd that today’s non-scientist gets to determine what is real and what is subpar. No wonder we’re in such a weird position with science in the US. Everyone has an opinion, but today the lay opinion counts more than the science to a large percentage of the population.

    • As usual, blatant appeal to authority.
      Not even once have you ever attempted to actually engage those you disagree with. You just shout that those you consider experts disagree therefore everyone else is wrong.

  11. I may not have understood your last point, but if you took a group of Monarch caterpillars and did not feed them milkweed, the mortality rate would be 100%.

  12. More stupidity. Monarchs are hurting because the small areas of mountain forests in Mexico where they over-winter are being cut down.

  13. It is the resurgent milkweed population that makes me worry about our local Monarch population. Milkweed locally is on its way to become a nuisance.

    I have noticed that what we call Common Mullein and Milkweed do not seem to intermingle. One sees patches of one or the other, perhaps even abutting adjacent, but not mixed that I have noticed.

    I see Monarch butterflies by the ones and twos, not a group that I recall for a long time.

  14. The self-importance and arrogance of these people is simply breathtaking…
    Where to start:
    Milkweed does not make ‘that stuff’ for the benefit of the butterflies (unless they are vital pollinators or seed dispersers) The milkweed is trying to protect itself from being eaten.

    Aspirin. Vital medicine? Don’t make me laugh.
    Used for curing headaches maybe. And the bad-head is caused by what – surely not a symptom of dehydration brought on by eating sugar? Oh No. How many headache pills are popped daily in the Western World – hundreds of millions if not billions when a glass of water would do the trick.
    Ah. Is that why you always wash the pills down with a drink? A Penny drops.
    Also slows the blood clotting process, even at very low doses. For supposedly outgoing and adventurous types (hunter gatherers like us) is that REALLY a good idea?
    Otherwise the very definition of Gut Rot. (It actually does it from the outside in, NOT as almost everyone imagines horrid little pills burning holes from the inside out)

    Digitalis. A desperate poison. Used to control abnormal heart rhythm – Atrial Fibrillation (AF)
    Fine. But did not the ingestion of large amounts of either/both nicotine and alcohol (more desperately toxic plant derived poisons) cause the AF in the first place?

    Taxol: Horribly horribly poisonous used to ‘cure’ cancer. And the cancer came from, oxidative stress brought on by eating so much sugar. Plus the barrage of random pot-shots that unsaturated fats (plant oils) take at our DNA when those bonds break open in all the wrong places/times/situations.
    Plant oils? Type of fat? Fat processing creatures? Mammalian females? Certain parts of same?
    Oooooooh. Getting expensive coz there goes another penny

    There are a group of folks out there, admittedly folks selling ‘health products, who will tell you that- to get the same amount of Vitamin A that our grandparents got by eating one orange, we would need to eat six oranges.
    Nothing to do with carbonoxide.
    Everything to do with soil erosion. =over-farming brought on by the (wilful?) ignorance of what happens under our feet.
    Oh no. Not another penny!…. Vitamin A?……..Golden Rice anyone..

  15. “I’ve seen better science at high-school science fairs.” I have in the past. Not so sure about these days. I’ve also seen much worse.

    Declaring milkweed a noxious weed hit the butterflies probably harder than anything else. Yet few discuss that. The error appears to be being corrected now. I have a patch of milkweed just for the butterflies. If it spreads too far, I’ll cut some of it out. It is possible to have butterflies and a nice yard both.

  16. Looks like one of the researchers used the study for her PhD dissertation. So, welcome another learned academic to the the fold of alarmist “experts”.

  17. Piecing together all this data, the researchers were able to determine how changes in atmospheric carbon dioxide levels altered toxin concentrations in the four milkweed species and, in turn, how exposure to those plants affected the monarch’s lifespan and disease susceptibility.

    ABRUPT changes in CO2, that is. They didn’t control for the time element between 400 ppm and 760 ppm CO2 levels and therefore cast significant doubt on any interpretation of results. Give the plants a super-rich diet and they will react in one way; slowly boost their intake and they very well may react differently. You don’t know until you test it.

    • Gary: Agreed. They should have put 5 of those units aside for growing a 550 ppm batch to show that the effect is cut by half if they do. It would also show if the effect is non-linear, and at the top or at the bottom. Maybe its the first 50 ppm wot dunnit, or the last 50. The experiment should be repeated – send money.

  18. There is a long literature showing that plants change their production of secondary chemicals in response to being grazed. The chemicals in question are bulk poisons to deter grazing.

    That being the case, were the plants grown in enriched atmospheres growing faster than the controls? If so, small wonder that they produce fewer secondary chemicals. They have not received cues to tell them to up the production. If they are chomped more, they make more. Monarchs carefully choose their hosts. Do they choose intact or previously-chomped plants?

    Furthermore, monarchs are also *negatively* affected by milkweed poisons. You thought they just sequester it all to make themselves unpalatable as adults? No. There is presumably a happy medium here somewhere, whereby the monarchs obtain enough of the relevant chemical but not too much.

    This toxic effect is probably most pronounced in the youngest larvae, which almost certainly would benefit from feeding on the milkweeds with the lower levels of chemicals.

    I am dubious about the results. Maybe at the biome level they could be trusted. But who has a dozen biomes to rub together to do such experiments?

  19. Did the study find any individuals who seemed to be not affected? Where is everyone’s faith in natural selection?

  20. Without reading the paper and knowing very little about this I would however offer the following.
    “1. It’s not done in a natural setting, thus excluding all other natural environmental effects.
    2. The butterflies are purposely infected, rather than taking their chances in nature.”
    Experimental isolation from all other environmental factors is important in parasitology to avoid confounding factors. Ambient concentrations would be a control, probably not adequate, but this does not disqualify their science by itself. Verification of extrapolations made from experimental studies is always necessary.

    This may be a lousy paper with obvious bias and the abstract is clearly inadequate. (“Our results emphasize that global environmental change may influence parasite–host interactions through changes in the medicinal properties of plants.”). My major mentor was a parasitologist and would not have allowed this extension, therefore the irrelevant statement which seems to commonly appear nowadays. As noted the paper may well have similar signs of problems in its experimental design. Loss of classical parasitology understanding has been lamented in the discipline.

  21. Should we note that the “study” engulfs an existing/current species with extreme levels of CO2 and surmises the results as relevant, but does not (admittedly without having read the study)…. but as Anthony points out, there has been no allowance for adaptation, either after OR before changes in atmospheric CO2. Not only the milkweed suddenly exposed to increased levels without adaptation, but there is nothing to show what the milkweed’s potency was during the time when CO2 levels were significantly lower.
    This study would suggest that potency becomes lower as CO2 becomes higher, yet there is no evidence to support that assumption.

  22. 1 and 2 are normal experimental design steps. Hence are limiting but allow research that focuses on fewer factors.
    3 and 4 are valid.

    5 is not valid as monarch larvae eat ONLY milkweed. They feed all milkweed, they infected all larvae.

  23. “we are playing Russian roulette with our ability to find new medicines in nature,”

    This “study” only showed a drop in concentration for the first generation.
    1) We don’t know what will happen in future generations.
    2) A drop in concentration does not mean the “medicine” is gone, so we aren’t playing Russian roulette with anything.
    3) An emotion laden term like “Russian roulette” has no place in a paper claiming to do science.

  24. Consumption of cardenolides (a toxin, as noted) has negative effects on growth and fecundity of the uninfected butterflies. Healthy female butterflies eating too much of the high cardenolide Milkweeds have lower survival rates. It is only in the infected butterfly setting that there is a threshold between too little and too much. The milkweeds produce the toxin to prevent themselves from being over-consumed. It is an evolved struggle between the plant and the herbivores that would eat it to the roots without defenses.

    https://www.thoughtco.com/monarchs-dont-get-sick-eating-milkweed-1968216

    “Finally, there’s the problem of the toxic milkweed cardenolides. Contrary to the story often told about monarchs and milkweed, the evidence suggests that monarch caterpillars can and do suffer the effects of consuming cardiac glycosides. Different species of milkweeds, or even different individual plants within a species, can vary significantly in their cardenolide levels. Caterpillars feeding on milkweeds with high levels of cardenolides have lower survival rates. Studies have shown that female butterflies generally* prefer to oviposit their eggs on milkweed plants with lower (intermediate) cardenolide levels. If the ingestion of cardiac glycosides was wholly beneficial to their offspring, you would expect females to seek host plants with the highest toxicity.

    This is common in nature. For example, Arsenic was used going back to the time of Hippocrates to treat all sorts of ailments with varying degrees of success. Before the era of effective antibiotics arrived in the 20th Century, arsenic compounds were known as the “Savior from Syphillis.”
    There is a threshold though that can be quickly crossed with Arsenic compounds to chronic toxicity to the patient. Even today, Arsenic is used to treat and cure otherwise un-treatable trypanosomiasis. But using arsenic as a medicinal must be carefully monitored.

    Another toxic compound noted in the Press Release, taxol, is used as a naturally found chemotherapeutic agent for certain cancers. But make no mistake, taxol is toxic. Healthy people should not take taxol. It has severe side-effects.

    Belladona nightshadeis also very toxic. But at low doses can have medicinal effects because of its atropine-like effects to reduce spasmotic bowel episodes.
    https://www.homeremediess.com/belladonna-deadly-nightshade-atropa-belladonna-medicinal-uses-images/

  25. “Rising carbon dioxide levels pose a previously unrecognized threat to monarch butterflies”

    TRANSLATION: “The polar bear thing still doesn’t seem to be working.”

  26. Hopelessly inadequate experimental design because of lack of appropriate control groups. Any insect toxicologist peer reviewing the MSS or mentoring the student would have shredded it on that shortcoming alone. (retired insect toxicologist)

  27. I call bullsh!t and I will not waste any more time on this ridiculous paper.

    Here is my recommended approach to global warming alarmist nonsense:

    https://wattsupwiththat.com/2018/07/05/scott-pruitt-out-at-epa/#comment-2401030

    My rejection of warmist propaganda is a practical accommodation of Brandolini’s Law, which states that:

    “THE AMOUNT OF ENERGY NEEDED TO REFUTE BULLSH!T IS AN ORDER OF MAGNITUDE BIGGER THAN TO PRODUCE IT.”
    – Alberto Brandolini, 11 January 2013

    One year earlier, I published the following statement [Note that it is still true, after more than two decades of warmist propaganda]:

    “After more than a decade, NONE of the scary predictions of the global warming alarmists have materialized. The warmists’ predictive track record is one of absolute failure.”

    “BASED ON THE WARMISTS’ DISMAL TRACK RECORD, ONE CAN SAFELY ASSUME THAT EVERYTHING THEY PREDICT IS HIGHLY LIKELY TO BE FALSE.”
    – Allan M.R. MacRae, January 15, 2012
    https://wattsupwiththat.com/2012/01/14/tisdale-on-foster-and-rahmstorf-take-2/#comment-748715

    Notwithstanding their reverse order of occurrence, you can call my above statement “MacRae’s Corollary to Brandolini’s Law”.

    “MacRae’s Corollary” is designed to save you countless hours of toil, as evidenced by the ~decade of diligent work and remarkable mathematical competence that Steve McIntyre expended to disprove Mann’s “hockey stick” (aka “hokey stick”).

    Just assume that the warmists are hopeless pathological liars, and that all their very-scary predictions of runaway global warming, wilder weather, etc are false. You will have a very high probability of being correct.

    Regards, Allan 🙂

      • Thank you John H for your question; here is my answer:

        BACKGROUND INFORMATION:

        BRANDOLINI’S LAW states:

        “THE AMOUNT OF ENERGY NEEDED TO REFUTE BULLSH!T IS AN ORDER OF MAGNITUDE BIGGER THAN TO PRODUCE IT.”
        – Alberto Brandolini, 11 January 2013

        MACRAE’S COROLLARY TO BRANDOLINI’S LAW states:

        “BASED ON THE WARMISTS’ DISMAL TRACK RECORD, ONE CAN SAFELY ASSUME THAT EVERYTHING THEY PREDICT IS HIGHLY LIKELY TO BE FALSE.”
        – Allan M.R. MacRae, January 15, 2012

        THE STATISTICAL BASIS FOR MACRAE’S COROLLARY TO BRANDOLINI’S LAW:

        First, assume that warmist bullsh!t is normally distributed. This is risky, because warmists are not normal, and neither is their bullsh!t.

        To date, the warmists have been wrong about every very-scary prediction of runaway global warming and wilder weather, etc, and are operating at more than +/-3σ, or 3 standard deviations from the mean. such that warmists are at least 99.7% full of bullsh!t.

        Recognizing that the warmists might actually want to slip-in a bit of truth as a tactical measure to improve their shattered credibility, conservatively assume +/-2σ, or 2 standard deviations from the mean. such that they are at least 95% full of bullsh!t.

        In conclusion, +/-3σ is accurate to date, but +/-2σ is more charitable.

  28. Thoroughly absurd!

    1) Three species of milkweed are grown under two conditions of CO₂

    2) Milkweed plants are harvested, separated by species and fed to monarch caterpillars.

    3) The monarch caterpillars are “inoculated” with spores of “parasites”. I must admit to being puzzled by what parasites, except fungi or viruses, are transmitted via spores.

    4) Then these characters chart caterpillar response to their parasites.

    5) From these charts the alleged researchers assume milkweed medicinal loads based on caterpillar parasite loads/survival.

    6) From their caterpillar measurements, statistical analyses are performed and p values calculated.

    A) Whatever happened to direct qualitative and quantitative testing of the milkweed plant toxins?

    B) Whatever happened to monarch caterpillars living on and eating milkweed directly?
    * a) Eliminating issues with delays or hazards between harvesting milkweed and feeding caterpillars.
    * b) Eliminating issues with harvested plants left in sunlight, rinsed by rain, kept in hot locations.

    C) Isn’t it amazing that these researchers fail to validate or verify their inoculation procedures and success, before jumping to assuming parasite effects?

    etc. etc. It’s just another Sophomoric High School level pretense research pretense.

    • 3) The monarch caterpillars are “inoculated” with spores of “parasites”. I must admit to being puzzled by what parasites, except fungi or viruses, are transmitted via spores.

      Perhaps you should read the paper? It’s a protozoan parasite, Ophryocystis elektroscirrha.”

      A) Whatever happened to direct qualitative and quantitative testing of the milkweed plant toxins?

      They did it: “On the same day as inoculations, we sampled milkweed cardenolide and nutrient concentrations using established methods (Zehnder & Hunter 2009; Tao & Hunter 2012).”

      C) Isn’t it amazing that these researchers fail to validate or verify their inoculation procedures and success, before jumping to assuming parasite effects?

      Really, what makes you think that they didn’t do so? Perhaps you should have read the paper?
      “After death, infection success and spore loads were measured from adults following established methods (de Roode et al. 2008a,”

      This would appear to be a sophomoric level attack on the study by someone who didn’t actually read it!

  29. They also present their data very poorly. Of the nine files of supporting information the one graphical representation had error bars like a wizards sleeve. I can hardly type for laughing.

  30. “…and 20 chambers received 760 ppm of CO2, a level that could be reached well before the end of the century if the burning of fossil fuels continues unabated.”

    There is no evidence to support that at all. The study is complete rubbish!

  31. There’s a different flaw that I didn’t notice anyone mentioning. The whole “more CO2 makes less nutritious plants” thing is always reported as strictly a matter of percentage. With more CO2, plants grow much larger, and presumably have more total nutrition.

    But put in the total size as a denominator and you might be able to say that some vitamins and other chemicals are less “concentrated.” That’s not surprising. Still, reporting only the concentration while being careful to avoid mentioning that the total vitamins (or whatever chemicals) has increased is a bit disingenuous.

    So, how does this relate to the monarch study? They had an environment where all the monarchs were perfectly well fed. There were no food shortages or limitations of any kind. This is where the extra CO2 would have helped the real world Monarch population a lot more than any lowered concentrations might have hurt.

  32. Poorly designed experiments seem to be standard fare now days. That they get published at all is a mystery but in a peer reviewed journal is a bit bizarre.

    I live on the migratory flyway for monarchs, though we have some monarchs from spring through winter. We also plant milkweed specifically for monarchs. One of the things we have noted is that not only do monarchs feed on milkweed but so do several other specific insect species, a bug, a beetle, and an aphid. Those insect often show up earlier than monarch larvae on the plant. We know from published research that when a plant is attacked by pests they increase their chemical defenses. In other words a plant where insect pests are excluded may not produce the same level of chemical protection as one being bombarded by pest.

    I didn’t read the entire paper but what is the mechanism by which milkweed does not produce as much chemical protection at higher levels of CO2 in a closed environment?

    Not having a control is never a good thing.

  33. Anthony Watts : “sub-par science “………………..,WHY are you being so kind ?
    This was absolutely NOT science……..NO CONTROL GROUP !
    Automatic FAIL !!
    This was just inhuman treatment of butterflies…….where are the ANIMAL RIGHTS ACTIVISTS
    PROTESTING THIS ACTION ??????
    IF DECKER WAS AWARDED A DOCTORATE BASED ON THIS “STUFF-UP” THEN
    ” Decker, who conducted the research for her doctoral dissertation in the U-M Department of Ecology and Evolutionary Biology. She is now a postdoctoral researcher at Stanford University.”
    SHOULD BE STRIPPED OF THE DOCTORATE on the basis that it devalues ALL the
    other doctorates they have awarded !
    This “evidence” is about as substantial as the Feminist-Movements “Lived Experience ” malarkey !

  34. Rocket scientist identified the main problem with the study, that “Tropical Milkweed,” A. curassavica, does not occur where the study was conducted or in most of the United States and is just one of 4 species of milkweed that are host plants for Monarch caterpillars. It also has other problems as a Monarch host plant- https://monarchbutterflygarden.net/is-tropical-milkweed-killing-monarch-butterflies/ Common Milkweed, both A. exaltata (in the east) and A. speciosa (in the west). are the host plant for most Monarch cats in the U.S. Because of modern farming with genetically modified crops immune to herbicides, both Common milkweed and nectaring flowers for bees. butterflies and other insects are reducing the range and populations of these important pollinators. Almost everything except the genetically modified crop is killed. That is a known problem.

    The study, as noted, also needs a control before any conclusions can be inferred. I do butterfly studies and have online butterfly field guides to South Carolina and the Yucatan Peninsula that you can find by clicking on my website- https://sites.google.com/site/southcarolinauplandbutterflies/

  35. “1. It’s not done in a natural setting, thus excluding all other natural environmental effects.”

    Exactly. This is to study a particular effect. It’s extremely hard indeed to find milkweed growing naturally at 760 ppm CO2.

    “2. The butterflies are purposely infected, rather than taking their chances in nature.”

    The researchers have to infect every monarch with a known, realistic quantity of parasite, since it’s the effect of increased CO2 on milkweed cardenolides and how that in turn affects the parasite-mediated longevity of the monarchs, not the effect of initial parasite load or how many butterflies have the parasite in nature or predation rates, etc.

    “3. The milkweed is subjected to an instant increase in CO2, instead of a process that would take decades. There’s no chance for adaptation. (and point 4)”

    True. This is a limitation to the study. Unfortunately, there are always going to be limited opportunities to study what organisms might be like 80 years from now. For the same reason, we can’t be sure that increased CO2 levels will always increase growth and water use efficiency of most plants.

    ‘”5. Where’s the OTHER control group? No mention of one. Did they infect butterfly larva and NOT feed them milkweed and count the deaths. No. One wonders if the mortality rate of 77% might be similar in that scenario.”

    Given that milkweed is the sole food of monarchs (2nd paragraph), it’s pretty likely the outcome would be a 100% mortality rate.

    “Given the lack of a control group, it seems the results were pre-determined.”

    The control groups are monarchs fed the milkweed grown at 400 ppm. Apart from other research, there is no a priori reason to expect the plant grown at higher levels to influence monarch mortality.

    Based on the PR and abstract, I see no problems with the study design. There are caveats such as evolutionary potential, but that is not a problem with experimental design but with the fact that we can’t see the future. It’s normal for scientific research to have caveats and limitations; that doesn’t mean it’s sub-par. This is evidence, not “proof.”

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