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I didn't know caterpillars turned into goo...
August 8, 2012 6:30 PM   Subscribe


 
Mitochondria? That's the one thought to have originated from symbiosis, right?
posted by cmoj at 6:35 PM on August 8, 2012


Yeah, but mitochondria are always with us. The idea Bernd Heinrich is proposing here is that transformation is a way two different creatures can share the same body. Caterpillar lives a full life, cocoons itself, dies, turns to mush. Butterfly genes switch on and use mush to build a butterfly.

Heinrich's saying that caterpillars and butterflies somehow "mated" in the past and now share the same DNA, but remain different species. The biggest problem with this idea that I can see is that butterflies do all the mating. If they were truly separate animals, then why would the caterpillar genes just ride along and let butterflies carry their genes into the future. There'd be no selection pressure on the caterpillar at all.
posted by Kevin Street at 6:43 PM on August 8, 2012 [4 favorites]


Previously.
posted by Sys Rq at 6:43 PM on August 8, 2012


It's not science until Heinrich performs an experiment to verify his hypothesis that moths and caterpillars are two different animals altogether. Until then, he's just playing with semantics. The prologue is ridiculous too, acting as if he's some revere-Galileo that the scientific establishment is out to lynch.
posted by axiom at 6:44 PM on August 8, 2012 [3 favorites]


Erm, epilogue...
posted by axiom at 6:45 PM on August 8, 2012


Actual scientists seem even more unimpressed:

http://phylogenomics.blogspot.com/2012/08/uggh-robert-krulwich-blogs-about.html

posted by adamsc at 6:47 PM on August 8, 2012 [1 favorite]


"The idea Bernd Heinrich is proposing here is that transformation is a way two different creatures can share the same body."

Isn't the point better put by saying that they share the same building material to form different bodies?
posted by oddman at 6:48 PM on August 8, 2012


I think an analysis of which genes are turned on when would be illuminating here. Things get swapped around a lot, but there might still be a statistically significant skew if, say, at one point an insect egg took on some entire worm chromosomes.
posted by dunkadunc at 6:49 PM on August 8, 2012 [2 favorites]


Yes, that's a better way of putting it, oddman. I guess what they'd share is the same chromosomes, with one half activated in the first life, and the other half activated in the second.
posted by Kevin Street at 6:50 PM on August 8, 2012


Originally drafted for publication in Proceedings of the International Society of Dude. Wait, What?

I'm not a biologist, so I defer; it doesn't sound like much good to me anyway. And it seems like the question itself is meaningless. What this creature is, is one entity, and it breeds true. Even if this theory turned out to be true, why should it matter that the creature has radically different life stages?
posted by Countess Elena at 6:50 PM on August 8, 2012 [2 favorites]


The amazing thing is that caterpillars do turn into butterflies this way, by mushifying and turning on different genes to rebuild themselves. Heinrich is saying that they do it because they're two different animals, which, if true, would open up the idea that other animals besides bugs might do the same thing. (Or could be made to do the same thing with some alterations.) Like the author of the blog said: dandelions into pine trees, tadpoles into catfish. You could have lions turn into lambs, or vice versa, depending upon which species was most numerous. Grass becoming trees if the weather patterns change, and so on. A biosphere capable of rapid transformations to meet changed conditions.
posted by Kevin Street at 6:57 PM on August 8, 2012 [1 favorite]


I actually think that this has merit. I also think that in a million years, human legs will fall off half-way through their lifecycle, then turn into dogs.
posted by It's Raining Florence Henderson at 6:58 PM on August 8, 2012 [7 favorites]


This is my like my theory that our frontal lobes aren't actually a natural evolution but a sluglike alien species that rides our bodies like a horse.
posted by Bunny Ultramod at 6:59 PM on August 8, 2012 [21 favorites]


Well, it's a creative idea...dunno on the science, but the overall concept kinda sounds like it would make sense.
posted by jenfullmoon at 6:59 PM on August 8, 2012


That shit is mind blowing. Do we know for a fact there wasn't a baby butterfly inside the caterpiller the whole time the way there are billions of organisms living in and on the human body ? Also, if the goop can reform into a butterfly, can it be said that it is dead? At may be goop, but it is living goop. I myself wait for the day when I can turn into goop and pour myself into a nice comfy chair.
posted by Ad hominem at 7:00 PM on August 8, 2012 [3 favorites]


The idea Bernd Heinrich is proposing here...

It's not science until Heinrich performs an experiment to verify his hypothesis...

To his credit, if he deserves any, this isn't Heinrich's idea; it's Donald Williamson's.
posted by Sys Rq at 7:01 PM on August 8, 2012


They're one animal with two different personalities, and everyone gets this wrong. And I mean EVERYBODY.
posted by Eyebeams at 7:03 PM on August 8, 2012 [36 favorites]


DNA doesn't work like that. You can't just mate two not-even-very-closely-related species and get some kind of chimeric hybrid. The mitochondria/chloroplast thing is a different path, it's a path of increasingly intimate symbiosis not of some kind of barrier breakdown resulting in a two-phase lifeform.

Also, caterpillars don't die and turn into butterflies, they stay alive and turn into butterflies. A pupa is most definitely alive, there's no loss of continuity. And it's not just butterflies, it's actually most insects, except that there is a major division of insects that only do a partial transformation which just goes to show that this metamorphosis thing wasn't just a weird one-time fluke but rather the product of an evolutionary process with lots of phases in between.

I mean, a zygote doesn't look anything like an adult human. Does that mean that what we think of as humans is the result of an ancient mating between a zygote-like species and an adult-human-like species? Ridiculous.

The whole theory is a fantasy, it's totally unsupported. And just because someone published a speculative paper about it which hasn't been retracted doesn't mean it's plausible -- the barrier for retraction is actually higher than just most scientists thinking that something is obviously wrong. There generally has to be some kind of serious methodological flaw or some kind of actual malfeasance involved, such that a paper which people would otherwise be inclined to take seriously is shown to be wrong in a way that actually would cause harm if people followed its conclusions. Nobody is going to be following these conclusions because firstly they're not conclusions and secondly they're clearly fanciful and not worth consideration as a serious theory.

Things like this get published because they are provocative and might contain some grain of inspiration that kicks off a only-very-tangentially-related line of real research. Mostly because they're provocative though.
posted by Scientist at 7:04 PM on August 8, 2012 [36 favorites]


Are there butterfly-like creatures that don't go through a larval stage?

I don't think it's a wildly mplausible theory on its face, though. Imagine something like a parasitic wasp that lays eggs into a worm like creature. Billion to one chance, DNA crosses over, and you get a hybrid.
posted by empath at 7:04 PM on August 8, 2012


It's not science until Heinrich performs an experiment to verify his hypothesis...

Mapping the genome during larval and adult phase should do the trick.
posted by Slap*Happy at 7:06 PM on August 8, 2012


Does that mean that what we think of as humans is the result of an ancient mating between a zygote-like species and an adult-human-like species?

Yes. That's what it means. We were young and in love.
posted by It's Raining Florence Henderson at 7:07 PM on August 8, 2012 [7 favorites]


But I do think there are a lot of problems with it... For example, where did cocoons come from?
posted by empath at 7:08 PM on August 8, 2012


Florida.
posted by It's Raining Florence Henderson at 7:08 PM on August 8, 2012 [5 favorites]


why would the caterpillar genes just ride along and let butterflies carry their genes into the future.

Because the butterflies are going to make more caterpillars? This is kind of like asking why women's DNA would ever produce men.

In fact, maybe that's the way to look at it. It's kind of like sexual reproduction, but with the mates time-shifted rather than space-shifted.
posted by DU at 7:08 PM on August 8, 2012


Eat your oatmeal.
posted by It's Raining Florence Henderson at 7:08 PM on August 8, 2012 [3 favorites]


Heh. This is the theory that killed non-reviewed academy member submissions to PNAS. The crank factor is pretty high here.
posted by mr_roboto at 7:09 PM on August 8, 2012 [8 favorites]


Cocoon storks.
posted by sendai sleep master at 7:09 PM on August 8, 2012


So I was a caterpillar for awhile and did a couple semesters at butterfly school; maybe I can help out with some of this. Puberty was pretty rough on all of us back then. My appetite was out of control. I remember gorging myself on just about everything I could find. It started with healthy stuff but eventually I just ate everything-- cake, ice cream, pickles, swiss cheese, salami, cherry pie, sausage-- you name it I ate it. I didn't feel good at all. I guess in retrospect it was really just stress eating, or exercising control over the one area of my life where I *had* any control.

And sure, there were nights when I truly wished I were dead. I spent so much time in my room that many of my closest friends thought I was dead. Most days I couldn't even get out of bed, but I want to be emphatic here: I was not dead. None of us were. You should have seen us at the 5-year reunion. It was incredible.
posted by The White Hat at 7:09 PM on August 8, 2012 [18 favorites]


Imagine something like a parasitic wasp that lays eggs into a worm like creature. Billion to one chance, DNA crosses over, and you get a hybrid.

Right. But, like, a liger isn't a lion for the first half of its life and a tiger the second half, with a big, complicated process of metamorphosis in between.

It's all pretty ridiculous.
posted by Sys Rq at 7:10 PM on August 8, 2012


Are there butterfly-like creatures that don't go through a larval stage?

Cockroaches, dragonflies, lots of insects. Not the majority of them, but many of them. They are born as nymphs which are not larval but not fully adult (they resemble the adults but lack, among other things, wings and genitals) and become progressively more adult-like with each moulting until they reach their final stage at which point they have wings and genitalia. Nothing in lepidoptera though, no. You have to go a bit further back on the tree. That's your evolutionary transition right there, though.
posted by Scientist at 7:10 PM on August 8, 2012 [4 favorites]


Or, you know, what Scientist said.
posted by The White Hat at 7:10 PM on August 8, 2012


I came to say that the hand drawn illustrations by Krulwich are charming.
posted by noway at 7:11 PM on August 8, 2012


Humans carry all kinds of virus DNA, we didn't let them do shit. I still dont really buy this though. It is clearly one animal with a multitude of forms from caterpillar to goop in a pod to butterfly. All animals change in some ways over time.
posted by Ad hominem at 7:13 PM on August 8, 2012


Hey, check out the comments on the NPR.org article, though. Williamson is in there arguing directly with the guys who wrote the refutation of his PNAS paper. It's getting kind of nasty.
posted by mr_roboto at 7:18 PM on August 8, 2012 [3 favorites]


Hey, I just realized this is part of the life cycle for Gremlins. Feed a Mogwai after midnight and it goes into a cocoon, then becomes the eponymous gremlin.
posted by Kevin Street at 7:19 PM on August 8, 2012 [3 favorites]


Also: this entire theory flies in the face of the entirety of epigenetics. Not only would you have to have a bunch of genes from wildly different species mix together and code for a set of proteins that not only wasn't lethal but also formed a coherent animal instead of a hopeless incoherent mess that looked less like a mixture of the two species than like, say, a tumor (which given the number of genes and proteins involved and how easy it is to fuck them up with just a tiny, seemingly-inconsequential alteration here and there is a probability many orders of magnitude smaller than a billion-to-one, definitely in the realm where expontential notation is the only way to even get a glimpse of comprehensibility) you would also have to miraculously change all the little switches and timers and things that determine when genes are expressed (and let me tell you, those switches and timers are complex little buggers that would put Rube Goldberg to shame, and there are thousands upon thousands of them) such that you could get the two ancestor species to manifest as different life-stages in a single organism rather than having all the genes firing off at the wrong time and just having everything go so horribly wrong that you wouldn't even get past the first cell division. I don't think anybody has ever even glimpsed a genetic mechanism that would come anywhere close to even being remotely relevant to enacting that kind of change.

However I am happy to say that hybrid species *do* exist! There are some frogs and insects and more than a few plants (such as wheat, which was originally a hybrid of three different plants and now has *six* copies of each chromosome to show for it) and things that are thought to be the product of two sister-species mating and forming viable offspring (which kind of calls into question whether they were truly separate species at all; species barriers are quite fuzzy much of the time) which then managed somehow to get separated and evolve away from their ancestors to the point that the hybrids are no longer reproductively compatible with their ancestor populations. That is weird and awesome and totally worthy of study. The phenomenon is called hybrid speciation. This, though, is not that. This is not even close to plausible.
posted by Scientist at 7:21 PM on August 8, 2012 [4 favorites]


Can't they do some sort of monitoring between caterpillar and moth to see if the creature is ever actually "dead"?
posted by You Should See the Other Guy at 7:23 PM on August 8, 2012


Can't they do some sort of monitoring between caterpillar and moth to see if the creature is ever actually "dead"?

You can tell it's not dead because it gets out of the cocoon, flies around, and mates.
posted by mr_roboto at 7:24 PM on August 8, 2012 [4 favorites]


13 more things: Hybrid life
New Scientist - 02 September 2009

LOOK at the genome of a sea squirt and you'll get a nasty surprise. Half of its genes have a straightforward evolutionary history. In fairness, so does the other half. Trouble is, the two histories are completely different. It seems that sea squirts do not, as we had thought, sit among the chordates, on the same evolutionary line as humans and other vertebrates. Instead, they are the result of what happens when you fuse an ancient chordate with the ancestor of a sea urchin.
...
The classic case is the starfish Luidia sarsi. It starts out as a small larva with an even smaller starfish inside. Eventually, the starfish moves to the outside of the larva. Then they go their separate ways. What started as one rather odd organism continues and ends life as two.

posted by sebastienbailard at 7:25 PM on August 8, 2012 [7 favorites]


All I can think about right now are the piggies in Speaker for the Dead.
posted by Grandysaur at 7:25 PM on August 8, 2012 [3 favorites]


There is also a problem with the way we think of a cocoon. If we think of it as some external structure , not part of the animal itself this shit is more mindblowing. But if we think of the cocoon as skin, the fact that it contains goop is not so mindblowing. Humans are pretty much goop as well.
posted by Ad hominem at 7:27 PM on August 8, 2012 [8 favorites]


The problem I, a non-biologist, have with this theory is that many insects go through a molting phase - butterflies just seem to be the most dramatic. What about the (hideously terrifying) cicada (warning - there's a time-lapse molt at that link which may give you nightmares)? Is that ALSO two different creatures who mated?
posted by muddgirl at 7:27 PM on August 8, 2012


Lastly (maybe?) if butterflies as we know them (and what about all the other insects that start as larvae and then metamorphose into adults? Ants, anyone? Beetles?) were the result of a hybridization of larva-like and butterfly-like ancestors, where are all their single-stage cousins? Why has nobody ever found a larva-like animal with genitals that doesn't metamorphose and is capable of reproducing on its own? Or an insect that hatches from an egg looking like a fully-formed mini-butterfly? We have lots of counterexamples (hundreds of thousands of counterexamples) of insects that do a similar transformation to butterflies, not to mention a host of genetic information that all speaks to a unitary heritage (hybridization events are very easy to detect genetically and butterfly genetics are extensively studied), but nothing in the modern animal kingdom or in the fossil record which provides a scrap of evidence that this wild conjecture might be true.
posted by Scientist at 7:28 PM on August 8, 2012 [3 favorites]


Yeah, think of the cocoon as just another molt. It's just a very ambitious molt.
posted by mr_roboto at 7:28 PM on August 8, 2012 [4 favorites]


Humans are pretty much goop as well.

I prefer to think of us as intelligent balloons filled with various colored liquids.
posted by Bunny Ultramod at 7:29 PM on August 8, 2012 [3 favorites]


After posting - exactly, Ad hominem. A cicada molts within it's own exoskeleton (and let me tell you, one of the most unpleasant things about living in south Texas are the cicada years like this one - they leave their exoskeletons everywhere). A caterpillar makes a new exoskeleton to molt within.
posted by muddgirl at 7:29 PM on August 8, 2012


(Note that an expression of skepticism is not the same thing as a definitive declaration that this guy is wrong. Just that I'm not convinced and a lot of that article sounds like the beginning of a hypothesis rather than a scientific theory.)
posted by muddgirl at 7:30 PM on August 8, 2012


This kind of event happening is about as likely as you being bitten by a spider and waking up to find that you can shoot webs out of your wrists. To someone with a working knowledge of phylogenetics, it's that level of implausible.
posted by Scientist at 7:33 PM on August 8, 2012 [3 favorites]


Doesn't it have to be a radioactive spider?
posted by St. Alia of the Bunnies at 7:35 PM on August 8, 2012 [1 favorite]


I am the caterpillar. It is my spirit animal. I dance like a caterpillar. I embody unceasing change.

The butterfly is a different creature and has an entirely different symbolism. I am not the butterfly.
posted by Afroblanco at 7:36 PM on August 8, 2012


muddgirl, that is one of the many problems that I, as a biologist, also have with this theory. You are totally spot on that this is a gaping hole in Williamson's theory and would require some supporting evidence that would be really world-shakingly, front-page-of-Nature-guaranteeingly revolutionary in the world of ecology all by itself, nevermind the other problems with Williamson's ideas, of which there are many.
posted by Scientist at 7:46 PM on August 8, 2012


Spiderman is totally unrealistic. Spiders don't shoot webs out of their wrists.
posted by It's Raining Florence Henderson at 7:47 PM on August 8, 2012 [2 favorites]


Also,
So far, however, Williamson's original paper has not been retracted, which is what happens when an idea is so off, or so insupportable that it is no longer scientifically plausible.
I don't think this is true, and I'm surprised that Robert Krulwich would write this! Papers aren't generally retracted for being wrong - lots of incorrect science is published every year. If our standard for correct science is, "It wasn't retracted", then the people who studied the aether so closely are still correct.
posted by muddgirl at 7:48 PM on August 8, 2012 [5 favorites]


Again, that is totally true and Krulwich's statement there was so misleading that I actually can't help but wonder if it wasn't intentionally misleading. Papers are not retracted just for being wrong, otherwise the history of the entire scientific endeavor would be in tatters and we'd constantly be going over old ground because we didn't realize that something had already been tried and found to be incorrect. Papers are retracted for being dangerously misleading or for being the result of ethical violations or other malfeasance. Once something is published it tends to stay published unless there is a damn good reason for retracting it. Merely being wrong isn't enough.
posted by Scientist at 7:54 PM on August 8, 2012 [2 favorites]


I knew a biology grad student here in DC that studied the metamorphosis of moths which are also Lepidoptera. The goop in the cocoon isn't just goop; neurons remain. He'd create these elaborate experiments to see if you could train aversion to a particular smell or taste and see if it was still present in the adult stage. Check it out: Retention of Memory through Metamorphosis: Can a Moth Remember What It Learned As a Caterpillar? Yes, he did say electrical shock.
posted by princelyfox at 8:07 PM on August 8, 2012 [12 favorites]


This is a junk science topic from the same dude from like 3 years ago. Extensively reported on for page views / whatever reason, and just as thoroughly debunked. Not that said debunking matters on a slow day.

That said, there are a lot of actually cool animal configurations out there, that are like, real and stuff.
posted by lazaruslong at 8:14 PM on August 8, 2012


Spiders don't shoot webs out of their wrists.

Instead they wear tiny, adorable wristwatches. They're very punctual.
posted by device55 at 8:18 PM on August 8, 2012 [6 favorites]


It's not good science, but it's a fun idea to chew on for awhile.
posted by Kevin Street at 8:22 PM on August 8, 2012


Remember when that first chicken met that first egg and they just kind of agreed that neither of them came first and they were two different animals?

Good times!
posted by trip and a half at 8:34 PM on August 8, 2012 [4 favorites]


Yeah, I do enjoy ripping apart bunk theories; it's fun to see how many holes you can poke in something, and how quickly. Probably wouldn't be as entertaining for someone more experienced than me though, my PI would probably just roll her eyes and sigh at something like this. Or, actually, she'd say something very polite and noncommittal that simultaneously made it quite clear that she thought I was a bit thick for even bringing it up; she's very British like that.

There *are* really interesting hybrids out there, though! Wheat is one, (I mentioned it above) and it's a fascinating example. Wheat can have up to three sets of chromosomes (six versions of each, as opposed to our two) and each set comes from a different ancestor species. It's thought that the hybridization of modern wheat evolved through human agriculture, as more primitive cereal grains were farmed alongside each other creating new opportunities for cross-pollination. Durum or emmer wheats, themselves already tetraploid (four of each chromosome) hybrids that arose naturally in the wild, hybridized with another wild grass and spontaneously formed the bread wheat that is commonly farmed to this day.

What's interesting (and this actually happens relatively often in plants, and occasionally among some animals too!) is that the chromosome pairs, despite coming from different (albeit very closely related) species, were able to coexist alongside each other and form a new species which was able to reproduce and produce viable, true-breeding offspring. Pretty freaky, for something that we eat every day! It's weird to think of the branches on the tree of life turning back in on themselves like that and forming a new species through recombination.

A hypothetical caterpillar/butterfly hybrid could not have arisen by this method, though. It's really very easy to see when something like this has happened at some point in evolutionary history; when you karyotype a cell (you take all its chromosomes and spread them out so that you can count and identify them) these kind of hybrids are very obvious because each chromosome will have four or six copies instead of the more usual two. That means that if modern lepidopterans were a hybrid of a caterpillar-like animal and a butterfly-like animal and the hybridization had occurred along the lines described above, they should be tetraploid animals. However, they are not -- they are normal diploids, like most animals are. Butterfly genetics are extensively characterized because the long tradition of butterfly classification and the ease of identifying species via wing patterns has long made them exceptional models for evolutionary biology and phylogenetics. In my not-remarkably-large biology department alone there are I think five butterfly specialists among the faculty. If they had undergone this kind of hybridization event in the past, we'd know about it.
posted by Scientist at 8:52 PM on August 8, 2012 [9 favorites]


I prefer to think of us as intelligent balloons filled with various colored liquids.

That's what makes you so fun to step on!

...us. I ment us. Really. Now hoooooold stiiiiiiiillll....
posted by Slap*Happy at 8:58 PM on August 8, 2012


Bernd Heinrich is a genius. Don't any of you understand what this revolutionary theory means for evolution? Heinrich has developed a brand new way to troll the scientific community, with only minimal effort! This insightful development unlocks brand new doors for the troll community, and the techniques and procedures we learn from studying his work may one day evolve internet trolling to levels undreamed off by today's primitive standards.
posted by wolfdreams01 at 9:34 PM on August 8, 2012 [1 favorite]


You can tell it's not dead because it gets out of the cocoon, flies around, and mates.

But while it's in the cocoon it is totally undifferentiated goo -- all of its organs and structures and even cells just dissolve. That's incredibly weird -- and not even remotely like any sense in which humans are "also bags of goo", or even other insects in the pupal stage.

I'm not buying this guy's theory, but what he's saying is really just semantics. The stuff inside the cocoon is not a living creature in the sense we normally mean. It's not anything; it's just juice. I don't think his theory is all that interesting, really; the truth is far stranger than the scientist.

The other insect that freaks me out is phylloxera, the bug that destroyed Europe's vineyards. It has two lifecycles that are unrelated to each other, each of which mates in a completely different way. I'm sure there are many more that are just as strange.
posted by Fnarf at 9:47 PM on August 8, 2012 [2 favorites]


Or, you know, what Scientist said.

Am I the only one who feels like they're in a Half Baked mini-skit every time you want to compliment the guy?
posted by Dark Messiah at 9:50 PM on August 8, 2012


I'm not buying this guy's theory, but what he's saying is really just semantics. The stuff inside the cocoon is not a living creature in the sense we normally mean. It's not anything; it's just juice.

This is nonsense. There's a pretty well-document developmental process going on in there. See this gorgeous imaging work, for instance.
posted by mr_roboto at 10:06 PM on August 8, 2012 [2 favorites]


"But while it's in the cocoon it is totally undifferentiated goo"

Not total goo. It's still got DNA in there, along with the epigenetic factors Scientist mentioned, and if princelyfox's friend is right there's brain material carried over from caterpillar to butterfly. Basically the minimum stuff you'd need to convert the goo into a new form.
posted by Kevin Street at 10:06 PM on August 8, 2012


well-documented
posted by mr_roboto at 10:06 PM on August 8, 2012


It's still got DNA in there, along with the epigenetic factors Scientist mentioned

And all of the cells that make up the imaginal discs. These cells are present in the larvae, present in the pupae, and develop in a process analogous to embryonic development.
posted by mr_roboto at 10:09 PM on August 8, 2012


Apologies, I didn't see your comment before I posted. So the larvae already contains cells that will develop it into a butterfly.
posted by Kevin Street at 10:14 PM on August 8, 2012


Jah, not just goo. There are living cells in there, they're just not as highly differentiated as we're used to seeing them. Living cells in an extracellular matrix, developing into butterflies. It's not just juice, it's definitely still alive.
posted by Scientist at 10:15 PM on August 8, 2012


Yup, the larva of necessity contains all the equipment needed for metamorphosis. Of course, some of that equipment exists to build the equipment to build the equipment to, well, you get the idea, but it's all there at the DNA level at the very least. Not that this is what invalidates Williamson's theory; the hybridization theory would of course accommodate this by stating that one of the amazing things about the hybridization is that the caterpillar phase was given instructions from the butterfly phase to build the butterfly. Which if true would indeed be pretty amazing.

It's not true, though. There are lots and lots of reasons why it's not true, but that's not one of them. Caterpillars have everything they need to transform into butterflies, by definition. Not even Williamson is arguing with that, although his hypothetical caterpillar-like parent species would of course have lacked the ability to transform.
posted by Scientist at 10:19 PM on August 8, 2012


I'm sorry, I'm not a scientist and I can't make heads or tails of anything in that article. I get that DNA is still there, but I was under the impression the cells all completely dissolved. I'm sorry if I'm stupid and wrong.

It would be awesome if there was something like a Wikipedia article that was written in plain English, explaining what all the jargon means.

It's still an incredibly freaky series of events. I think it's outside the bounds of what we ordinarily think of as "alive", but it's obvious that life is far more varied than what anybody ordinarily thinks.
posted by Fnarf at 10:19 PM on August 8, 2012


I can't make heads or tails of anything in that article.

Holy shit, yeah, the first sentence of that abstract, yeah.

"Drosophila imaginal discs are monolayered epithelial invaginations that grow during larval stages and evert at metamorphosis to assemble the adult exoskeleton."

That's rough stuff. Sorry.
posted by mr_roboto at 10:27 PM on August 8, 2012


It gets better: "JNK Signaling Is Active in Peripodial and Stalk Cells prior to and at Eversion(A) puckered expression in wing imaginal discs before eversion. puc is expressed in the stalk of the disc throughout the third larval stage and in an increasing number of PE cells as larva ages."

Ooh, sexy.

I found a useful English-language bit over on Ask Metafilter.
posted by Fnarf at 10:32 PM on August 8, 2012


No big. princelyfox mentioned upthread that there are still neurons in the goop, but the comment was easy to miss. Super interesting comment though. This article has a bit of information on what actually is inside the chrysalis when a caterpillar is metamorphosing into a butterfly. Basically the caterpillar's body self-digests to the point where it's mostly just some stem cells (the imaginal discs) hanging out in a nice rich cell growth medium. It does dissolve, almost entirely, but not completely. Those stem cells then essentially start growing and redifferentiating into a butterfly. It's pretty drastic stuff, you couldn't reduce the body much more without killing it, it goes almost all the way back to the fertilized egg. Still though, there's continuity there. It's not dead, and it's not just floating DNA. It's definitely still living cells, just not as many of them and they're not as highly differentiated as we would expect. It's still quite the biological miracle.

While I'm at it, another animal that I can think of is capable of de-differentiating its cells: salamanders. Salamanders are famous for the fact that you can cut bits off of them and those bits will grow back good as new. They are much better at this than just about any other similarly-complex animal, certainly they're champions among land vertebrates. It was originally thought that they did their trick using stem cells that were stored in the tissue for later use in regrowing limbs and such, but it turns out that that's not the case. When you wound a salamander, the cells around the wound will respond by reverting to a less-differentiated state; that is, they'll stop being skin and muscle and bone and whatever and turn back into stem cells, at which point they proceed to grow whatever part of the salamander is needed.

How this happens we still have only a hazy idea. The whole mechanism for how cells know where in the body they are and what kind of tissue they are supposed to become is super complicated and we really are lacking a lot of information in that area albeit it's certainly an active area of research. It's a pretty good trick though, and it's similar in some ways (not all that similar overall, but in some ways) to what butterflies do when they're changing from larvae to adult.
posted by Scientist at 10:32 PM on August 8, 2012 [4 favorites]


"Drosophila imaginal discs are monolayered epithelial invaginations that grow during larval stages and evert at metamorphosis to assemble the adult exoskeleton."

The imaginal discs on the fly Drosophila melanogaster are a single layer of barrier cells (like skin cells, or the coating around your organs) that form a groove on the body of the larva which grows inwards during the larval phase of the fly and then turns inside-out when metamorphosis occurs and grows into the adult exoskeleton.

"JNK Signaling Is Active in Peripodial and Stalk Cells prior to and at Eversion(A) puckered expression in wing imaginal discs before eversion. puc is expressed in the stalk of the disc throughout the third larval stage and in an increasing number of PE cells as larva ages."

This one is harder. I could figure that out but it'd take a while. Some signaling pathway is active in some set of cells just before the larva transforms into the adult, and there's some artificially-induced mutation that starts to make itself shown at the third larval stage and which becomes more pronounced over time after that.
posted by Scientist at 10:40 PM on August 8, 2012 [1 favorite]


I always get a kick out of how Hart and Grosberg titled their critique. So blunt and to the point:

Williamson 2009:
Caterpillars evolved from onychophorans by hybridogenesis.
Hart and Grosberg 2009:
Caterpillars did not evolve from onychophorans by hybridogenesis.
posted by bergeycm at 10:43 PM on August 8, 2012 [7 favorites]


Yeah, when you see a rebuttal paper with a title that blunt, you know someone's pissed. If they were trying to be at all respectful they would have titled it something like "Evidence in favor of a traditional interpretation of lepidopteran evolutionary history". The title that they chose is the closest thing you're going to see in a scientific journal to "Fuck you, you're wrong."
posted by Scientist at 10:52 PM on August 8, 2012 [10 favorites]


Anyone have knowledgeable comment about the New Scientist article about sea squirts as hybrids?

I see that Williamson has been active in that area too, claiming to have fertilized tunicate eggs with sea urchin sperm and vice versa. My confidence is not raised, but I'd like to hear more about what the article's saying about the genome, which I haven't found in websearching.
posted by away for regrooving at 10:54 PM on August 8, 2012


I would be much more apt to believe that sea squirts were a symbiotic relationship between an echinoderm and a chordate (though I'd be very surprised and would have to see some pretty incontrovertible evidence) than that they were a cross-phylum hybrid. It would be like crossing a fly with a mouse and getting some kind of flying mouse. I haven't looked into it in detail but it looks pretty stupid on the face of it.
posted by Scientist at 11:11 PM on August 8, 2012


The starfish thing seems to be legit though. Currently looking into getting a journal article about this. Almost FPP-worthy of its own right, but most of the info will be locked behind a paywall. Sigh.
posted by Zarkonnen at 11:38 PM on August 8, 2012


It would be like crossing a fly with a mouse and getting some kind of flying mouse.

Ridiculous. Everybody knows that the offspring of a fly and a mouse is a cheese maggot.
posted by It's Raining Florence Henderson at 11:45 PM on August 8, 2012 [1 favorite]


Everybody knows that the offspring of a fly and a mouse is a cheese maggot

Which then dies, and from its dead juices arises a flying mouse. DUH
posted by Auden at 1:24 AM on August 9, 2012


It's not science until Heinrich performs an experiment to verify his hypothesis that moths and caterpillars are two different animals altogether.

Yes, but instead of calling it an experiment he should call it the "Heinrich maneuver."
Which will ultimately draw the ire and criticism of the scientific community, which will be quick to point out that a "maneuver" is an entirely different animal altogether.
posted by sour cream at 1:42 AM on August 9, 2012


/learns something new about what happens in cocoons
/day no longer a complete write-off
posted by obiwanwasabi at 2:03 AM on August 9, 2012


Butterfly has 2-phenotype sequential 2-species LIFESQUARE within single lifespan.

2-species lifespan proves 1 LIFE 1 SPECIES is TAUGHT EVIL.

IGNORANCE OF LIFESQUARE2 SIMPLE MATH IS RETARDATION AND EVIL EDUCATION DAMNATION
posted by A Thousand Baited Hooks at 2:28 AM on August 9, 2012 [5 favorites]


I am a big fan of Bernd Heinrich. He is a very astute scientist and an engaging and enlightening author. I will read his book.
posted by Jode at 4:02 AM on August 9, 2012


It would be like crossing a fly with a mouse and getting some kind of flying mouse.

Wait, so that isn't where bats come from?
posted by logopetria at 5:36 AM on August 9, 2012


Basically the caterpillar's body self-digests to the point where it's mostly just some stem cells (the imaginal discs) hanging out in a nice rich cell growth medium. It does dissolve, almost entirely, but not completely. Those stem cells then essentially start growing and redifferentiating into a butterfly. It's pretty drastic stuff, you couldn't reduce the body much more without killing it, it goes almost all the way back to the fertilized egg.

Holy shit, they're like little Time Lords.
posted by EmpressCallipygos at 8:17 AM on August 9, 2012 [1 favorite]


Yes. Mothra and Rhodan
posted by stormpooper at 11:39 AM on August 9, 2012


Some people don't really understand how scientific theories work.
posted by Mental Wimp at 11:48 AM on August 9, 2012


How this happens we still have only a hazy idea. The whole mechanism for how cells know where in the body they are and what kind of tissue they are supposed to become is super complicated and we really are lacking a lot of information in that area albeit it's certainly an active area of research.

Hurry up and find this out, okay, scientists (not talking to you, necessarily, Scientist).
posted by Mental Wimp at 12:01 PM on August 9, 2012


How funny.

I think this is very possibly true, but I can't believe they think this could have arisen from two unrelated species randomly mating, because that is such a relatively rare event.

But there is something that happens many orders of magnitude more often and actually has a very strong resemblance in its external form to the process of a caterpillar going off, pupating and then emerging later as a butterfly.

I refer, of course, to the process of a parasitic wasp attacking a caterpillar, laying its eggs in it, then after a period of time the eggs hatch, the wasp larvae eat the caterpillar from the inside, emerge and pupate themselves, and then a new generation of wasps is born.

All that would have been necessary for an ur-butterfly to be created in this process is for a single wasp parasitizing a caterpillar-like ancestor (which ancestor would have given rise only to more caterpillars) to have one of of its eggs pick up enough genes a from the caterpillar-like host for that egg to develop into a caterpillar-like larva rather than a wasp-like larva, eat plants like a caterpillar, then pupate and develop into a flying form in which the wasp genes dominate.

And astoundingly enough, there is a vector on the scene which has already shown itself to be fully capable of transmitting genetic material from the host into the wasp genome: the viruses and virus-like particles which coat the eggs of parasitic wasps when they inject them into the hosts and have the effect of disabling the host's immune response to the eggs:
...In most cases mentioned above, the viruses have limited or no effect on the wasp but are pathogenic to the parasitoids’ hosts. Therefore, it is quite tempting to speculate that they originated from lepidopteran pathogens rather than hymenopteran. The isolated viruses are all capable of replicating in host (lepidopteran) cells in which they have pathologic effects, although they are transmitted by the apparently unaffected wasps. During the course of evolution, these viruses might have been “domesticated” by certain wasps; in some cases, viral genetic material may have become integrated into the wasp genomes and tissue-specific replication mechanisms evolved that are regulated by the wasps...

...Bracoviruses and ichnoviruses, in which there is integration of the genome into wasp chromosomes, with single and multiple DNA molecules incorporated into particles (Albrecht et al., 1994; Stoltz et al., 1981), may represent the next stage of an evolutionary process (operating independently within the two wasp groups) towards complete dependence of virus functions on the wasp. ...
Until I saw this post last night, I thought this was the mechanism by which advocates of the hybridization theory thought it had taken place.

It occurred to me right after I read the PDF about the viruses that I linked above because it was linked in a wonderful comment by edd back at the end of 2007.

I see from searching for wasp within the thread that empath has had the same idea.

Good thinking, empath!
posted by jamjam at 12:25 PM on August 9, 2012 [2 favorites]


My link about wasps parasitizing caterpillars didn't come throgh for some reason.
posted by jamjam at 12:29 PM on August 9, 2012


So jamjam, how would that wasp egg have picked up those caterpillar genes? (Enough genes to code for an entire caterpillar, in fact?) How would those genes have been able to integrate themselves into the wasp's chromosomes? How would they have arranged themselves such that rather than just creating a hopeless mess (which is what you'd normally get if you tried to make an order-level hybrid -- wasps are order hymenoptera and butterflies are order lepidoptera, a similar level of relatedness as humans and mice) they created a viable hybrid animal? How would they not only create a viable hybrid animal, but instead create a new animal which was *both* animals but in two stages?

Also, how do you explain the fact that there are no other species of self-reproducing caterpillars out there? If this only happened once there'd be no reason to expect that it would have caused an entire class of caterpillar-like organisms to go extinct.

Furthermore, what about all the other non-parasitoid hymenopterans such as sawflies, bees, ants, and other wasps which undergo a larva -> pupa -> adult insect life cycle similar to both existing parasitoid wasps and to butterflies? And what about the other eleven orders of insects comprising the superorder holometabola which all undergo complete metamorphosis similar to butterflies? Beetles all do this sort of metamorphosis, and they comprise literally a quarter of all known or predicted multicellular species, some 450,000 species just within that order alone.

There are deep, dealbreaking problems with Williamson's theory at every level from the molecular to the evolutionary to the phylogenetic. It's the sort of thing that in order to be true would require the overturn of pretty much all the major theories in Biology -- cell theory, the theory of natural selection, and the central dogma of molecular biology would all have to be spectacularly wrong for the proposed event to occur. Not only is there not the kind of aliens-have-landed-and-they're-on-the-evening-news extraordinary evidence that would be required to support this kind of multiple-revolution, there's actually not much of any evidence at all. All we have here is kind of a fluffy pseudoscientific story cooked up by a crank who's embarrassing his department by continuing to push this so hard.
posted by Scientist at 7:35 PM on August 9, 2012 [1 favorite]


I'm no entomologician, but as I understand it the chance of this happening is considerably smaller than the likelihood that you could cram a Windows disc and a MacOS disc into a CD-ROM drive and boot up into an operating system that had features of both.
posted by A Thousand Baited Hooks at 9:56 PM on August 9, 2012


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