Cockroaches evolve aversion to glucose

Posted 24 May 2013 by Matt Young

Not stated is whether they manage to lose weight, nor whether they still get cavities or develop diabetes. But a recent article in Science shows that cockroaches evolved an aversion to glucose after glucose was used for a number of years as a poisoned bait. That is, the cockroaches developed an aversion to the bait rather than a resistance to the poison. The Science article is kind of written in Greek

In response to the anthropogenic assault of toxic baits, populations of the German cockroach have rapidly evolved an adaptive behavioral aversion to glucose (a phagostimulant component of baits).

but The New York Times has a nice summary and notes, almost as a throw-away, that the result might have application to diseases, such as malaria, that are spread by mosquitoes. Memo to potential trolls: Yes, yes, we know—they are still cockroaches!!

70 Comments

Mike Elzinga · 24 May 2013

Memo to potential trolls: Yes, yes, we know—they are still cockroaches!!

True; but they no longer have any sugar daddies.

Keelyn · 24 May 2013

Mike Elzinga said:
Memo to potential trolls: Yes, yes, we know—they are still cockroaches!!
True; but they no longer have any sugar daddies.

LOL! I guess somebody had to do it.

DS · 24 May 2013

"Memo to potential trolls: Yes, yes, we know—they are still cockroaches!!"

That's a bit harsh don't you think?

Henry J · 24 May 2013

But they're still insects! hexapods! arthropods! metazoa! eukaryotes!

Also any categories that should be between those.

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad · 24 May 2013

Probably evolved an aversion to shoes, too.

The cockroaches I've seen play dead after a good clogging.

Glen Davidson

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad · 24 May 2013

If cockroaches evolved, why is there still the Discovery Institute?

Got you, monkey-pants evilutionists!

Glen Davidson

Doc Bill · 24 May 2013

Memo to self: stop sending candy to the Disco Tute. They won't eat it.

Mark Sturtevant · 24 May 2013

So, putting insecticide on our skin could select for mosquitoes to have an aversion for landing on us? Is that the dumb possible application?

harold · 24 May 2013

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad said: If cockroaches evolved, why is there still the Discovery Institute? Got you, monkey-pants evilutionists! Glen Davidson

They didn't evolve from weasels.

Mark Sturtevant · 24 May 2013

OK, according to the NY Times article efforts to control mosquitoes that can carry malaria was stymied by selection for mosquitoes that do not rest on walls inside of homes, where pesticides are generally sprayed. The roaches can be another example of selection that just happens to avoid a pesticide. In this case it seems to be selection for roaches that detect glucose as a bitter substance. Interesting.

diogeneslamp0 · 24 May 2013

But they're still bilaterians!

Sorry. Couldn't resist.

glipsnort · 24 May 2013

DS said: "Memo to potential trolls: Yes, yes, we know—they are still cockroaches!!" That's a bit harsh don't you think?

Why?

DS · 24 May 2013

glipsnort said:
DS said: "Memo to potential trolls: Yes, yes, we know—they are still cockroaches!!" That's a bit harsh don't you think?
Why?

Well the regular trolls might deserve it, but even the potential trolls?

EvoDevo · 25 May 2013

They're still eumetazoans.

Ray Martinez · 25 May 2013

"In response to the anthropogenic assault of toxic baits, populations of the German cockroach have rapidly evolved an adaptive behavioral aversion to glucose (a phagostimulant component of baits)."

Evolution (unintelligence) is assumed; the actual evidence could rightly be interpreted as being caused by invisible Intelligence. In fact, it is highly illogical to say an unguided and unintelligent process was responsible.

phhht · 25 May 2013

Ray Martinez said:
"In response to the anthropogenic assault of toxic baits, populations of the German cockroach have rapidly evolved an adaptive behavioral aversion to glucose (a phagostimulant component of baits)."
Evolution (unintelligence) is assumed; the actual evidence could rightly be interpreted as being caused by invisible Intelligence. In fact, it is highly illogical to say an unguided and unintelligent process was responsible.

Why should anyone interpret the evidence that way? Just because you say so?

Matt Young · 25 May 2013

Further comments by the Martinez troll will be sent to the bathroom wall. Please do not feed it (the troll, that is).

DS · 25 May 2013

Martinez is still a cockroach, even on the bathroom wall.

Matt Young · 25 May 2013

Forgive me, but cockroaches have shown a capacity to learn. Trolls do not.

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad · 25 May 2013

Ray learns.

Mainly misrepresentation, but it's still a very minimal sort of learning.

Learning science, proper inference, etc., never. Heaven forbid, or at least his version of heaven forbids it.

Glen Davidson

DS · 25 May 2013

Matt Young said: Forgive me, but cockroaches have shown a capacity to learn. Trolls do not.

Agreed. Maybe we should try the glucose test on Ray.

John_S · 25 May 2013

Ray Martinez said: In fact, it is highly illogical to say an unguided and unintelligent process was responsible.

It will become illogical when you show us some reasonable evidence for the existence and actions of the intelligent guide that explains the process better than the natural explanation we already have.

Sinjari · 25 May 2013

Ray Martinez said: it is highly illogical to say an unguided and unintelligent process was responsible.

Can anyone tell me why an intelligent, guiding agent would even care about the welfare of German cockroaches?

DS · 26 May 2013

Sinjari said:
Ray Martinez said: it is highly illogical to say an unguided and unintelligent process was responsible.
Can anyone tell me why an intelligent, guiding agent would even care about the welfare of German cockroaches?

Don't be silly man, it's the cockroaches themselves. They were intelligent enough to figure out that they were being poisoned and that the glucose was being used as bait. They were then intelligent enough to sequence their own genome and determine the genes responsible for taste. They then genetically engineered themselves to taste bitter instead of sweet and presto, they now had an aversion to glucose. So you see, they will now avoid glucose, even though it is rarely associated with poison and is usually a good source of energy. What they were apparently not intelligent enough to do was to just avoid the poison! What a shame.

harold · 26 May 2013

DS said:
Sinjari said:
Ray Martinez said: it is highly illogical to say an unguided and unintelligent process was responsible.
Can anyone tell me why an intelligent, guiding agent would even care about the welfare of German cockroaches?
Don't be silly man, it's the cockroaches themselves. They were intelligent enough to figure out that they were being poisoned and that the glucose was being used as bait. They were then intelligent enough to sequence their own genome and determine the genes responsible for taste. They then genetically engineered themselves to taste bitter instead of sweet and presto, they now had an aversion to glucose. So you see, they will now avoid glucose, even though it is rarely associated with poison and is usually a good source of energy. What they were apparently not intelligent enough to do was to just avoid the poison! What a shame.

That's the Lamarckist explanation (also sometimes invoked by badly confused creationists in their effort to "say anything to contradict evolution"). For a definitive ID explanation we have to go to a real expert, like Michael Behe. Behe has made it clear that the Designer favors malaria parasites over humans. He has also noted that the bacterial flagellum, which increases the fitness of some pathogens, is magically designed by the Designer. Other authorities repeatedly assert that a deity rumored to be the same as Behe's designer, wink, wink, is directly responsible for massive natural disasters. Cockroaches are disgusting but massively less dangerous than malaria. They can cause a nasty allergy, and they are good "canary in a coal mine" indicators or unsanitary conditions that may harbor more dangerous threats, but in themselves, they aren't especially threatening to human life. So I would say, Sinjari, according to ID/creationists, favoring cockroaches is the least of it. So I would say, why

harold · 26 May 2013

Too many typos, point still stands.

DS · 26 May 2013

Perhaps I wasn't clear. My point was that what was observed was probably the least intelligent thing that you could do in response to poison. Whether cockroach or god, if you really did have any sort of actual "intelligence" you could certainly have come up with a better solution. Why not just avoid the poison, or make yourself immune to it, or find a way to metabolize it and get energy from it, or just eat the glucose and leave the poison, or use the poison to poison those who were trying to poison you, or avoid glucose without having it taste bitter, or choose one of a thousand simpler and better solutions?

On the other hand, what is observed is exactly the sort of thing that you would expect from random mutation and natural selection. And since that hypothesis explains all of the evidence, there is no need to invent any unseen forces and unlikely mechanisms for which there is absolutely no evidence. So Ray has once again been decapitated by Occum's razor. That's why he never provides any explanations, he just tries to ridicule evolution. If he ever did come right out an say what the fudge he's talking about, everyone could see immediately that he was full of excrement.

SensuousCurmudgeon · 26 May 2013

DS said: On the other hand, what is observed is exactly the sort of thing that you would expect from random mutation and natural selection. And since that hypothesis explains all of the evidence, there is no need to invent any unseen forces and unlikely mechanisms for which there is absolutely no evidence.

Ah, but it all depends on your faith-based presuppositions. You are assuming -- without evidence! -- that we don't live in a world ruled by invisible entities that miraculously guide us. [End creationism mode]

harold · 26 May 2013

DS said: Perhaps I wasn't clear. My point was that what was observed was probably the least intelligent thing that you could do in response to poison. Whether cockroach or god, if you really did have any sort of actual "intelligence" you could certainly have come up with a better solution. Why not just avoid the poison, or make yourself immune to it, or find a way to metabolize it and get energy from it, or just eat the glucose and leave the poison, or use the poison to poison those who were trying to poison you, or avoid glucose without having it taste bitter, or choose one of a thousand simpler and better solutions? On the other hand, what is observed is exactly the sort of thing that you would expect from random mutation and natural selection. And since that hypothesis explains all of the evidence, there is no need to invent any unseen forces and unlikely mechanisms for which there is absolutely no evidence. So Ray has once again been decapitated by Occum's razor. That's why he never provides any explanations, he just tries to ridicule evolution. If he ever did come right out an say what the fudge he's talking about, everyone could see immediately that he was full of excrement.

Your point is clear and needless to say I agree with all of that. I'm making what may be a subtle point. Lamarckism is wrong but still a lot less wrong than ID/creationism. Under Lamarckism, which seems silly to those who have studied biology but is a common intuitive assumption, the cockroaches mysteriously "know" that they "need" to avoid glucose and somehow mutate their own genomes. Under ID/creationism, the cockroaches don't do it themselves. ~~The post-modern right wing fundamentalist God~~ "The designer" does everything. Which generates a whole new set of problems.

DS · 26 May 2013

Then we are in complete agreement, which make you wise beyond my years. But why would anyone assume that cockroaches were intelligent in order to promote a religious agenda? Perhaps Ray is just going senile.

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad · 26 May 2013

DS said: Then we are in complete agreement, which make you wise beyond my years. But why would anyone assume that cockroaches were intelligent in order to promote a religious agenda? Perhaps Ray is just going senile.

I can't imagine how there could be a more difficult diagnosis than that one. Glen Davidson

Just Bob · 26 May 2013

Going senile?

Scott F · 26 May 2013

DS said: So Ray has once again been decapitated by Occum's razor. That's why he never provides any explanations, he just tries to ridicule evolution. If he ever did come right out an say what the fudge he's talking about, everyone could see immediately that he was full of excrement.

Actually, Ray has come right out and said what he's talking about in previous conversations on the BW. You had it right the first time, and it isn't Lamarckism at all. As I understand Lamarckism, there's no "intention" involved. An individual animal stretches its neck, its neck gets longer, or it gets better at what it does, and this change is then passed onto the next generation. As I understand it, Ray's position isn't a "religious" one, or at least it's not your "classic" garden variety Bible-based Creationism. Ray's has explicitly said that all living things, explicitly including bacteria, are intelligent enough to intentionally alter their genome to better fit their environment. That is, they explicitly intentionally cause mutations in their genome to produce desired effects in their phenotype. This "intelligence" isn't a physical construct, but resides in some alternate plane, or reality, or something. Further, this "intelligence" is individual. When Ray talks about intelligence guiding mutation, he's not talking about a single all-powerful God directing all mutations. He's talking about the separate "intelligence" of each separate organism doing the intelligent guiding. Our problem is that he tends to use the same language that Intelligent Design Creationists use, like those of the Discovery Institute, so people often mistake Ray for one of "Them". But when Ray uses them, those words mean very different things, and can lead to even more confusion. For example, if one were to ask Ray, "Why would God care about making better cockroaches?" that would only lead to a confusing exchange. Ray isn't claiming that God modified the cockroach. He's claiming that the "intelligent" cockroach recognized the problem in the environment, and then modified itself. The advantage to this (from Ray's point of view) is that the "intelligence" of each creature isn't "perfect". It isn't the omniscient and omnipotent God of the Bible, and so less-than-optimal solutions are allowed, or even preferred. So with small "i" "intelligence", the question of, "Why choose this particularly stupid mutation?", the easy answer is, "Well, what do you expect from the intelligence of a cockroach?" This "explains" (or makes excuses for) the "bad" design that we see in the world around us. It's just a sub-optimal solution that was "created" locally, without the broader perspective of a "better" intelligence. It sounds weird, even weirder than your bible-thumping YEC, but it seems to be what he believes. It's more like polytheistic evolution, or perhaps pantheistic evolution, or something unique. If you ever get to arguing with him, don't get sucked in by what you think he meant.

Henry J · 26 May 2013

Sinjari, 5/25/13 9:44 PM Ray Martinez said: it is highly illogical to say an unguided and unintelligent process was responsible.

Can anyone tell me why an intelligent, guiding agent would even care about the welfare of German cockroaches? BECAUSE, that's why!!!!!

Mike Elzinga · 26 May 2013

This cockroach has become a major pest in Houston and New Orleans, and is second only to the German cockroach in homes in southwest Georgia.

So, prior to this evolutionary change, there could very well have been a cockroach called “Sweet Georgia Brown.”

DS · 26 May 2013

Unfortunately, Ray has also explicitly stated that he refuses to accept evolution due to his religious beliefs. He even refuses to examine evidence, presumably because it challenges his faith, which is apparently too weak to withstand any encounter with reality. I don't know how he can have faith in the intelligence of cockroaches, but somehow he seems to have gotten the entire thing all mixed up in his mind. How sad.

Henry J · 26 May 2013

He’s claiming that the “intelligent” cockroach recognized the problem in the environment, and then modified itself.

Do Ray and Gary know each other?

harold · 27 May 2013

You had it right the first time, and it isn’t Lamarckism at all. As I understand Lamarckism, there’s no “intention” involved. An individual animal stretches its neck, its neck gets longer, or it gets better at what it does, and this change is then passed onto the next generation. As I understand it, Ray’s position isn’t a “religious” one, or at least it’s not your “classic” garden variety Bible-based Creationism. Ray’s has explicitly said that all living things, explicitly including bacteria, are intelligent enough to intentionally alter their genome to better fit their environment. That is, they explicitly intentionally cause mutations in their genome to produce desired effects in their phenotype. This “intelligence” isn’t a physical construct, but resides in some alternate plane, or reality, or something. Further, this “intelligence” is individual. When Ray talks about intelligence guiding mutation, he’s not talking about a single all-powerful God directing all mutations. He’s talking about the separate “intelligence” of each separate organism doing the intelligent guiding.

I'm not a big fan of semantic debates, but Ray's system is a form of Lamarckism. I realize that words change in meaning. "Lamarckism" isn't a very precise word, because Lamarck didn't really push the idea. Still, I think it has a clear enough meaning. The idea that spontaneous germline mutations routinely occur in a targeted way, which directly adapts to the environment without a role for subsequent selection, is Lamarckism. Ray's version is part of a religious scheme of evolution denial, but Lamarckism broadly defined is wrong only because it doesn't fit the evidence. All current data suggests that germline mutations are largely independent of human-perceived future "needs" of an organism, which is the opposite of what Lamarckism predicts. If someone thinks that giraffes got longer necks because giraffe "need" or "desire", whether expressed by giraffe conscious wishes, or merely by mysterious feedback from neck tendons onto germline nucleic acids, directly provoked a targeted mutation, that person believes in Lamarckism. Lamarckism raises two major problems. One, how does the giraffe's body know to place a perfectly targeted mutation into the germline DNA, and also, I might add, does it put into one sperm or ovum which it knows in advance somehow will become a zygote, or does it simultaneously put it in all gametes? And two, if this is the mechanism of mutation, why are there ever negative mutations? Still, Lamarckism is a common, intuitive idea. It's wrong because it doesn't fit the evidence, not because it's inherently stupid. It's usually what people think happens BEFORE they learn how genetics actually works. Very, very few creationists are Lamarckists. More often, and this is common, creationist attacks on straw man versions of "the theory of evolution" are actually attacks on Lamarckism. Lamarckism doesn't reference any "need" for a deity. However, Ray and a few other rare creationists, typically ones who are banned from creationist sites and so on, do incorporate Lamarckism into their individual ideas.

Marilyn · 27 May 2013

The sting of a jellyfish is lethal by the poison going straight to heart but studies are being carried out to find if this can be used to find a medium to send the right medication quicker to the heat. So the cockroach chooses not to eat the glucose but will still eat the poison the lesson is its still experimenting its sifting through the problem would be interesting to see if it rejects another component in the poison. It is possible to eat cockroaches if cooked at a very high temperature I don't think I would definitely not one bread out of captivity but I wonder how this will eventually affect the taste of the cockroach with it not eating glucose perhaps would not be such a “Sweet Georgia Brown”

Marilyn · 27 May 2013

The cockroaches progression would be a matter of choice rather than chance.

DS · 27 May 2013

Marilyn said: The cockroaches progression would be a matter of choice rather than chance.

Sorry Marilyn, wrong once again. It was a random mutation which affected perception and thus behavior. The cockroaches didn't choose the behavior, it was selected on until the allele frequency increased. It's not a "progression" or a "problem" for them and they are not "experimenting", except in the most distorted and anthropomorphic sense. Are you married to Robert Byers by any chance? If not, I would like to introduce you to him. I think you two would get alone famously, even if no one else understood a word.

harold · 27 May 2013

DS said:
Marilyn said: The cockroaches progression would be a matter of choice rather than chance.
Sorry Marilyn, wrong once again. It was a random mutation which affected perception and thus behavior. The cockroaches didn't choose the behavior, it was selected on until the allele frequency increased. It's not a "progression" or a "problem" for them and they are not "experimenting", except in the most distorted and anthropomorphic sense. Are you married to Robert Byers by any chance? If not, I would like to introduce you to him. I think you two would get alone famously, even if no one else understood a word.

I forgot to mention that Marilyn is another very committed Lamarckist. Marilyn is religious, but there are undoubtedly atheists out there who don't know much about biology, and also unwittingly assume Lamarckism. It's extremely common for people to project the human perception of conscious planning onto all of nature. I don't remember the day when I realized "Oh, wait, the mutations don't have to be planned - they're acted on by selection later". It was probably during a molecular biology course. Darwin got it without even understanding genetics, but for the rest of us, understanding genetics makes it a lot easier to get. Standard issue Fox News-parroting "on message" creationists were selected against at PT a long time ago. They learned that PT is a place where there arguments are met with responses that make them uncomfortable, and they were discouraged by Dover. IBIG and FL more or less parrot the approved "up to date authoritarian follower" version of anti-science, but both have personal characteristics that may make them less than welcome at standard creationist sites. The rest of the "creationist regulars" here mainly adhere to their own idiosyncratic systems. The typical contemporary "movement" creationist would not visit a site where material that dissents from creationism (or the related right wing authoritarian ideological stances) is permitted. Once in a while they stumble here, and express shock that such a thing could exist. Pre-Dover the trend was to do battle with the "evolutionists" but these days, after setbacks, the trend is to isolate themselves from reality. The ones we see here are, whether disturbingly, admirably, or both, the ones who can tolerate constant exposure to rational correction without being the least bit bothered or changed.

harold · 27 May 2013

Designer almighty, used preview and STILL made a "there/their" error.

Matt Young · 27 May 2013

As I understand Lamarckism, there’s no “intention” involved. An individual animal stretches its neck, its neck gets longer, or it gets better at what it does, and this change is then passed onto the next generation.

No. Lamarck was smarter than that - spaniels are not born with their tails bobbed nor Jewish boys circumcised. Intentionality was involved: The giraffe had to "will" its neck to get longer; the blacksmith had to will his muscles to be bigger. Lamarck's view was not irrational, and it was completely consistent with the view that some sort of "life force" propelled living organisms.

apokryltaros · 27 May 2013

Marilyn said: The cockroaches progression would be a matter of choice rather than chance.

No. It is not a matter of choice on the cockroach's part. Those cockroaches that have a genetic predisposition to crave a glucose-rich diet would die from eating glucose-rich poisoned bait, and have their own sub-population reduced further, while those cockroaches that do not have a genetic predisposition to crave a glucose-rich diet would have their own sub-population increase because fewer members were dying from eating glucose-rich poisoned bait. Or are you saying that cockroaches are choosing to commit suicide or that cockroaches are magically smart enough to go on diets because humans are giving them poisoned food?

TomS · 27 May 2013

harold said: Lamarckism raises two major problems. One, how does the giraffe's body know to place a perfectly targeted mutation into the germline DNA, and also, I might add, does it put into one sperm or ovum which it knows in advance somehow will become a zygote, or does it simultaneously put it in all gametes? And two, if this is the mechanism of mutation, why are there ever negative mutations? Still, Lamarckism is a common, intuitive idea. It's wrong because it doesn't fit the evidence, not because it's inherently stupid. It's usually what people think happens BEFORE they learn how genetics actually works.

Once again, I find much to agree with in harold's post. I'd like to add one remark of Darwin, near the end of the chapter on "Instinct" in "On the Origin of Species".

...no amount of exercise, or habit, or volition, in the utterly sterile members of a community could possibly have affected the structure or instincts of the fertile members, which alone leave descendants. I am surprised that no one has advanced this demonstrative case of neuter insects, against the well-known doctrine of Lamarck.

Matt Young · 27 May 2013

…no amount of exercise, or habit, or volition, in the utterly sterile members of a community could possibly have affected the structure or instincts of the fertile members, which alone leave descendants. I am surprised that no one has advanced this demonstrative case of neuter insects, against the well-known doctrine of Lamarck.

Very interesting, thanks! Lamarckism is not inconsistent with natural selection, and I thought that Darwin (initially at least) accepted the inheritance of acquired characteristics. Do you know whether this statement was included in the earlier editions?

Marilyn · 27 May 2013

DS said:
Marilyn said: The cockroaches progression would be a matter of choice rather than chance.
Sorry Marilyn, wrong once again. It was a random mutation which affected perception and thus behavior. The cockroaches didn't choose the behavior, it was selected on until the allele frequency increased. It's not a "progression" or a "problem" for them and they are not "experimenting", except in the most distorted and anthropomorphic sense. Are you married to Robert Byers by any chance? If not, I would like to introduce you to him. I think you two would get alone famously, even if no one else understood a word.

Don't be so presumptuous.

Marilyn · 27 May 2013

apokryltaros said:
Marilyn said: The cockroaches progression would be a matter of choice rather than chance.
No. It is not a matter of choice on the cockroach's part. Those cockroaches that have a genetic predisposition to crave a glucose-rich diet would die from eating glucose-rich poisoned bait, and have their own sub-population reduced further, while those cockroaches that do not have a genetic predisposition to crave a glucose-rich diet would have their own sub-population increase because fewer members were dying from eating glucose-rich poisoned bait. Or are you saying that cockroaches are choosing to commit suicide or that cockroaches are magically smart enough to go on diets because humans are giving them poisoned food?

I wouldn't say they were magically smart enough to go on a diet magic is a wrong choice of words in this case but it seems they are smart by developing a dislike for glucose due to the persistent rejection of glucose by their body because of the poison. Knowing this dislike either by taste or other senses.

Marilyn · 27 May 2013

DS said:
Marilyn said: The cockroaches progression would be a matter of choice rather than chance.
Sorry Marilyn, wrong once again. It was a random mutation which affected perception and thus behavior. The cockroaches didn't choose the behavior, it was selected on until the allele frequency increased. It's not a "progression" or a "problem" for them and they are not "experimenting", except in the most distorted and anthropomorphic sense.

Why until the allele frequency increased what caused the random mutation of allele frequency to increase why have they not just all died what would spur the allele frequency on to cause a dislike I don't think that would be a random happening that would be a definite evasive maneuver to distinguish harm against survival.

ksplawn · 27 May 2013

Marilyn said:
DS said:
Marilyn said: The cockroaches progression would be a matter of choice rather than chance.
Sorry Marilyn, wrong once again. It was a random mutation which affected perception and thus behavior. The cockroaches didn't choose the behavior, it was selected on until the allele frequency increased. It's not a "progression" or a "problem" for them and they are not "experimenting", except in the most distorted and anthropomorphic sense.
Why until the allele frequency increased what caused the random mutation of allele frequency to increase why have they not just all died what would spur the allele frequency on to cause a dislike I don't think that would be a random happening that would be a definite evasive maneuver to distinguish harm against survival.

The genetic trait which re-wires a cockroach's brain to sense glucose as bitter is one that already existed, even in wild-type populations. It's a feature that was independently popping up in the background. It did not suddenly "evolve" or "adapt" just because people were putting out sweetened baits full of poison. Normally this type of taste perception was not an advantage for the cockroach, because it meant they'd pass over easy meals of high-energy foods loaded with glucose. Hence the relatively low rate of wild-type roaches with this reaction to glucose. However, once there was a significant cost associated with the normal roaches that had a "sweet tooth," like baited poisons, the mathematics of selection suddenly reversed. In human habitats, at least, it became an advantage to turn away glucose-rich foods because those were likely to kill you, removing your genetic load from the population. The roaches who already had the variant form of the genes for processing taste were suddenly being selected for instead of selected against, like their normal cousins. Thus, the frequency of their genetic traits in the population increased significantly. That's the definition of evolution, and this is a great example of evolution through random mutation and (artificial?) selection. What this highlights is how non-reactive most genetic changes are, despite being the basis of adaptation. There's a common misconception that organisms develop mutations in response to some change in the environment. The vast majority of the time, mutations are simply happening in the background regardless of what the environment is doing. It's the changes in selective pressure that decide which variants are successful and which one struggle. This real-world example would make a great case study for introductory biology textbooks to help illustrate the point, and alleviate some of the confusion about how evolution works. Organisms rarely "make" a change themselves, rather they are changed by the whims of inheritance and it's up to the environment to favor them or not. There's no intention, or reaction according to circumstances, involved.

DS · 27 May 2013

Marilyn said:
DS said:
Marilyn said: The cockroaches progression would be a matter of choice rather than chance.
Sorry Marilyn, wrong once again. It was a random mutation which affected perception and thus behavior. The cockroaches didn't choose the behavior, it was selected on until the allele frequency increased. It's not a "progression" or a "problem" for them and they are not "experimenting", except in the most distorted and anthropomorphic sense. Are you married to Robert Byers by any chance? If not, I would like to introduce you to him. I think you two would get alone famously, even if no one else understood a word.
Don't be so presumptuous.

Don't be so obtuse.

DS · 27 May 2013

Marilyn said:
DS said:
Marilyn said: The cockroaches progression would be a matter of choice rather than chance.
Sorry Marilyn, wrong once again. It was a random mutation which affected perception and thus behavior. The cockroaches didn't choose the behavior, it was selected on until the allele frequency increased. It's not a "progression" or a "problem" for them and they are not "experimenting", except in the most distorted and anthropomorphic sense.
Why until the allele frequency increased what caused the random mutation of allele frequency to increase why have they not just all died what would spur the allele frequency on to cause a dislike I don't think that would be a random happening that would be a definite evasive maneuver to distinguish harm against survival.

Because until the allele frequency increased, most of the roaches would still be attracted to glucose. They don't avoid it because they are smart enough, they avoid it because it tastes bad. It tastes bad because to the allele and the allele arose by random mutation. Selection is what caused the allele frequency to increase, those that don't have the right genotype still eat the poison and die. They didn't all just die because not all of them ate the poison and some of them had random mutations that caused them to avoid the poison. The allele frequency doe not cause the dislike, the aversion is caused by the expression of the gene. Over one hundred years of research has shown that such mutations arise randomly, without regard to the needs of the organism, your opinion is irrelevant. So now Marilyn, I have answered all of your questions, even those without question marks. So why don't you answer my questions? Why don't you tell us exactly how the cockroaches are able to tell that they are being poisoned? Why don't you tell us how they are able to figure out the gene to change and the change that needs to be made? Why don't you tell us exactly how they make the change? Why don;t you tell us exactly why they choose this stupid, maladaptive solution instead of any of a hundred choices that would be better? Unless of course you are just another troll who needs to be banished to the bathroom wall.

Marilyn · 27 May 2013

DS said:
Marilyn said:
DS said:
Marilyn said: The cockroaches progression would be a matter of choice rather than chance.
Sorry Marilyn, wrong once again. It was a random mutation which affected perception and thus behavior. The cockroaches didn't choose the behavior, it was selected on until the allele frequency increased. It's not a "progression" or a "problem" for them and they are not "experimenting", except in the most distorted and anthropomorphic sense.
Why until the allele frequency increased what caused the random mutation of allele frequency to increase why have they not just all died what would spur the allele frequency on to cause a dislike I don't think that would be a random happening that would be a definite evasive maneuver to distinguish harm against survival.
Because until the allele frequency increased, most of the roaches would still be attracted to glucose. They don't avoid it because they are smart enough, they avoid it because it tastes bad. It tastes bad because to the allele and the allele arose by random mutation. Selection is what caused the allele frequency to increase, those that don't have the right genotype still eat the poison and die. They didn't all just die because not all of them ate the poison and some of them had random mutations that caused them to avoid the poison. The allele frequency doe not cause the dislike, the aversion is caused by the expression of the gene. Over one hundred years of research has shown that such mutations arise randomly, without regard to the needs of the organism, your opinion is irrelevant. So now Marilyn, I have answered all of your questions, even those without question marks. So why don't you answer my questions? Why don't you tell us exactly how the cockroaches are able to tell that they are being poisoned? Why don't you tell us how they are able to figure out the gene to change and the change that needs to be made? Why don't you tell us exactly how they make the change? Why don;t you tell us exactly why they choose this stupid, maladaptive solution instead of any of a hundred choices that would be better? Unless of course you are just another troll who needs to be banished to the bathroom wall.

Well because, it seems to me then that some have better instincts than others.

phhht · 27 May 2013

Marilyn said: Why until the allele frequency increased what caused the random mutation of allele frequency to increase why have they not just all died what would spur the allele frequency on to cause a dislike I don't think that would be a random happening that would be a definite evasive maneuver to distinguish harm against survival.

Suppose that you have a population of two cockroaches, A and B. Both A and B like glucose. That means that both A and B have the allele, the genetic variant, for glucose attraction. The allele frequency in your population is 100%, because all (both) members of your population have the same allele. Now suppose that A is pierced by a random cosmic ray which happens to alter his genome. (There are lots of causes for mutations, but I've picked a random cosmic ray.) Suppose that, due to the random cosmic ray, cockroach A now has the allele which disfavors glucose, while B remains unaffected. The allele frequency of the gene - that is, the ratio of the number of population members who have the allele to the total number of members of the population - has changed to 50%. Suppose that A and B each produce ten offspring, giving us twenty-two members of our population. Suppose that five of the offspring of A inherit the mutated gene, and that no others do. The allele frequency in our population is now 6 (A plus his five offspring who got the mutant gene) divided by 22, or 27.27%. At this point, natural selection comes into play. All sixteen of the roaches who like glucose eat of the poisoned motel and die, without leaving any progeny. The other roaches, who do not like glucose, eat other stuff and will, later on, reproduce. The size of the population is now six, and the frequency of the allele for disliking glucose is now 100% (the allele for liking glucose has a frequency of 0%.). Notice that there is NO REASON WHATSOEVER to suppose that cockroaches exercise any sort of intentional behavior. Evolution explains what we actually observe WITHOUT ANY NEED for additional assumptions. Everything just works, and nobody needs gods or intelligent cockroaches or mysterious supernatural agents to explain it. Evolution works just fine without any of that stuff. Why drag it in if nobody needs it?

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad · 27 May 2013

With mice, you get taste aversion in response to becoming sick after eating something. That is, mice will "learn" to avoid perfectly good foods that humans lace with poisons that sicken them. Humans likewise, in fact people sometimes hate foods that they ate around the time of becoming sick, even though they know that there is nothing actually wrong with that food.

There may be some of that taste aversion that occurs in cockroaches, for all I know. But of course neither mice nor men pass taste aversion on to their progeny via genes, and that is what is occurring with the German cockroaches. From the NYT article I can't see that they've completely ruled out epigenetic inheritance, but the paper may. Even if it were epigenetics rather than genetics, though, it would still be natural selection, it just wouldn't last through all generations. Yet epigenetic changes could get cockroaches through a temporary situation that lasts for several generations.

I'm guessing that it really is genetic, though, from how the article is written.

Glen Davidson

Scott F · 27 May 2013

Matt Young said:
As I understand Lamarckism, there’s no “intention” involved. An individual animal stretches its neck, its neck gets longer, or it gets better at what it does, and this change is then passed onto the next generation.
No. Lamarck was smarter than that - spaniels are not born with their tails bobbed nor Jewish boys circumcised. Intentionality was involved: The giraffe had to "will" its neck to get longer; the blacksmith had to will his muscles to be bigger. Lamarck's view was not irrational, and it was completely consistent with the view that some sort of "life force" propelled living organisms.

Interesting. I wasn't suggesting that Lamarckism was "irrational", or even "unscientific", particularly for his time. Mine is just a wiki-level of understanding, but the Wiki description doesn't imply a place for "intentionality". It talks about "need", "resulting in change in behavior, bringing change in organ usage and development, bringing change in form over time". As you say, this description does not appear to be inconsistent with either intentionality or with natural selection, but it doesn't require intentionality. If I understand the description of Lamarck's theory, the "need" response to a change in the environment doesn't require "intelligence". It simply requires some kind of undirected striving to overcome the environmental stress. In contrast, if I understand Ray's position correctly, he has said that the organism recognizes a need, and the non-physical "intelligence" of the organism intentionally decides upon and implements a physical change that will meet that need. While this is not incompatible with Lamarckism, it seems to me to be a distinct "spiritual" (if you will) addition that is not part of the original Lamarck proposal. Unless the Wiki description is too simplistic, and is leading me astray in understanding Lamarck's position. The "intentionality" part seems more compatible with what Wiki describes as Neo-Lamarckism, which I had not been aware of until just now. Perhaps, as harold suggests, this is more a matter of semantics. Regardless of whether my understanding of Lamarck is entirely correct or not, I think my conclusion is still valid: that thinking of all anti-evolutionists as "Biblical Creationists" (though most are) and responding accordingly can lead to unexpected responses and more confusion than would be otherwise necessary. It does suggest a need to learn more about Lamarck. Given that it was an apparently popular view in the day, it would be helpful to understand the ways in which people can misunderstand something, and why such a view had/has such strong appeal.

DS · 27 May 2013

Marilyn said:
DS said:
Marilyn said:
DS said:
Marilyn said: The cockroaches progression would be a matter of choice rather than chance.
Sorry Marilyn, wrong once again. It was a random mutation which affected perception and thus behavior. The cockroaches didn't choose the behavior, it was selected on until the allele frequency increased. It's not a "progression" or a "problem" for them and they are not "experimenting", except in the most distorted and anthropomorphic sense.
Why until the allele frequency increased what caused the random mutation of allele frequency to increase why have they not just all died what would spur the allele frequency on to cause a dislike I don't think that would be a random happening that would be a definite evasive maneuver to distinguish harm against survival.
Because until the allele frequency increased, most of the roaches would still be attracted to glucose. They don't avoid it because they are smart enough, they avoid it because it tastes bad. It tastes bad because to the allele and the allele arose by random mutation. Selection is what caused the allele frequency to increase, those that don't have the right genotype still eat the poison and die. They didn't all just die because not all of them ate the poison and some of them had random mutations that caused them to avoid the poison. The allele frequency doe not cause the dislike, the aversion is caused by the expression of the gene. Over one hundred years of research has shown that such mutations arise randomly, without regard to the needs of the organism, your opinion is irrelevant. So now Marilyn, I have answered all of your questions, even those without question marks. So why don't you answer my questions? Why don't you tell us exactly how the cockroaches are able to tell that they are being poisoned? Why don't you tell us how they are able to figure out the gene to change and the change that needs to be made? Why don't you tell us exactly how they make the change? Why don;t you tell us exactly why they choose this stupid, maladaptive solution instead of any of a hundred choices that would be better? Unless of course you are just another troll who needs to be banished to the bathroom wall.
Well because, it seems to me then that some have better instincts than others.

Well that certainly answers all of my questions Marilyn. Thanks so much for that enlightening reply. Troll it is then.

Matt Young · 27 May 2013

I may indeed be conflating Lamarckism with neo-Lamarckism, but I thought that more was involved than just need -- the giraffe needed more than to be taller; it had to stretch its own neck if it was to pass its longer-neck trait to its descendants. Notice also that the Darwin quotation above,

...no amount of exercise, or habit, or volition, [my italics]...

uses the term "volition," though that must have been written long after Lamarck's time. Maybe someone more expert can shed some light on the chronology.

Marilyn · 27 May 2013

phhht said: (There are lots of causes for mutations, but I've picked a random cosmic ray.)

Really.

phhht · 27 May 2013

Marilyn said:
phhht said: (There are lots of causes for mutations, but I've picked a random cosmic ray.)
Really.

Yes, I really did. So what?

Matt Young · 27 May 2013

Yes, I really did. So what?

Please, no bickering.

harold · 27 May 2013

ksplawn said -

The genetic trait which re-wires a cockroach’s brain to sense glucose as bitter is one that already existed, even in wild-type populations. It’s a feature that was independently popping up in the background. It did not suddenly “evolve” or “adapt” just because people were putting out sweetened baits full of poison. Normally this type of taste perception was not an advantage for the cockroach, because it meant they’d pass over easy meals of high-energy foods loaded with glucose. Hence the relatively low rate of wild-type roaches with this reaction to glucose. However, once there was a significant cost associated with the normal roaches that had a “sweet tooth,” like baited poisons, the mathematics of selection suddenly reversed. In human habitats, at least, it became an advantage to turn away glucose-rich foods because those were likely to kill you, removing your genetic load from the population. The roaches who already had the variant form of the genes for processing taste were suddenly being selected for instead of selected against, like their normal cousins. Thus, the frequency of their genetic traits in the population increased significantly. That’s the definition of evolution, and this is a great example of evolution through random mutation and (artificial?) selection.

This is likely to be about right but it may be a bit more complicated. Aversion to glucose might be related to a recessive allele. Under normal circumstances homozygotes might be selected against, but heterozygotes might not be. The heterozygotes might like glucose just a little less than cockroaches without the allele at all. The allele might or might not be linked to other alleles with significant effects. Or, not mutually exclusively, there could be multiple genes involved. It doesn't have to be a one gene effect. There could have been a spectrum of reaction to glucose in the naive population, ranging from rare individuals with aversion through varying degrees of attraction, based on an array of alleles. Cockroaches have short generations and the poison is probably never perfectly effective. Numerous pathways to the glucose aversion point are possible. The only way to know what really happened is to do molecular genetic and neurobiological studies. Phht said -

Both A and B like glucose. That means that both A and B have the allele, the genetic variant, for glucose attraction. The allele frequency in your population is 100%, because all (both) members of your population have the same allele. Now suppose that A is pierced by a random cosmic ray which happens to alter his genome. (There are lots of causes for mutations, but I’ve picked a random cosmic ray.) Suppose that, due to the random cosmic ray, cockroach A now has the allele which disfavors glucose, while B remains unaffected. The allele frequency of the gene - that is, the ratio of the number of population members who have the allele to the total number of members of the population - has changed to 50%. Suppose that A and B each produce ten offspring, giving us twenty-two members of our population. Suppose that five of the offspring of A inherit the mutated gene, and that no others do. The allele frequency in our population is now 6 (A plus his five offspring who got the mutant gene) divided by 22, or 27.27%. At this point, natural selection comes into play. All sixteen of the roaches who like glucose eat of the poisoned motel and die, without leaving any progeny. The other roaches, who do not like glucose, eat other stuff and will, later on, reproduce. The size of the population is now six, and the frequency of the allele for disliking glucose is now 100% (the allele for liking glucose has a frequency of 0%.). Notice that there is NO REASON WHATSOEVER to suppose that cockroaches exercise any sort of intentional behavior. Evolution explains what we actually observe WITHOUT ANY NEED for additional assumptions. Everything just works, and nobody needs gods or intelligent cockroaches or mysterious supernatural agents to explain it. Evolution works just fine without any of that stuff. Why drag it in if nobody needs it?

This is a model that incorporates mutation and natural selection, but it's less likely than what ksplawn is saying. New mutations may or may not be involved. It's highly unlikely that a one generational event like this occurred. It doesn't have to be a one gene effect. This analysis ignores zygosity, or at best, assumes that a dominant allele is involved. However, both of these models are within the realm of possibility, without invoking magic. Neither relies on supernatural or inexplicable events.

harold · 27 May 2013

Matt Young said: I may indeed be conflating Lamarckism with neo-Lamarckism, but I thought that more was involved than just need -- the giraffe needed more than to be taller; it had to stretch its own neck if it was to pass its longer-neck trait to its descendants. Notice also that the Darwin quotation above,
...no amount of exercise, or habit, or volition, [my italics]...
uses the term "volition," though that must have been written long after Lamarck's time. Maybe someone more expert can shed some light on the chronology.

It does get semantic. I use the term “Lamarckism” as I was taught to use it - if the environment directly produces a targeted mutation that humans would perceive an organism as “needing”, wanting”, or “striving for” (for its descendants, that is), that’s all Lamarckism to me. Whether some sort of conscious application of psychic powers by the short-necked giraffe ancestor is required is moot. However, I guess we could make the distinction, within Lamarckism, between conscious and unconscious targeting of the mutation. It’s still Lamarckism to me because the environmental situation leads to a targeted mutation - no selection necessary. It still all has the same problems I mentioned above. The “conscious” idea raises a big new problem - why aren’t we humans conscious of targeting our own genomes, if that’s how mutation works? I have learned to recognize - and dislike - the term “neo-Lamarckism” as a very clumsy reference to a perfectly valid scientific observations. Some organisms have evolved DNA repair mechanisms which are less effective in a “stressful” environment. As far as I know, human DNA repair enzymes don’t have this characteristic, but some types of lake fish in Africa show this. It really only makes sense in organisms with vast numbers of offspring and high mortality of young offspring. A decently supported hypothesis is that when new predators or the like bring “stress” to the environment, a more diverse brood of young is more likely to contain rare individuals with new modifications that might be useful against the new stress. In a more stable environment, this tendency would be selected against. Because, in this model, the environment impacts on mutation rate in a meaningful way, this is sometimes, execrably in my opinion, but nevertheless, sometimes referred to as “neo-Lamarckism”. Anyway, though, that’s just my personal understanding, and if the general meaning of the word slowly changes, so be it.

Mark Sturtevant · 27 May 2013

The roach article reminds me of a taste variation seen in humans. I am referring to the classic traits of being a 'taster' for the bitter chemical phenylthiocarbamide (PTC), which is a dominant allele. Homozygotes for a mutation (possibly for a particular taste receptor protein, but it could be something else) are 'non-tasters'. They cannot taste this chemical. There are variations in what individuals in a population can taste or not taste, and these variations can have a genetic basis and so be subjected to natural selection. Of course the roach situation is especially interesting since it appears to result in a difference in an interpretation of what they taste. There are a variety of ordinary ways in which this could occur (in theory).

harold · 27 May 2013

Of course the roach situation is especially interesting since it appears to result in a difference in an interpretation of what they taste. There are a variety of ordinary ways in which this could occur (in theory).

Meaning "interpretation" in the sense of "behavioral reaction to", I presume.

Matt Young · 27 May 2013

It does get semantic. I use the term “Lamarckism” as I was taught to use it - if the environment directly produces a targeted mutation that humans would perceive an organism as “needing”, wanting”, or “striving for” (for its descendants, that is), that’s all Lamarckism to me. Whether some sort of conscious application of psychic powers by the short-necked giraffe ancestor is required is moot. However, I guess we could make the distinction, within Lamarckism, between conscious and unconscious targeting of the mutation. It’s still Lamarckism to me because the environmental situation leads to a targeted mutation - no selection necessary.

I think the point is that the organism has to do something positive in order for the trait to "take." That is why the giraffe's neck gets longer with succeeding generations but the spaniel's tail does not become bobbed. Psychic powers are irrelevant (also nonexistent). All you have to think is that the somatic cells communicate acquired characteristics to the germ cells, as Darwin speculated. As far as I know, Lamarckism did not involve the supernatural.

Scott F · 27 May 2013

harold said: The “conscious” idea raises a big new problem - why aren’t we humans conscious of targeting our own genomes, if that’s how mutation works?

That's always been my response. If the bacterium can "will" itself a flagellum, why can't I will myself all sorts of better features? Certainly my "intelligence" is "better" in some sense than that of the bacterium. Certainly my imagination is. Ray's never been able to answer that one.

Marilyn · 28 May 2013

I’m glad that Matt posted this subject. I really appreciate your explanation Phhht it has made the circumstances very clear so I can understand better. It is an important subject to me as there has been talk about insects been put into the human food chain so how poison affects these and rodents is a concern to me for any side effects that possibly would not be noticed in the near future.

phhht · 28 May 2013

I'm glad you found it helpful. Be sure to note that the oversimplified example I gave does not correspond exactly to the situation of the cockroaches in the paper.

Marilyn said: I’m glad that Matt posted this subject. I really appreciate your explanation Phhht it has made the circumstances very clear so I can understand better. It is an important subject to me as there has been talk about insects been put into the human food chain so how poison affects these and rodents is a concern to me for any side effects that possibly would not be noticed in the near future.