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Junior Member (Idle past 6131 days) Posts: 2 From: Alabama, USA Joined: |
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Author | Topic: Mimicry: Please help me understand how | |||||||||||||||||||||||||||
MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
I have adressed the issue in the thread "Mimicry and neodarwinism". Dawkins and some contibutors here propose small gradual steps as explanation. In the case when one butterfly resembles some other unpalatable butterfly (Batesian or Mullerian mimicry) such explanation is not accepted in scientific community as far as I can judge. Dawkins in not scientist strictly speaking. I have already quoted Nijhout who have made many researches in the area of butterfly mimimicry and who wrote:
"Initial step in the evolution of mimicry is likely to have been due to a genetic effect of large magnitude". It is necessary that first step towards model is great in order to deceive predator. Predators sometimes taste also unpalatable species. The problem of mimicry is much more complicated as it may seems. Very often mimics outnumber models. Sometimes we observe polymorphic mimicry - some races of the same butterly species mimic different unpalatable species but some races of it do not. So we have mimic and non-mimic of the same species and both thrive very well. On the meadow you can observe bright palatable and bright unpalatable butterflies as well as some mimic species. All of them thrive and live on the same area. Obviously in such case one have to ask question how natural selection works in reality. I quoted also Punnet and Goldschmdt, both prominent scientists, who claimed that mimicry arouse suddenly, by saltus. Other, non-darwinian explanation are due some kind of "synchronicity". Anyway gradual steps seems to be unplausible explanation in the case of Mullerian mimicry, when one unpalatable butterfly mimics another unpalatable species. In that case small change would shift off resemblance from aposematic coloration of own species. And yet it would not give fully protection of coloration of the model species. Again we should explain the fact that on the same area thrive Mullerian mimics and also palatable non-mimic species as well. I can hardly imagine what kind of natural selection took effect on the mimic species and very often close related species on the same area was somehow ovelooked by it. Edited by AdminWounded, : Added link to older thread.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
MartinV, whatever your opinion on this, might I politely ask that you allow this thread to develop with as little input as possible - even if it is only to allow our new member to get noticed. Judging by how much debate your views put forward, our new member might be overwhelmed.
There was no response 10 days so I feel free to add something. According neo-darwinsim wasps have aposemtic coloration to deter predators. Butterfly Aegeria apiformis look and buzz like a wasp. One would thing that the butterfly has some survival advantage looking like a wasp. But probably no scientist has made a research to prove it. Wasps have many bird's predators who eat them. One of them is bird Merops apiaster living in Europe - Bee eater:
quote: European bee-eater - Wikipedia or curl-crested jay (Cyanocorax cristatellus):
quote: Bird predation on nest of a social wasp in Brazilian cerrado It is only neo-darwinian pressuposition that a butterfly mimicing wasps are protected having wasp coloration. Probably no serious research has been done yet. Edited by MartinV, : No reason given.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
Thank you for your response. I would appeciate if the experiment was accessible on-line for closer examination. I have 2 points:
1) Genera Micurus (according Robert Mertens 1954) in Brazil is very poisonous and no predator survive its biting. Consequently no one can remember the species as dangerous. 2) I don't know if the species are diurnal or nocturnal. At least Scarlet snake you mentioned as mimic is nocturnal species. I do not see what kind of natural selection is acting to diurnal species to look like bright colored poisonous model.
quote: Cemophora coccinea - Scarlet snake -- Discover Life
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
I'm willing to bet that lepidoptera has more predators than vespa/vespidae. This is doubly backed up by the fact that bee-eaters also eat moths anyway. I think it should be fairly apparant that reducing the number of potential predators conveys a significant advantage.
I wouldn't bet. Such a conclusion follows only from darwinistic explanation of mimicry. A serious research is needed. I have written about it in the previous thread. Distinguished American ornitologist who disputed with Poulton about this issue was McAtee from Biological Survey Division from United States Department of Agriculture. He made great researches on this field and he came to the conclusion that birds eat same proportion of aposematics and mimetics species as are they proportions among insects. McAtee therefore thought that such aposematic/mimic colororation are inefficient. He also refuted that birds eat plentifully butterflies studying so-called beak marks. See my post 162 on it: http://EvC Forum: Mimicry and neodarwinism -->EvC Forum: Mimicry and neodarwinism Another problem is the discussed aposematic coloration of snakes. It would pressupose that almost all predators have experience with it if they avoid them. It is different for a bird to have experience with an unpalatble butterfly and with a deadly poisonous snake I would say. Avoiding aposematic snakes could be probably inborn. Same for avoiding poisonous mushrooms.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
This is exactly what I thought. The interesting thing about the experiment though is that the animals in the region must be aware that such coloration indicates a poisonous snake. What else would explain the differences in the number of attacks within and without of the area? The experiment consisted of {hundreds} of snakes (thats the best information I have available).
I would like to know more about the research.I have tried to find it out at inet but without success. Your mentioned research contradicts other observation done by S.M.Smith (1975, 1977, 1978 ,1980) that young birds (Tyrannidae) have aversion to coloration of Corals. Generally speaking there is probably an aversion in vertebrata to black and red color patterns. So considering this conclusion the research you quoted contradicts this fact - birds from other area attacked coral snakes. S.M.Smith: Innate recognition of coral snake pattern by a possible avian predator. Science 187:759-760 1975 So or so the aversion to corals are most probably innate to some birds. Because such aversion is not heritable it origin should be only random mutation that was selected by NS (according darwinism of course). Dunn (1954) mentioned that snakes having this coloration in Panama are feeding with other snakes (85%). Most of them are hunting during night so vision oriented predators probably do not play any role. Dunn: The coral snake "mimic" in Panama.Evolution 8:97-102, 1954. I don't have access to the article, but it is here with interesting first page. JSTOR: Access Check(195406)8:2%3C97:TCS'PI%3E2.0.CO;2-Q And to confuse the situation even more, a research from 1995:
quote: http://www.springerlink.com/content/l60j183265852v30/ The problem of mimicry of coral snakes is more complicated as it may seems at first glance.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
Now you suggest further study is required, and that's fine. Further study is always required, and entomologists have a lot of work to do!
The problem of the so-called mimicry had been studied very thoroughly before second WW in Germany. The problem of evolution of coloration of butterflies (and lizards) seems to follow a rule. Theodor Eimer observed the fact that evolution of color patterns on butteflies wings (and lizards) follows transformation rules (Homoegenesis). Many authors confirmed that this observation is correct. First lungitudinal stripes, their dissolution into spots and tranformation of these spots into transverse striping and finally into one-coloured appereance. He described even leaf-mimic butterflies and their trasformation from the beginning to the end (break-up of mimicry patterns which should have given "survival advantage" to species and should be strongly selected against its break-up according darwinism.) This is only one page, but very interesting about undulatory development, have a look if you like:
http://links.jstor.org/... In the described process natural selection plays no role. Edited by MartinV, : No reason given. Edited by Adminnemooseus, : Shorted display form of link, to restore page width to normal.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
Mimicry is more than just having similar colouration, of course, and I'd be surprised if you can find a good reason for some of the more elaborate mimics that did not require some reference to natural selection.
You know we have different opinions and resources but preliminary I would like to stick at Eimer's theories. First I am not sure if his work has been ever translated into English. German and English biology developed almost independently before first WW. Eimer agreed with Darwin that dull colors precedes development of brighter ones. Darwin considered the most brighter animals as evolutionary more developed. Eimer saw the transformation sequence closing with black or white color. Comparing many butterflies species he came to conclusion that one-colored coloration is more progressive and it ended developmental cycle. Transformation of color patterns on butterfly wings proceeds from original 11 stripes towards one-color. According Eimer the mimetism in butterflies is due to the fact that different species are in differnt transformation sequence from 11 stripes towards black color (Papilionidi) or white (Pieridi). Mimetism is therefore pure chance of being on the same transformation level during development. It is indepent from selection and what's more it is independent from geographical area it occurs. For Eimer there is consequently no problem of mimetism between species living in different geographical areas - something I mentioned in previous thread.Darwinism (Poulton) tried to explain such mimetism by selective pressure by migratory birds. It is just some of Eimer thoughts and I hope my english is underestandable for you. Take it as a history of biological thinking.I am unable to judge if his conclusions he devoted his life are to be scietfically proved.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
Wounded King,
much of your objections I adreesed in my previous post to Modulous.Anyway I am not sure - as we discussed before - that genetical background can explain mimetism. Color sequences in butterflies were studied by Piepers (1898), Reuss (1918), Tshirvinskij (1925), Giesberg (1929). Lucas. H. Peterich (1972,1973) Their works are almost ignored by Nijhout whom we discussed before. He has never mentioned Eimer, who described the same phenomena of so-called Liesegangs figures btw. Nijhout called them "ripple pattern", wheras for Eimer it is "Rieselung" and for Suffert (1929) "Rhytmische Flugelmusterung". Much more can be found in Stanislav Komarek book:"Mimicry, Aposematism and Related Phenomena in Animals & Plants: Bibliography 1800-1990" Stanislav Komarek: used books, rare books and new books @ BookFinder.com Edited by MartinV, : No reason given.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
You have never given any coherent reason why however. All you seem to do is stick your fingers in your ears and ignore any genetic research, except when trying to quote mine it to fit your preconcieved ideas.
Eimer seems to be some kind of lamarckist but I am not sure. But I have read that he proposed temperature etc as source of changes. In such cases genes might have play no signifficant role. We are probably facing phenocopies, what have been observed in many interesting experiments.
quote: Goldschmidt was a prominent saltationist who coined the term phenocopy.
quote: Just for a record. "Genetic research" do not explain deep secrets of life sometimes. Out of Print Edited by MartinV, : No reason given. Edited by MartinV, : No reason given.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
all you seem to have just done is illustrate my point, just giving references is pointless if you haven't read and understood them, and if reading that Gilbert article lead you to believe it was discussing the limits of developmental genetics then you have severe reading comprehension problems.
Your responses are sometimes very instructive. Unfortunatelly it is not the case of your latest post. You focused your attention on "genetic assimilation" instead of "phenocopies" I wrote about. It is a little bit inaccurate to claim that the article supports your ideas. We are discussing non-darwinian explanation of phenomena of butterfly mimicry. As you may have noticed from the article - you have read it so carefully obviously, because you denigrated me - mainly three names were mentioned there: 1) Waddington2) Schmalhausen 3) Goldschmidt No one of them can be called a "neodarwinist". If you like I will quote you some opinion about neodarwinism from Waddington and Schmallhausen (malgausen - even in Russian language if you like. His work is not very known, even though very interesting). Goldschmidt was a prominent saltationist, there is no doubt of it. So I don’t see reason for your enthusiam that those three great scientists with their experiments should support your neodarwinistic views. I don't see a point why you has written so long about "genetic assimilation" and calluses. It has nohing to do with phenocopies I wrote about. If you have had read the article more carefully (instead of denigrating my reading abilites) you may had been noticed this sentence:
quote: You can read - "converse of genetic assimilation".
P.S. That is a great article, one of the clearest explanations of genetic assimilation I have come across.
I agree. But I was not writing about genetic assimilation. The article in no way support you neodarwinistic explanation of secrets of life - even if you think it does. --- Btw. one would say that all genetic assimilation stuff is an interesting way how to apply neodarwinism to facts that support lamarckism. Such experiments would support more "inheritance of acquired traits".Many scientists support such view before 2WW - but it was not the case of mentioned Goldschmidt - but after 2WW such experiments are almost not done anymore. But this is another story. Edited by MartinV, : No reason given. Edited by MartinV, : thoughts about lamarckism added.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
Mimicry is more than just having similar colouration, of course, and I'd be surprised if you can find a good reason for some of the more elaborate mimics that did not require some reference to natural selection. I'd urge you to pick papers from after the discovery of genetics and the synthesis of same with other evolutionary mechanisms.
One would say the more resemblance to an unpalatable model the more survival advantage of a mimic. One would suppose that most of the mimics are perfect ones. This is obviously not the case. The most mimics are imperfect. Either we are living in the period of "evolution in action" or another force explaining mimicry should be reconsidered:
quote: What a mess governs in darwinian explanation of the above mentioned fact! I have written in my previous thread that even if mimicry in insect realm is known more than 150 years there is no plausible explanation of it yet. There are many neodarwinian "armchair" theories that contradict each other essentailly. It is very bold to presume that neodarwinism has explanation of mimicry.
quote: Check it yourselves in modern summary of the phenomenon of mimicry. Birds are sometimes not mislead by mimics (Dlusski experiments) as selectionists so boldly claim: http://eprints.nottingham.ac.uk/...6/01/ImperfectMimicry.pdf
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
Perhaps you should read the above mentioned article. The article mentioned Franz Heikertinger only in flight and he deserves more I would say. Franz Heikertinger was an Austrian entomologist who refuted selection as source of mimicry.
I have not studied the matter in any detail at all, so I am at great risk of oversimplifying this, but to me it seems very obvious.
I agree. It seems to be obvious at the first glance. But the problem is that the matter is very complicated. I addressed many problems here and at closed thread Mimicry and neodarwinism http://EvC Forum: Mimicry and neodarwinism -->EvC Forum: Mimicry and neodarwinism
Even if it only works 1% of the time, there will be positive selection pressure.
So why imperfect mimics are not improved by natural selection even more? The only force working against "positive selection pressure" is "kin selection", something very dubious as you can see from the article.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
You know, biologists? The people who get out of their "armchairs" and study biology, as opposed to the people who sit on their lazy arses posting lies and gibberish on Internet forums.
I agree with you. Edited by MartinV, : No reason given.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
I don't like the way Dr. Adequate is responding to my posts. Does he obey the EvC rules?
I suppose a man who describes insect predators as "myopic and dull-witted animal" which are probably responsible of stunning leaf-insect mimics that such a man does not have any right to call my reasoning " the idiotic garbage you've made up in your head". Thank you for your response.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
We are a little bit in scholastical dispute over mimicry. We should give some examples and express our positions more clearly.
In the previous article authors and scientists saw "imperfect" wasp-mimics almost everywhere - that's probably why it's explanation was so messy. Another position is that mimicry is often only neodarwinian invention - Franz Heikertinger was a prominent proponent of it. Probabaly in many cases we are facing only the fact of covergence and chance. Darwinism often support it's view by presenting "stunning" examplesof mimics. One of them is "wasp-mimic" Trochilium apiforme - I don't know it's english name, but here is the picture: trochiliumapiforme
Anyway we should be aware that family Sessidae is characterised as clearwing moths and involve more than 600 different species. Some of them is to be found at wikipedia: Sesiidae - Wikipedia See especially Bambecia chrysidiformis. I would say even having transparent wings and yellow band there is no way resemblance to wasps. So the point is this: How is it possible that 600 different Sessidaes species are often more common and outnumber "mimic" Trochilium? Are we to accept an implausible idea that all of them are imperfect mimic of wasps? Or was there strong selective pressure on Trochylium to look like wasp, but the other species of the family have other protection? What? So the outcome should be this one - the range, extent of different colors of Sessidae is so great that Trochylium apiforme would exists in the same coloration and shape even if there were no wasps on the Earth. Edited by MartinV, : No reason given.
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