Register | Sign In


Understanding through Discussion


EvC Forum active members: 65 (9162 total)
4 online now:
Newest Member: popoi
Post Volume: Total: 915,817 Year: 3,074/9,624 Month: 919/1,588 Week: 102/223 Day: 0/13 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Mimicry: Please help me understand how
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 8 of 241 (411181)
07-19-2007 8:49 AM
Reply to: Message 1 by Lampropeltis
07-14-2007 3:04 PM


?, considering that a random mutation that led to individuals appearing EVER SO SLIGHTLY like bird droppings would not have been significant enough (in my mind) to result in differential survivability leading to differential reproductive success. How can appearing EVER SO SLIGHTLY like bird droppings be advantageous?
Interesting question.
First of all, in general, camouflage and mimicry always works better at a distance. Any slight improvement would reduce the minimum distance at which the camouflage is effective.
Take, for example, soldiers' khakis. They don't make a soldier look very vegetation, but at a distance they do offer concealment.
In the case of bird-dropping mimics, being dull-colored and speckled is already a form of camouflage. (Speckles break up the three-dimensional form of an object, making it harder to see: again, the priciple is applied in military khaki.) If a particular variation of such markings also has some tendency to make the creature look like bird-droppings to any bird that does spot the caterpillar, that's obviously an advantageous trait.
Welcome to the forums.

This message is a reply to:
 Message 1 by Lampropeltis, posted 07-14-2007 3:04 PM Lampropeltis has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 30 of 241 (414228)
08-03-2007 2:45 PM
Reply to: Message 15 by MartinV
08-02-2007 2:49 AM


Re: Scarlet King Snake
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.
Well, that made me chuckle.
Natural selection operates on genes, not memories.
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.
Mmm ... I wonder if there's such a thing as a nocturnal predator?
I wonder if diurnal species ever eat nocturnal species?
Golly, nature's such a puzzle, isn't it?

This message is a reply to:
 Message 15 by MartinV, posted 08-02-2007 2:49 AM MartinV has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 38 of 241 (417776)
08-24-2007 2:29 PM
Reply to: Message 36 by MartinV
08-24-2007 12:21 AM


Re: mimicry isn't the problem, then
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.
But he cunningly disguised this so that no-one noticed it.

This message is a reply to:
 Message 36 by MartinV, posted 08-24-2007 12:21 AM MartinV has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 39 of 241 (417778)
08-24-2007 2:39 PM
Reply to: Message 34 by MartinV
08-23-2007 3:35 PM


Re: mimicry isn't the problem, then
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.
Why one "one" suppose that? Was "one" dropped on "one's" head when "one" was a child?
Either we are living in the period of "evolution in action" ...
As is, of course, the case.
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.
Nice rhetoric, shame about the facts.
You remember facts? Those things real biologists like so much?
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.
Birds are sometimes not mislead by mimics (Dlusski experiments) as selectionists so boldly claim:
If you believe that "selectionists" claim that mimicry is always successful, then you appear to have mistaken a stupid, clumsy, ugly straw man of your own construction for "selectionists".
Which proves, I guess, that mimicry need not always be perfect. If you can mistake the idiotic garbage you've made up in your head for anything connected with mainstream biology, then obviously a resemblance need not be 100% ... or 50% ... or 1% ... in order to deceive a sufficiently myopic and dull-witted animal.

This message is a reply to:
 Message 34 by MartinV, posted 08-23-2007 3:35 PM MartinV has replied

Replies to this message:
 Message 40 by MartinV, posted 08-24-2007 3:06 PM Dr Adequate has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 42 of 241 (417829)
08-24-2007 8:35 PM
Reply to: Message 41 by MartinV
08-24-2007 3:49 PM


Re: To administrator
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".

This message is a reply to:
 Message 41 by MartinV, posted 08-24-2007 3:49 PM MartinV has not replied

Replies to this message:
 Message 43 by Adminnemooseus, posted 08-24-2007 9:26 PM Dr Adequate has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 50 of 241 (419739)
09-04-2007 2:43 PM
Reply to: Message 49 by MartinV
09-04-2007 2:06 PM


Re: What is "darwinian" mimicry in fact?
Because ladybugs are very colorfull darwinists need some explanation of it. Of course they have only one explanation - ladybugs are aposematic because they are poisonous.
And hey, look, we're right.
Bur theory is theory and facts are facts.
And isn't it great how the facts always fit our theory? This is what we call "empirical verification".
Facts are science, not preconcieved armchair theories of Darwin, Bates, Wallace and Dawkins - those men who tried to explain so-called mimicry via natural selection.
Ah yes, armchair science. As exemplified by Darwin's book The Voyage of the Armchair, and Wallace's work Travels in the Amazon and Malay Archipelago in an Armchair.
Edited by Dr Adequate, : No reason given.

This message is a reply to:
 Message 49 by MartinV, posted 09-04-2007 2:06 PM MartinV has not replied

Replies to this message:
 Message 52 by crashfrog, posted 09-04-2007 3:27 PM Dr Adequate has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 57 of 241 (421920)
09-15-2007 1:14 AM
Reply to: Message 56 by MartinV
09-15-2007 12:32 AM


Re: Ladybirds and neodarwinian "natural selection"
MatinV, all the flatulent twaddle in the world won't get rid of the facts that:
(1) Ladybirds are poisonous.
(2) Predators avoid species with aposematic colouration.
Edited by Dr Adequate, : No reason given.

This message is a reply to:
 Message 56 by MartinV, posted 09-15-2007 12:32 AM MartinV has replied

Replies to this message:
 Message 60 by MartinV, posted 09-15-2007 2:15 AM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 58 of 241 (421928)
09-15-2007 1:54 AM
Reply to: Message 53 by MartinV
09-04-2007 4:21 PM


Re: What is "darwinian" mimicry in fact?
Don't ridicule yourself please. Dr. Adequate represents darwian aggresive ignorance sufficiently.
Ah yes, the "aggressive ignorance" of someone who knows that Darwin and Wallace weren't armchair scientists. As opposed, I suppose, to the courteous wisdom of someone who pretends that they were.
Wallace described Papilio butterflies flight as slow and weak and "we can make conlusion they posses some protection"...
And he was absolutely right --- they are Batesian mimics.
"Drusilla are common and have slow flight...it seems having some protection..."
And golly gosh, he was right again! See Brand, J.M., Blum, M.S., Fales, H.M., and Pasteels, J.M. 1973b, The chemistry of the defensive secretion of the beetle, Drusilla canaliculata. J. Insect Physiol. 19:369-382.
Bates 1861: "The reason of mimicry CANNOT be other as natural selection..."
Oh look, Bates was right!
Have you ever noticed how evolutionists are always right?
Darwin adressed the problem of mimicry only from Bates. According Darwin only Belt "proved" it. Belt had made som experiments with apes.
Could we have that in English, please, and possibly with some references?
In the real world, which differs markedly from the fantasy world in your head, Darwin discussed forms of mimicry other than Batesian:
"Nor can I see any force in Mr. Mivart's difficulty with respect to "the last touches of perfection in the mimicry;" as in the case given by Mr. Wallace, of a walking-stick insect (Ceroxylus laceratus), which resembles "a stick grown over by a creeping moss or jungermannia." So close was this resemblance, that a native Dyak maintained that the foliaceous excrescences were really moss. Insects are preyed on by birds and other enemies whose sight is probably sharper than ours, and every grade in resemblance which aided an insect to escape notice or detection, would tend towards its preservation; and the more perfect the resemblance so much the better for the insect. Considering the nature of the differences between the species in the group which includes the above Ceroxylus, there is nothing improbable in this insect having varied in the irregularities on its surface, and in these having become more or less green-coloured; for in every group the characters which differ in the several species are the most apt to vary, while the generic characters, or those common to all the species, are the most constant." (Charles Darwin, On the Origin of Species)
---
Could I also point out that in the 21st century we know rather more than people did in the 1860s, and that quoting from works of that date in an attempt to suggest that evolutionary explanations of mimicry are speculative or unproven is therefore very, very, very, very stupid.
Esecially when, in the light of modern knowledge, these early speculations turn out to be absolutely right in every respect.
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.

This message is a reply to:
 Message 53 by MartinV, posted 09-04-2007 4:21 PM MartinV has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 61 of 241 (421932)
09-15-2007 2:20 AM
Reply to: Message 56 by MartinV
09-15-2007 12:32 AM


Re: Ladybirds and neodarwinian "natural selection"
I am afraid no visualy oriented predator is scared by "reflex bleeding".
Again, a glance at the real world is rewarding. Predators which have a sense of taste or smell are repulsed by the pyrazine, and learn to associate this with visual cues. See, for example, Skelhorn J. & Rowe C., Prey palatability influences predator learning and memory.

This message is a reply to:
 Message 56 by MartinV, posted 09-15-2007 12:32 AM MartinV has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 63 of 241 (421938)
09-15-2007 2:30 AM
Reply to: Message 60 by MartinV
09-15-2007 2:15 AM


Re: Ladybirds and neodarwinian "natural selection"
Poisonous for whom? 1 gram of insect poison Cantharidin for instance is enough to kill 20.000 kg of people, but only 7 kg of hedgehog species. Insect eating hedgehogs, crabs, frogs etc are almost unsensitive to the poison. Eating a beetle with this poison can kill you.
Many species of birds are completely unsensitive to the poison (Otis tarda).
Well, golly gosh, it's almost as though natural selection favors resistance to insect toxins more in insectivores than in non-insectivores.
I wonder if you can figure out why.
It is only bold darwinian pressuposition.
It's a fact. Even "naive" handreared animals will avoid animals with aposematic coloration by instinct. See, for example, Smith S., Innate Recognition of Coral Snake Pattern by a Possible Avian Predator, Science, February 1975.
Once it was a Darwinian presupposition. Then it was proved right. Are you beginning to notice a pattern here? Y'know, like how the facts always turn out to fit the theory perfectly in every detail?
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.

This message is a reply to:
 Message 60 by MartinV, posted 09-15-2007 2:15 AM MartinV has replied

Replies to this message:
 Message 65 by MartinV, posted 09-15-2007 3:09 AM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 68 of 241 (422010)
09-15-2007 1:57 PM
Reply to: Message 65 by MartinV
09-15-2007 3:09 AM


Re: Ladybirds and neodarwinian "natural selection"
It depends. Heikertinker did not believe in aposematism and poisionos qualities of ladybirds and all those experiments proving it.
So, one man with a crank theory got results which he interpreted as contradicting every single experiment done on aposematism before or since.
I wonder if by some whilom chance he was right, but I'm not exactly holding my breath.
All those experiments are described in details in his work the link I have given.
Which one?

This message is a reply to:
 Message 65 by MartinV, posted 09-15-2007 3:09 AM MartinV has replied

Replies to this message:
 Message 70 by MartinV, posted 09-15-2007 2:42 PM Dr Adequate has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 75 of 241 (423442)
09-22-2007 5:32 AM
Reply to: Message 72 by MartinV
09-20-2007 1:57 PM


Re: Use of Links
I supposed that Dr.Adeuate can read German.
I can. However, I am unwilling to plough through forty pages of scientific prose in German in order to find out if you have a point.
So far your point seems to be that insectivores are better adapting to eating insects than to eating pork. What you think this proves, I have no idea.

This message is a reply to:
 Message 72 by MartinV, posted 09-20-2007 1:57 PM MartinV has not replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 82 of 241 (424189)
09-26-2007 5:03 AM
Reply to: Message 80 by MartinV
09-26-2007 12:24 AM


Re: Mimicry
You are obviously missing the main point. "Unpalatability" is a concept conceived in selectionists heads to support their explanation of aposematism. No such phenomenon as unpalatability of wasps or ladybirds exists in reality ...
Uh, yes it does.
Pyrazine is indeed unpalatable to birds, and pyrazine odour makes visually conspicuous prey aversive.
That's pyrazine, as in ladybirds.
As for wasps, in reality, they really do sting. They really do. This is kindergarten stuff.

This message is a reply to:
 Message 80 by MartinV, posted 09-26-2007 12:24 AM MartinV has replied

Replies to this message:
 Message 85 by MartinV, posted 09-26-2007 2:06 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 92 of 241 (426189)
10-05-2007 3:54 PM
Reply to: Message 87 by MartinV
09-27-2007 1:14 PM


Re: Mimicry
Wasps defend themselves against things other than birds. They do so by, amongst other things stinging. Stinging is a defence mechanism.
Which part of this don't you understand?

This message is a reply to:
 Message 87 by MartinV, posted 09-27-2007 1:14 PM MartinV has replied

Replies to this message:
 Message 94 by MartinV, posted 10-05-2007 4:06 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 93 of 241 (426190)
10-05-2007 3:57 PM
Reply to: Message 80 by MartinV
09-26-2007 12:24 AM


Re: Mimicry
"Unpalatability" is a concept conceived in selectionists heads to support their explanation of aposematism. No such phenomenon as unpalatability of wasps or ladybirds exists in reality.
Unfortunately for you, saying this won't make all the evidence to the contrary vanish by magic.

This message is a reply to:
 Message 80 by MartinV, posted 09-26-2007 12:24 AM MartinV has not replied

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024