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Author Topic:   Mimicry: Please help me understand how
Modulous
Member (Idle past 418 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 106 of 241 (427076)
10-09-2007 4:34 PM
Reply to: Message 105 by MartinV
10-09-2007 3:28 PM


Heikertinger
Heikertinger is also mentioned in the article as "source" but oddly enough no one of his idea has been dealt or mentioned in the article!

It really shows that you haven't read it, or even bothered to do a search:

quote:
An obvious tack is to deny that mimicry can possibly be of poor quality, and hence to claim that poor ‘mimics’ simply are not mimics at all. Before the advent of more rigorous quantitative testing of mimicry theory by the Browers and others, there were several who claimed that because some mimics were eaten by some predators sometimes, this meant that mimicry did not ‘work’, and hence was invalid as a theory (McAtee, 1932; Heikertinger, 1918, 1936, 1954). It is a simple step then to accept perfect mimicry as a valid concept, but to deny any other kind of resemblance as mimetic: for example, Glumac (1962) and Drees (1997) thought there were no mimics among syrphids except for those with elongated antennae (even bumblebee mimics, which they attributed to convergent requirements of thermoregulation). Waldbauer and his colleagues (see Waldbauer, 1988; Maier, 1978) simply ignored poor mimics altogether because it was impossible to determine whether they were really mimics or not.

However, denial of the reality of mimicry in these syrphids has not been credible since Mostler’s (1935) detailed and large-scale experiments on learning in naïve and experienced insectivorous birds. Single birds were free to fly in a large windowed room with naturalistic perches, and models and mimics were released alive into the back of the room, usually to fly directly to the window: Mostler recorded the subsequent behaviour of the birds. He divided his study into two parts: the first was concened with the beginning and the end points of the learning of birds, i.e. the responses of young naïve birds and of old experienced birds to models and mimics; the second part investigated the learning process itself. Although he did not plot or hardly even analyse his data, the great value of his work is not just that it was the first well-designed large-scale experimental approach to testing the theory of mimicry, but also that he obtained comparable data on all three hymenopteran models and their hoverfly mimics. These established beyond doubt that the colour patterns of all the syrphids he used did give substantial protection from predation


The section I bolded (and the ones before) seems to be an accurate summing up of your argument, and since you are arguing based on Heikertinger and McAtee I assume it is an accurate summing up of their argument too. Heikertinger was mentioned, and his idea was dealt with.

But the question is like this - if there are species, that are more cryptic like bees or species in polistinae - why are they not protected by "aposematism"? They do not need it? But vespinae need it?

You could ask the same question of any flying insect - why don't they all have aposematism? Evidently it is not required that a flying insect evolves aposematism, but it can happen.

I am afraid the research done on 80.000 contents of stomach birds showed clearly that wasps are eaten by birds and it were these facts that persuaded McAtee that aposematism of birds is ineffective.

I'm not claiming that birds do not eat wasps.

Do not forget there are 600 species of moth's family that possess yellow-black striped patterns and we should consider probably also those species as mimics.

There are also dragonflies with black-yellow patterns etc...

Maybe yellow-black patterns are so common in insect realm that we shouldn't consider it as mimicry especially when results of experiments of protective value of "model" are so ambiguous and often contradicting each other.

Yes - yellow/black is certainly a possible colour an insect might possess. It doesn't have to serve as aposematism in all cases - I really haven't looked. I have not seen evidence that the experiments regarding protective value were ambiguous. Field observation and experiments have clearly shown that some birds avoid mimics after they have had a negative experience with a noxious model.


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 Message 105 by MartinV, posted 10-09-2007 3:28 PM MartinV has responded

Replies to this message:
 Message 107 by MartinV, posted 10-10-2007 2:59 PM Modulous has responded

  
MartinV 
Suspended Member (Idle past 4142 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 107 of 241 (427234)
10-10-2007 2:59 PM
Reply to: Message 106 by Modulous
10-09-2007 4:34 PM


Re: Heikertinger

The section I bolded (and the ones before) seems to be an accurate summing up of your argument, and since you are arguing based on Heikertinger and McAtee I assume it is an accurate summing up of their argument too. Heikertinger was mentioned, and his idea was dealt with.

I forget it was there. Anyway on my reading Heikertinger and McAtee were of opinion that wasps as models are eaten and they consequently didn't solve the problem if their mimics are eaten. If the models are eaten there is no survival advantage for some species to look like models.

It could be taken for granted that whatever aposematic or "poisonous" species you find there are almost for sure predators specialised on it. See many bee-eaters etc.

quote:

Rainbow Bee-eaters eat insects, mainly catching bees and wasps, as well as dragonflies, beetles, butterflies and moths. They catch flying insects on the wing and carry them back to a perch to beat them against it before swallowing them. Bees and wasps are rubbed against the perch to remove the stings and venom glands.

Such predators wellcome aposematism of wasps I dare say - they can see wasps from great distance.


You could ask the same question of any flying insect - why don't they all have aposematism? Evidently it is not required that a flying insect evolves aposematism, but it can happen.

As far as I can judge one of the most used explanation of aposematism is that it represents a warning - be carefull I am dangerous and remember me! I don't see a point to be dangerous and not to represent it as in the case of many species of wasps, bees, bumble-bees etc...
Natural selection in these cases didn't carry its work toward warning coloration or what?


Field observation and experiments have clearly shown that some birds avoid mimics after they have had a negative experience with a noxious model.

It depends. Other experimets show that after few hours the stinged birds eat wasps as if nothing happened.


Yes - yellow/black is certainly a possible colour an insect might possess. It doesn't have to serve as aposematism in all cases - I really haven't looked.

Yes. Scientists should perhaps reconsider "imperfect mimicry" of those 6.000 species of hoverflies. Maybe we are not facing mimicry but some kind of convergent evolution that has nothing to do with mimicry.


This message is a reply to:
 Message 106 by Modulous, posted 10-09-2007 4:34 PM Modulous has responded

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Modulous
Member (Idle past 418 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 108 of 241 (427239)
10-10-2007 3:15 PM
Reply to: Message 107 by MartinV
10-10-2007 2:59 PM


Re: Heikertinger
It could be taken for granted that whatever aposematic or "poisonous" species you find there are almost for sure predators specialised on it. See many bee-eaters etc.

Such predators wellcome aposematism of wasps I dare say - they can see wasps from great distance.

No doubt. Do you suggest that the penalty for aposematism outweighs or balances out its benefits? Do you have any evidence for this?

As far as I can judge one of the most used explanation of aposematism is that it represents a warning - be carefull I am dangerous and remember me! I don't see a point to be dangerous and not to represent it as in the case of many species of wasps, bees, bumble-bees etc...

Not just dangerous but also distasteful. If you are dangerous you don't have to advertise it. Wasps that sting but don't warn about their bad taste can still use their sting to subdue prey or what have you. Not all wasps have stings as far as I am aware too.

It depends. Other experimets show that after few hours the stinged birds eat wasps as if nothing happened.

Right, but in total the data shows that some birds avoid eating some mimics after they have eaten a noxious model.

Yes. Scientists should perhaps reconsider "imperfect mimicry" of those 6.000 species of hoverflies. Maybe we are not facing mimicry but some kind of convergent evolution that has nothing to do with mimicry.

If there is reason to conclude that, then so be it.


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garyl43
Junior Member (Idle past 4250 days)
Posts: 6
From: Moab, UT
Joined: 10-18-2007


Message 109 of 241 (429183)
10-18-2007 6:37 PM
Reply to: Message 1 by Lampropeltis
07-14-2007 3:04 PM


Hi all! New to the forum here. I just wanted to add a bit to this post. I've always been fascinated with mimicry in nature, but the answer always seems to be simply "millions of years of evolution". I have a few questions that never seem to be answered:

(1) Why the need for evolution if the plant, insect or animal was able to survive and reproduce just fine for millions of years before it was able to mimic anything else?

(2) Why would a living organism actually make it's survival totally dependant on 1 other species to reproduce, like this orchid: https://www.youtube.com/watch?v=-h8I3cqpgnA ? Seems to me it would diversify as much as possible to increase it's chances of survival according to evolution.

(3) How does a plant know the shape, size, geometry and color of the female wasp and the chemical makeup of it's pheromones since it can't feel the shape, see or smell the female wasp? Heck, how does it even know that wasps exist?

(4) How does a species then morph itself into a copy of whatever it is it "thinks" it needs to be (seeing that plants don't think I thought :))? The wasp in this case has nothing to gain except a sex toy, so It does not need the orchid to survive. Hence the plant seems to be doing the thinking, seeing, feeling, measuring and the straight from sci-fi morphing.

(5) How does an insect know that birds will not eat bird droppings?

Could this be purely by accident or is it an example of two species designed together (and a good sense of humor :) )?

Edited by garyl43, : No reason given.


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Chiroptera
Member
Posts: 6810
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.5


Message 110 of 241 (429186)
10-18-2007 6:48 PM
Reply to: Message 109 by garyl43
10-18-2007 6:37 PM


Hi, gary, and welcome to EvC.

Why the need for evolution if the plant, insect or animal was able to survive and reproduce just fine for millions of years before it was able to mimic anything else?

The issue isn't being able to survive and reproduce just fine. The issue is being more likely to survive and reproduce. Consider a population of a certain species of beetles. If those who look ever so slightly more like Dick Cheney happen to have a better chance of surviving and reproducing than the ones who don't look as much like Dick Cheney, then the next generation of beetles will have more individuals that look ever so slightly more than Dick Cheney.

-

Why would a living organism actually make it's survival totally dependant on 1 other species to reproduce....

Not the topic of this thread.

-

How does a plant know the shape, size, geometry and color of the female wasp and the chemical makeup of it's pheromones since it can't feel the shape, see or smell the female wasp? Heck, how does it even know that wasps exist?

It doesn't. Just that the particular plants that happen to look or smell more like a wasp will produce more offspring than those who don't, so in the next generation there will be more plants that look or smell slightly more like a wasp.

-

How does a species then morph itself into a copy of whatever it is it "thinks" it needs to be....

The species doesn't "morph itself". In one generation, some will look more like a wasp, others will look less. If the ones who look more like a wasp produce more offspring, then the next generation will have more individuals that look more like wasps. After a few generations, the ones that look more like wasps will outnumber those that don't. As new variations in features arise, some will look even more like wasps -- if those produce more offspring, then the next few generations will see this population look even more like wasps. And so forth.

-

How does the insect know that birds will not eat bird droppings?

They don't. It just happens that those individuals that look more like bird droppings will be eaten less than those who don't -- and so will produce more offspring that, presumably, will inherit those features that made the parents look somewhat like bird droppings.


In many respects, the Bible was the world's first Wikipedia article. -- Doug Brown (quoted by Carlin Romano in The Chronicle Review)

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Dr Adequate
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Posts: 16107
Joined: 07-20-2006
Member Rating: 7.3


Message 111 of 241 (429188)
10-18-2007 6:51 PM
Reply to: Message 109 by garyl43
10-18-2007 6:37 PM


Hi, welcome to the forums.

You seem to be under the impression that evolution is something achieved by organisms by an effort of will.

It is not.

A simplified version of the theory of evolution would be "random mutation and natural selection". There is more to it than that, but start there. Your local library will have a book on the subject suitable for beginners. Do have a look, it's fascinating.


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garyl43
Junior Member (Idle past 4250 days)
Posts: 6
From: Moab, UT
Joined: 10-18-2007


Message 112 of 241 (429189)
10-18-2007 7:08 PM
Reply to: Message 111 by Dr Adequate
10-18-2007 6:51 PM


No, I completely understand natural selection. But this is specific stuff here. How did the orchid survive before it had the perfect mechanism to match this specific wasp? Any incremental change would render it useless, If it didn't have the pheromones? wouldn't work. No adhesive on the pollen? wouldn't work etc.. In order for it to reproduce it had to have all this right the first time or it would have simply died out.

Edited by garyl43, : No reason given.

Edited by garyl43, : No reason given.


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Dr Adequate
Member
Posts: 16107
Joined: 07-20-2006
Member Rating: 7.3


Message 113 of 241 (429195)
10-18-2007 7:48 PM
Reply to: Message 112 by garyl43
10-18-2007 7:08 PM


No, I completely understand natural selection.

So when you asked "How does a plant know ...", et cetera, you were just pretending to be ignorant?

How did the orchid survive before it had the perfect mechanism to match this specific wasp? Any incremental change would render it useless, If it didn't have the pheromones? wouldn't work. No adhesive on the pollen? wouldn't work etc.. In order for it to reproduce it had to have all this right the first time or it would have simply died out.

I might have a crack at answering those questions, but first I want your assurance that you are genuinely an ignoramus, rather than just pretending to be one for rhetorical effect.


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ringo
Member
Posts: 17519
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Message 114 of 241 (429196)
10-18-2007 7:48 PM
Reply to: Message 112 by garyl43
10-18-2007 7:08 PM


garyl43 writes:

How did the orchid survive before it had the perfect mechanism to match this specific wasp?

Imperfectly.


“Faith moves mountains, but only knowledge moves them to the right place”
-- Joseph Goebbels
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Modulous
Member (Idle past 418 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 115 of 241 (429197)
10-18-2007 7:48 PM
Reply to: Message 112 by garyl43
10-18-2007 7:08 PM


How did the orchid survive before it had the perfect mechanism to match this specific wasp?
...
In order for it to reproduce it had to have all this right the first time or it would have simply died out.

Other orchids survive just fine without this mechanism.


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garyl43
Junior Member (Idle past 4250 days)
Posts: 6
From: Moab, UT
Joined: 10-18-2007


Message 116 of 241 (429199)
10-18-2007 7:55 PM
Reply to: Message 115 by Modulous
10-18-2007 7:48 PM


That's one of my points Modulous. There is no need for this kind of complexity.

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Chiroptera
Member
Posts: 6810
From: Oklahoma
Joined: 09-28-2003
Member Rating: 4.5


Message 117 of 241 (429201)
10-18-2007 7:59 PM
Reply to: Message 116 by garyl43
10-18-2007 7:55 PM


Oops.
Huh. That's not what you said:

In order for it to reproduce it had to have all this right the first time or it would have simply died out.


In many respects, the Bible was the world's first Wikipedia article. -- Doug Brown (quoted by Carlin Romano in The Chronicle Review)

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jar
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Posts: 31612
From: Texas!!
Joined: 04-20-2004
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Message 118 of 241 (429202)
10-18-2007 8:06 PM
Reply to: Message 117 by Chiroptera
10-18-2007 7:59 PM


Re: Oops.
So funny. Another Type 3 nubee.

You would think there might be at least one Type 2b poster somewhere?


Aslan is not a Tame Lion

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Dr Adequate
Member
Posts: 16107
Joined: 07-20-2006
Member Rating: 7.3


Message 119 of 241 (429206)
10-18-2007 8:14 PM
Reply to: Message 116 by garyl43
10-18-2007 7:55 PM


That's one of my points Modulous. There is no need for this kind of complexity.

Yeah, God really screwed up there, didn't he?

Of all the funny creationist arguments, I think the Argument From Undesign has to be my fave.


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Modulous
Member (Idle past 418 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 120 of 241 (429211)
10-18-2007 8:45 PM
Reply to: Message 116 by garyl43
10-18-2007 7:55 PM


That's one of my points Modulous. There is no need for this kind of complexity.

No, there isn't. There is no need for the earth to exist, for life to exist, or for life to look the way it does.

But there is an explanation for biodiversity, including mimics.


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