Are you sure that the purpose of this mimicry is to attract the attack of the predator toward the wing of the bug so as to protect its main body? This seems a very strange strategy to me and I would rather suggest instead that it is a type of batesian mimicry, wouldn’t you?
Please provide evidence to back up this “exception not the rule” claim.
But you can provide no scientific or technical reason for the skepticism, just your religious pre-conceptions. That won’t cut it in the scientific community.
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I did some research. This particular fruit fly Goniurellia tridens is well known for the blotches on its wings. In some of the subspecies the blotches look like ants or spiders, or just distracting camouflage.
Ants spiders or wishful thinking
The patterns come in various degrees of similarity to other insects. No matter what the pattern they all help provide the insect with a better chance at survival and reproduction.
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Research; don’t ask questions without it.
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No, I’m not sure of that. It is however an observed phenomenon in numerous flying insects that spots near the tips of their wings, that stand out when contrasted to the main body, which is somewhat better camouflaged and inconspicuous compared to the wings, works to divert predator attacks towards the wing tips and away from the head and thorax. I linked an article with an experimental demonstration of the phenomenon in butterflies up earlier in this thread.
What stands out to me here with the fly is the fact that the image on the wings is near the tip of the wings, with the head of the pictured insect very close to the tip. And the wings seem almost completely transparent on the right background. As they write in the article I linked, when predators attack flying insects like flies and butterflies, they will normally aim for the head or thorax. So it is quite plausible a predator will aim for the head or thorax of the percieved image on the wings, and so entirely miss the body of the real fly. The fly itself is quite pale in comparison to the dark image on the wings, and the head of the picture is almost entirely black. My guess is, without actually knowing, that these flies live on pale/bright-colored backgrounds that make the images on their wings stand out strongly.
It is of course still possible this is just another example of Batesian mimicry, in which case the image on the wings might be some species of wasp? We’d have to know a lot more about the environment where these flies live to say.
To Faizal’s point earlier about variations in this pattern, here are some of the wing patterns in closely related species:
It is entirely conceivable the pattern could have evolved incrementally from a pattern such as this:
There is apparently an incredible amount of diversity in these wing patterns among closely related flies:
http://cjai.biologicalsurvey.ca/jmhn_15/Galleries/TephritidaeWingPlates/wingalbum/wings.html
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More examples of wing pattern diversity in fruit flies.
Seems to me there’s a good case to be made for the gradual evolution of the image of a fly through various stages similar to these, by natural selection.
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Thanks, @Giltil, for asking a question which prompted others to provide me with a lot of new things I didn’t know. I hope you enjoyed it as much as I have!
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Says who???
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Seems like an open question is if the fly image on those wings was atypically accurate, not reflecting genetics, just phenotypic variability in this particular fly.
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I think that this is a great example of how things can seem to be quite intuitive, but really are not. I remember when I first visited here some time ago, that’s one of the things that @swamidass and @T_aquaticus said. These patterns that look like flies, for instance, seem to us to clearly be images of flies, but they are just adaptations that have occurred over time. They may serve to look like flies, and, as such, protect or offer some other advantage to the animal who displays them. But, this is also what I was speaking of (or asking about) in the OP… The bug that looks like a torn leaf seems to have been designed to look like a torn leaf. In actuality, its pattern merely developed over time and ended up to look like a torn leaf.
And furthermore, will this pattern end up to be a huge advantage over time and become more prevalent among this species?
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The first word of the title is “Origin.” Do you not understand that English word?
They aren’t that new. You’re also ignoring the primary mechanism for light/dark changes. Why is that?
How much variation is already present in the population? You aren’t assuming that there is no existing variation between individuals, are you? That would be ridiculous.
You are making that false assumption. Why?
No, we don’t.
False. They hypothesize that it evolved from a transposon and tested the hypothesis. That’s science. You should consider trying it.
Why are you ignoring existing variation?
Why would we assume that?
I’m not seeing any interest in science from you.
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I am too. I would hypothesize that it was only mostly Darwinian. I’m confident there would have been plenty of neutral evolution involved.
Have you forgotten about that?
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Yes, I enjoyed it. What a fascinating topic!
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IIRC this has actually been observed w.r.t. the eye-spots on butterfly and moth wings.
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i think that its a generous assumption that base on what we see in the real world. for instance: we have billions of people in the wrold. and we never seen someone who evolved say a new organ part like a part of a wing or a new part of an eye etc. so the chance to get a new anatomical part is probably lower than few billions. at least from what we can see in the real wrold. do you agree or disagree?
sorry but im not sure what is your argument here. maybe i miss something so please explain again your point.
we never observed a complex biological system evolving in front of our eyes of course.
i think that you are mixing between genetic similarity and genetic identity. as far as i remember if the sequence (between two people) is a bit different then you cant use it at court anymore. even that all people share a common descent. also: have you forgot about convergent genetic evolution?
that is the problem: you cant do that if the new mutation is neutral. in the dice case you choose your goal and ignore all the other results. this cant happen in nature.
i do talking about that. how such a system that can control color change evolved?
You did not understand the analogy. It is merely to demonstrate that the odds of any particular combination of numbers is much more easily arrived at if the process can be cumulative rather than simultaneous.
I would like you to try explain why this could not work if the mutation was neutral.
There are times when conclusions are intuitive, but are still wrong. The point being, human intuition is fallible. As I often say, we have the scientific method because human intuition can’t always be trusted.
The analogy I often use is water. Rain lands randomly across the landscape, but it consistently finds flows to the lowest elevation without needing guiding from an intelligence. Evolution is much the same where species move towards a more fit phenotype. Every landscape will have a different water drainage pattern, and each species will find a different route towards better fitness. Camouflage is such a powerful adaptation that we see a lot of different paths, and given the gravitational pull towards better fitness it is inevitable that some paths will lead to the adaptations we see.
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A new anatomical part is not a new protein. Chimps and humans differ by 40 million or so mutations, and it is obvious that most of those mutations are not going to affect fitness in any meaningful way. This means that the number of mutations that explains the differences between our species is in the 10’s of millions, and perhaps fewer than that. It didn’t take billions of mutations to produce the differences between us.
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We have observed HGT between organisms resulting in a sequence in one organism resembling the sequence in another organism, which is what is being claimed happened here.
No, I haven’t forgotten about convergence, what makes you think that? There are exceptions to just about every rule in biology, but generally speaking (especially when dealing with large sets of sequences), we can take sequence similarity as an indicator of relatedness.
When we find a symbiotic prokaryote living in very close association with cephalopods, and this prokaryote has a transposon in its genome that has a high sequence similarity to parts of a cephalopod-specific gene, it’s perfectly reasonable to conclude that this sequence was transferred from the prokaryote to the cephalopod.
Creationists would probably be fine with this scenario if it wasn’t for the fact that the sequence in cephalopods is functional, as you have an a priori belief that natural processes can’t create new functions, therefore you have no choice but to deny a reasonable inference.
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No one person has ever observed a mature redwood tree grow all the way from a seed. Does that mean redwood trees were POOFED into existence?
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