Spider That Builds Its Own Spider Decoys Discovered
wired.com
wired.com
Sure, but what is more interesting is how such a spider would know what itself looks like.
I'd guess that its sculptures started as fairly undefined clumps that served the purpose somewhat well (presumably that's what's built by other "sculpting spiders" that the article mentions?). And then evolution has refined that clump, like it does so well.
Imagine there's a cluster of spiders and a cluster of predators of those spiders. The predators can directly grab the spider, but if it fails and gets caught in the web, the spider wins. The predator is pattern matching on "what looks like a spider."
Maybe a few spider brains create reliable glitches in their webs. Maybe the glitches look enough like not-web where some predators get caught in the web when trying to catch the non-spider. The uneaten spiders-with-web-glitches reproduce and create further glitch making spiders. The predators not caught in the web (i.e. not fooled by the web glitch) also reproduce (n.b. the predators are reproducing glitch-avoiding pattern matching, so we have a glitch-vs-anti-glitch brain race), and some new spiders have more glitchy mutations making bigger anomalies. The anomalies looking more spider like will attract predators, and those spiders won't be eaten as easily. The uneaten spiders can reproduce more glitch-making spiders. The uneaten prey can reproduce more glitch-avoiding prey. The steady state of this model ends up with spiders reproducing themselves so the predator needs more and more advanced web glitch detection. Let this cycle go on for unbelievably long time scales (thousands? tens of thousands? hundreds of thousands? millions of years?), and you have a predator-prey derived "art."
The spider doesn't "know" it's intentionally making decoy spiders. It's just evaluating it's internal tiny spider brain state machine with evolutionarily derived glitches over the past ginormous number of years.
TL;DR - Over years fishermen threw crabs with face-like patterns on their carapaces back into the ocean. Over time this produced crabs with extremely detailed faces, increasing the chances they wouldn't be eaten and could reproduce.
I have absolutely no idea of the time that is necessary for such characteristic to evolve, but I think it's not that much time when talking about insects or arachnids. Evolution is not iterated over time, it happens over generations. And when talking about insects or arachnids, we have a lot of them in a short span of time.
Things like: How do they account for recessive traits? Can something that is recessive become dominant? Can something dominant just disappear (I imagine that it could with mutations happening so much)? Is there a specific animal they use to test these things? Do different traits take longer to evolve towards?
I imagine they use something that reproduces rapidly (fruit flies? fleas?).
On the topic of this spider and how does it know what it looks like...I don't know how much brainpower the spiders have but I know that we have a part of the brain that tracks where our body is (at least in relation to other body parts). Is it possible the spiders have something similar? Can this even be used to make a rough representation of oneself?
I am going to have to google some of these later as I'm now curious.
Probably those spiders are the result of a similar evolutionary process.
http://unionid.missouristate.edu/gallery/L_reeveiana/Reevian...
EDIT: looks like jre beat me to it
Something like this:
1. get bit of leaf. 2. go to center of web. 3. while standing on leaf bits, go down (with G). 4. drop bit of leaf, leaving gap to the left and right. 5. if more than 20 paces from the center. Forget it, relax. 6. goto 1.
With a bit of fiddling I have no doubt you can write a simple program to produce these shapes.
If you find this interesting, check YouTube for termite and wasp nest videos. Incredible!
I think that the spiders that didn't create these decoy structures were selected against in the evolutionary process. The production of decoys could have been genetically engrained into their instinct (via mutation), or, this species really are actually able to recognize itself and create a decoy -- both of these cases would have led to less of them being eaten by predators, hence natural selection.
I can't wait to hear the results of the study after they research it more closely!
Spiders are very smart for their size (up to 80% of their body cavity is brain, and much larger than for insects), but giving them theory of mind is a stretch.
"That guy there wants to eat me. I look like this. If I make a thing that looks like me, he will think it's me and try to eat that, and I'll be safer."
vs. I just love to get bits of leaf and stick them just so!
I'm no expert, but the fact that spiders have 8 eyes suggests to me that they may, indeed, be good at recognizing visual patterns.
http://io9.com/5969515/corvids-the-birds-who-think-like-huma...
And that probably is "know", as in "built into its genes through evolutionary trial and error". It is not likely this is something mothers learn their children, or that they adapt the looks of their decoys within days if researchers let new predators loose (either might be true, but would truly be surprising)
http://blog.perunature.com/2012/12/new-species-of-decoy-spid...
What appears spider-like to a fly, could be dramatically different - I'm imagining the process of trying to count appendages through a compound eye with a fly's brain and in the absence of the cultural system of symbols we use to represent numbers, etc.
See Thomas Nagel's What is it Like to Be a Bat? http://books.google.com/books?id=fBGPBRX3JsQC&pg=PA165#v...
Here are a few of my favorite, more on the philosophical side, quotes from the book:
Insects bring home the uneasy truth that you don't need a big brain to do big
things, and that in turn makes us question how the mind and, dare to say it,
the spirit, are related to the brain. It even makes us question what it means
to be human. What does it mean to have complex behavior? Does it mean you are
smart?
Natural selection can produce what looks uncannily like intelligent thought or
emotion but is no more than the relentless culling of minute variations in genetic
makeup, generation after generation, for millions of years. Not only that, but
insects too have small personalities, with some showing boldness in new situations
and some hanging back with what looks an awful lot like shyness. It's turning out
that we haven't cornered the market on individuality, either.
Insects are starting to answer the question of "What does it take?"—to have a
personality, to learn, to teach others, to change the world around them—with the
humbling and perplexing answer, "Not much." Humbling because they do these things
with brains the size of a pinhead, and perplexing because if that's all it takes,
what does that mean for us, with our gigantic forebrains and exhaustingly long
periods of childhood dependency? The spiders’ webs were crafted around face-height, near the trail
step 1. less-evolved spider builds random clump on web
step 2. spider achieves benefit of scaring off more predators
step 3. spider with clump-building ability becomes dominant species as it outperforms and outcompetes non-talented spiders
step 4. spider with clump-building ability builds less-random clump
step 5. repeat step 2 thru 4 until spider-like clump achieved
my question with this hypothesis is, why does the clump-building behavior end up with something that looks like a spider and not something that would give the spider an even greater evolutionary edge, like say, a tiger's face?
Just my opinion. I guess we don't know for sure. There's probably a way for some biologist to figure that out for certain - would make an interesting postdoc.
It doesn't necessarily have to be appetizing. Any amount of confusion, hesitation, etc. it can cause is potentially beneficial. Even if only one in a thousand predators hesitates or attacks the wrong spot one in a thousand times when it sees a decoy, that's going to have an effect over millions of years.
About the attention-seeking behavior, we can compare it to the same behavior geckos adopt when they find themselves in danger: they start shaking their tails vigorously to attract the attention of the predator to the tail (geckos are known for being able to detach their tails in these cases, and once detached the tail keep shaking vigorously, potentially attracting the predator giving the gecko a chance to escape). In both cases, the spider and the gecko seem to only engage in this behavior once they already have the predator's attention, so trying to escape without shifting the predator's attention to the decoy could actually put the attention on them.
If the decoy becomes too successful, the predator will evolve to have more sophisticated detector, find something else to eat, or become extinct.
Modern heat seeking missiles have fancy multi-frequency heat detectors or even IR CCD cameras with image processing to ignore the flares.
I finished it though because it was fascinating. Reminds me of the birds that have elaborate rituals and when I think of the bug versions they are much less exciting. The spider was 'almost' cute but then I saw some of the other suggested videos and remembered why I don't like them.
What's amazing is there are probably many species of bugs just waiting to be found.