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Parasitic Wasp Reprograms Its Host Spider
Dan writes: "The New York Times has an article about a bizarre Costa Rican spider parasite. This tiny wasp larva forces its host, an orb spider, to do its bidding before killing it. Instead of building a normal round web, the spider spends its last night stringing together a frame. The larva then kills the spider and uses the frame to support its cocoon. The scientist who discovered the behavior still doesn't know how the parasite does it." Since this is an older article, there's probably some more recent information available about this critter.
Embrace and extend.
It would be incredible if the wasp had reordered the spiders DNA or something.
Thanks,
Travis
forkspoon@hotmail.com
The August issue of the National Geographic magazine had a (what I thought to be interesting) article on spiders in general, and this larva in particular.
More information here.
Bush Lies Watch
Here's the original articlea tu reList/august2000/406255.pdf
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http://www.psychiatry.wustl.edu/Resources/Liter
Since the researchers think that it's a response of spiders to chemicals. Here's the famous spiders on drugs experiment.
http://www.cling.gu.se/~cl5pwall/spiders/spider
Some time ago, I saw an interesting documentary on TV about snail parasites (IIRC, the parasite was some kind of worm). The snail gets infected by eating the parasite's eggs which stick to edible plants. The eggs hatch inside the snail, and the parasitic larvae move to the snail's antennae where they start to grow. When they are mature, they somehow modify their hosts' behaviour - normally, the snail would hide from predators during the day. But now it exposes itself to birds, which mistake the swollen, bloated, parasite-containing snail antennae for yummy insects, rip them off and eat them. The snail doesn't survive this for long...
Inside the bird, the parasite lays its eggs and dies. The eggs get spread with the bird droppings, which hopefully fall on snail-edible plants, etc...
Cthulhu fhtagn!
The wasp married the spider.
Political Correctness is doubleplusungood.
Damn, now if I can just do that to Commander Taco, I can make him MY personal gimp instead of JonKatz's personal gimp!
One interesting example of host behavioral modification is in the single-celled protozoan Toxoplasma gondii.
This organism has two different hosts in it's life cycle, cats and rats. An infected cat will shed parasites in its feces which are then picked up by rats. The parasites take up residence in the rat until it is eaten by a cat, completing the life cycle.
The parasite takes up residence in various tissues of the rat, including the brain. Interestingly enough, infected rats show behavioral modifications. They become less cautious and more "curious", and may lose their normal aversion to the scent of cat urine -- thus making them easier prey.
Toxoplasma gondii also frequently infects humans, with some estimates suggesting up to half of the population having been exposed. It is dangerous to human fetuses and individuals with deficient immune systems (such as those with AIDS), but healthly carriers are usually asymptomatic.
It is uncertain whether or not the organism produces behavioral changes in humans, but there have been some suggestions that it might. Toxoplasma gondii link.
Perhaps this is why I compulsively stick my neck out all the time, whitewater kayaking, paragliding, motocross, etc. I hope I don't get eaten by a cat...
Philosophy aside, this could have some real applications. By manipulating basic, instinctual behavior of animals with a chemical application, you could all sorts of things.
For example, in California we have a well known problem with fruit fly infestations. There are two basic ways to deal with them: poison the buggers en masse, or sterilize a batch of males with radiation and release them (apparently, the females will mate only once, so they hook up with the guys shooting blanks and never reproduce - thus eliminating two of the creatures for the price of one). If a chemical could be developed that causes male fruit flies to somehow interrupt their mating behavior (say, do the courtship dance but never consumate the deed) you've essentially combined both techniques. Instead of releasing a few thousand sterile males (an expensive process), you wind up esentially sterilizing any male you expose - potentially many millions.
I just hope Madison Avenue never finds the equivilent formula for human buying behavior. (*GRIN*)
"Prepare for the worst - hope for the best."
Only problem with this is that a *LOT* of research would have to be done before releasing it into the environment. You could affect a lot of other fly species that are very closely related to the fruit fly, but are otherwise harmless to crops.
I'm from Australia and we've learnt our leasons the hard way here. Cane toads are probably our best known stuff up. They were introduced to control another introduced species (a bettle I think) that was eating sugar cane. The Cane toad ended up completely ignore the beetle and eating every native insect it could. Now it's a major pest that is very hard to control.
Don't you have to be one of those to get invited to Davos, World Bank, or IMF meetings? Hell, it's the only demographic that ever made it into the Oval Office!
It's stuff like this that makes the whole idea of evolution seem pretty silly. It would be one thing if the wasp used it's poison as a defense mechanism, but this is not a behavior needed for survival. The wasp could build its cacoon someplace else yet it "just happens" to have this instinct to attack the spider and inject precisely the right chemical, then wait around for it to build the messed up web, then kill the spider and use the ill-formed web for a specific purpose. Seems like pretty intelligent design if you ask me.
That's the wackiness of evolution... it's completely *random* in what it tries out, but very directed in what it keeps. Weird things happen, they work, and so they keep happening.
The difficulty in understanding a particular adaptation is determining the chain of events? Like the question: "How did we evolve Consciousness?", and for ex. a possible answer related to evolution of language and symbolic thought which is given in the book "The Math Gene" which I recently read.
I've found that a person's disbelief in evolution can usually be explained by that person misunderstanding the process of evolution.
For anyone that might think this idea is something far fetched and applies only to esoteric spiders, consider a fairly common disease, rabies. Symptoms in humans include hydrophobia (a fear of water!), and in animals we all know the usual stereotype - aggressive and foaming at the mouth. Talk about mind-altering. Does this add to the ammunition of those that say we don't have a soul, that everything we are is contained between our ears?
I mean, it was really me who chose to eat that enchilada at lunch, right?
Nope, it wasn't you. It was the grasses (wheat) secreting a chemical (starch) in order to use you (humans) as a weapon (agriculture) in their eons-old war against the trees.
------DO NOT WRITE BELOW THIS LINE------
Ummm, they release a LOT (!!) more than a few thousand sterile male fruit flies. They release millions of them (when they release them at all).
I was reprogramming host spiders in z80 assembler through the altair's switch-based input before this upstart wasp thing had evolved wings!
Liberty uber alles.
It seems to me that an "intelligently" designed spider would not have this defect...
So what is it? Is it "proof of a smart creator" that makes a cool wasp, or "proof of a dumb creator" that makes a susceptible spider?
(Personally, I think a smart creator sets the wheels in motion, turns on all the machines, activates the program, and runs behind the scenes.:)
Liberty uber alles.
no, no, no. the reason we exist is...
the earth needs plastic.
Liberty uber alles.
I read about this a while ago. As I recall, researchers confirmed that the change in behavior was caused by chemicals. The added and removed the parasite at different stages of the life cycle. Once it was removed, the spider went back to its normal behavior. They may have even tried just injecting the chemicals, although I don't recall now.
also check out these related spiderweb photos off of the photo index of parasites.
Imagine a Beowulf cluster of those!
It's not just other species of flies that you would have to worry about. Research on Drosophila has turned up countless genes that effect behavior and have analogs in the human genome that act in similar ways. It's more unusual to find a fly gene that doesn't have a human analog that to find one that does.
Vertebrates and Invertebrates have been evolving independently for hundreds of millions of years, yet they still have much in common at the molecular level. A general introduction of behavior-modifying chemicals to the environment could potentially disrupt the behavior of just about any animal in the area.
Also, I see little reason to assume that behavioral poisons would be less expensive than lethal poisons, so where is the advantage in this approach?
Many parasites alter host behavior. A peacock displays his tail to the peahen to indicate the degree to which he is free of parasites.
Even a mosquito will select hosts that have weakened immune systems as indicated by kairomones.
The actual uptake of the parasite's dna into the host's cell (transformation) in controlled by a competence protein which is found in the pheromones of microbes.
The problem with cane toads, is that they can't and don't fly.
Cane beetles (also introduced to Australia) do fly. So the cane toads are pretty useless at killing them.
Instead, they breed enmasse, and are then consumed by both native animals and pets. Cane toads being poisonous, this tends to end the lives of said native animals and pets - the pets are an individual loss and can be coped with, but the native animals dying by eating cane toads is actually threatening the existance of some native species - fresh water crocodiles for example.