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grue

This is the scariest thing I've ever read in my entire life *SCIENCE*

By grue, in The Bonfire

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grue    1

grue
http://loom.corante.com/archives/2006/02/02/the_wisdom_of_parasites.php


February 02, 2006
The Wisdom of Parasites

Posted by Carl Zimmer

I collect tales of parasites the way some people collect Star Trek plates. And having filled an entire book with them, I thought I had pretty much collected the whole set. But until now I had somehow missed the gruesome glory that is a wasp named Ampulex compressa.

As an adult, Ampulex compressa seems like your normal wasp, buzzing about and mating. But things get weird when it's time for a female to lay an egg. She finds a cockroach to make her egg's host, and proceeds to deliver two precise stings. The first she delivers to the roach's mid-section, causing its front legs buckle. The brief paralysis caused by the first sting gives the wasp the luxury of time to deliver a more precise sting to the head.

The wasp slips her stinger through the roach's exoskeleton and directly into its brain. She apparently use ssensors along the sides of the stinger to guide it through the brain, a bit like a surgeon snaking his way to an appendix with a laparoscope. She continues to probe the roach's brain until she reaches one particular spot that appears to control the escape reflex. She injects a second venom that influences these neurons in such a way that the escape reflex disappears.

From the outside, the effect is surreal. The wasp does not paralyze the cockroach. In fact, the roach is able to lift up its front legs again and walk. But now it cannot move of its own accord. The wasp takes hold of one of the roach's antennae and leads it--in the words of Israeli scientists who study Ampulex--like a dog on a leash.

The zombie roach crawls where its master leads, which turns out to be the wasp's burrow. The roach creeps obediently into the burrow and sits there quietly, while the wasp plugs up the burrow with pebbles. Now the wasp turns to the roach once more and lays an egg on its underside. The roach does not resist. The egg hatches, and the larva chews a hole in the side of the roach. In it goes.

The larva grows inside the roach, devouring the organs of its host, for about eight days. It is then ready to weave itself a cocoon--which it makes within the roach as well. After four more weeks, the wasp grows to an adult. It breaks out of its cocoon, and out of the roach as well. Seeing a full-grown wasp crawl out of a roach suddenly makes those Alien movies look pretty derivative.

Ampulex%20emerging.jpg

I find this wasp fascinating for a lot of reasons. For one thing, it represents an evolutionary transition. Over and over again, free-living organisms have become parasites, adapting to hosts with exquisite precision. If you consider a full-blown parasite, it can be hard to conceive of how it could have evolved from anything else. Ampulex offers some clues, because it exists in between the free-living and parasitic worlds.

Amuplex is not technically a parasite, but something known as an exoparasitoid. In other words, a free-living adult lays an egg outside a host, and then the larva crawls into the host. One could easily imagine the ancestors of Ampulex as wasps that laid their eggs near dead insects--as some species do today. These corpse-feeding ancestors then evolved into wasps that attacked living hosts. Likewise, it's not hard to envision an Ampulex-like wasp evolving into full-blown parasitoids that inject their eggs directly into their hosts, as many species do today.

And then there's the sting. Ampulex does not want to kill cockroaches. It doesn't even want to paralyze them the way spiders and snakes do, since it is too small to drag a big paralyzed roach into its burrow. So instead it just delicately retools the roach's neural network to take away its motivation. Its venom does more than make roaches zombies. It also alters their metabolism, so that their intake of oxygen drops by a third. The Israeli researchers found that they could also drop oxygen consumption in cockroaches by injecting paralyzing drugs or by removing the neurons that the wasps disable with their sting. But they can manage only a crude imitation; the manipulated cockroaches quickly dehydrated and were dead within six days. The wasp venom somehow puts the roaches into suspended animation while keeping them in good health, even as a wasp larva is devouring it from the inside

Scientists don't yet understand how Ampulex manages either of these feats. Part of the reason for their ignorance is the fact that scientists have much left to learn about nervous systems and metabolism. But millions of years of natural selection has allowed Ampulex to reverse engineer its host. We would do well to follow its lead, and gain the wisdom of parasites.


:S:S:S:S:S:S:S:S:o:o:o:o

I'm pretty sure I'm gonna follow Howard Hughes' lead. ANyone have some tissue boxes and glass jars? B|
cavete terrae.

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livendive    8

livendive
Quote

Not new here in america happens every 4 years election time they wash out brain and make us do things we don't want to all the time



Wow...I mean WOW! This is one of the last threads I'd have expected to see take a Speaker's Corner-esque turn after only 3 posts! :S:D

Blues,
Dave
"I AM A PROFESSIONAL EXTREME ATHLETE!"
(drink Mountain Dew)

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micro    0

micro
omg. that just creeps me out. i'm going to have nightmares now of a big ampulex wasp injecting the base of my skull w/ it's stinger and leading me around my house, making me murder my children, then it'll fly away, framing me for their deaths. and i'll fry in the electric chair for it.

thanks grue. thanks alot.

I miss Lee.
And JP.
And Chris. And...

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Viking    0

Viking
holyshit that is the coolest bug i'v ever seen!!! as long as they don't get big and start driving humans around into caves and shit.
I swear you must have footprints on the back of your helmet - chicagoskydiver
My God has a bigger dick than your god -George Carlin

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BillyVance    34

BillyVance
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Ok... that actually made me sick to my stomach. Insects are just gross :|



How about this, a female praying mantis, after mating with a male, will then bite his head off. :|

"Hi honey, I'm home! What the f---"CHOMP

:D
"Mediocre people don't like high achievers, and high achievers don't like mediocre people." - SIX TIME National Champion coach Nick Saban

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nessvegas    0

nessvegas
How about this, a female praying mantis, after mating with a male, will then bite his head off. :|

"Hi honey, I'm home! What the f---"CHOMP

:D




How is that any different than my ex-wife? :S[:/]

_________________________________________
I married the right one......it just took me 2 times!

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BillyVance    34

BillyVance
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How about this, a female praying mantis, after mating with a male, will then bite his head off. :|

"Hi honey, I'm home! What the f---"CHOMP

:D




How is that any different than my ex-wife? :S[:/]



Or my current and very pregnant one... :S
"Mediocre people don't like high achievers, and high achievers don't like mediocre people." - SIX TIME National Champion coach Nick Saban

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Tink1717    2

Tink1717
Yeah, cool and viciously predatory at the same time.

I wonder how the IDiots, who deny evolution, would explain how this is NOT an evolved behavior.
Skydivers don't knock on Death's door. They ring the bell and runaway... It really pisses him off.
-The World Famous Tink. (I never heard of you either!!)
AA #2069 ASA#33 POPS#8808 Swooo 1717

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