หมายเหตุ: การถอดเสียงไม่สมบูรณ์ร้อยเปอร์เซนต์ บางส่วนที่ไม่แน่ใจได้แสดงเป็นตัวสีเทา ผู้รู้สามารถแนะนำเพิ่มเติมในส่วนนี้หรือส่วนอื่นๆ ได้
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And one insect has taken that to the extreme, twisting its venom for a diabolical purpose. It's like something out of science fiction, turning another animal into a zombie. These … are the emerald jewel wasp. In this lab at the University of California, Riverside, researchers want to know how the wasp's chemical arsenal evolved to completely control her host. Science first became fascinating with venom because they represent a kind of chemical warfare. Jewel wasp are parasitoid. They paralyze her prey so her offspring can live of them. After decades of research, scientists are beginning to understand the secret of parasitoid venom. Female to battle with a host to its plentiful widely avaiable and six times her size, … the American Cockroach. Researcher Chris Banks has devised a genious method to experiment with the wasp venomous attack. We're going to put a wasp and a cockroach into this area right here and let them interact. Involving put in glass barrel here and this will serve as make chip burrow for the wasp. An unexpecting host is first introduced into the arena. The roach is unaccustomed to threats from smaller animal. The stage for the battle is set and the wasp is released. As soon as the jewel wasp senses a host, she was surprised her prey and used that brief moment to her advantage. She attacks. The wasp first sting is brilliantly stick inject just enough to disarm the roach. The first time it stings into the central nervous system and caused a temporay paralysis of the front legs. Venom hits the roach its nervous system in between its front legs, breifly paralyzing them. This allowed the wasp to do a second much more precise sting into the brain. The wasp twists its body around the roach so it can sting into its brain and inject the zombifying mixture. The roach is breathing slow. It makes no move to escape. This brain's sting causes a dramatic behavioral changing in the cockroach, basically turning into a zombie. Wasp' venom is precisely engineered to shut down signal carried by a key brain chemical called Dopamine. In human and other animals Dopamine is a naturally occurring chemical messenger in the brain. It regulates movement and sensation. With its Dopamine knocked out the roach cannot move freely or escape. Millions of years of evolution have refined this wasp's ability to hit her target and disrupt Dopamine with the precision of microscopic brain surgery. This remarkable skill isn't learnt, it's inherited, hard wired into each wasp. They are natural born nerve surgeons. To regain some of the energy the wasp has lost to her sting, she clips the end of the roach antennae and take a drink of roach' blood. Refueled the wasp lead her zombie cargo to her burrow. But if the wasp can target her venom so well, why doesn't she simply deliver a dead blow? Venom is used for defense; venom is used for feeding; but parasitoid do it for somthing totally different. They actually use it for reproduction. Inside the burrow the wasp lays her egg on a roach. With survival of her offspring is stake, the wasp' precision now make sense. Her young depend on perfect execution of her sting. Now the wasp barricades the defenseless roach inside the burrow. For more than a week the wasp venom continue to keep the roach common complaisance, even if its newly hatched larva start to eat it alive. From that single egg, a larvae hatched. And ... after three days it drills a hole in the leg of the cockroach, And … get the nutrition from the blood system of the still zombified cockroach. And now for natural selection test, too little or poorly aim venom and the roach could escape. Too much venom and it will immediately die, destroying the wasp offspring fresh food source. Here we see the larva actually starting to burrow into the croaroach itself. It will crawl inside, and continue to feed out of the internal organ of the cockroach. After another couple of days it will enter a coccoon. If all goes accroding to plan, six week from the first sting a new adult jewel wasp emerges from the hollowed out dead roach. The new wasp is ready to carry on its vicious legacy. If she is a female her venom is ready to provide for a new generation. The wasp is a very specific hunter, it only hunts cockroaches, and only cockroaches of this species. So every wasp that was born from a pupa that was … that emerged from a dead cockroach, had their mother that knew exactly what she was doing. So in that way the wasps are getting better and better and better at this. The only way that the wasp can subdue a croroach is because it knows its prey so well and it can inject the venom right where it needs to go, and have exactly effect the wasp's need. |
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