Zombie Cockroaches and their Wasp masters

[apothecary]

Thought you insect heads would like this.

http://loom.corante.com/archives/2006/02/0...f_parasites.php

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.

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.

[devance]

"The wasp takes hold of one of the roach's antennae and leads it"

"We would do well to follow its lead, and gain the wisdom of parasites."

Wouldn't we only be gaining the wisdom of the zombie cockroaches if we followed the lead of the wasp.

With all the bedbug epidemics world wide we might already have gained such. The bedbugs might somehow be leading us to the hotel rooms to be feasted upon.

I not being lead to any hotel room.

[wandjina]

wasps are so interesting, thanks for that apo...apparently they got the idea for the 'xenomorphs' of the Alien movies from the life cycle of certain species of wasp. another animal that 'zombifies' its host is a kind of parasitic worm (fluke) called a trematode.

The fluke Leucochloridium paradoxum uses the snail Succinea for part of it weird lifecycle which has two hosts: a bird and a snail.

Birds have the fluke eggs in their faeces, which falls on leaves and is eaten by the snail. The eggs then hatch within the snails digestive system, the larval flukes eventually moving to the snails tentacles (what are often referred to as antennae or eye stalks).

Anyone who has ever seen footage of a parasitised succinea will know how peculiar this looks. The effect of the parasitisation is, firstly, that the snail cannot withdraw its tentacles. The snails behaviour is also altered, and rather than hanging out in damp, moist environs, it moves to exposed sunny spots high on plants.

The fluke also causes the tentacles to rhythmically pulse, and they become swollen and colourfully banded. This of course draws the attention of birds, who may eat only the tentacles allowing the snail to survive and grow new ones (more often, the poor little mollusc is no more). The flukes, on the other hand, reach sexual maturity in the birds digestive tract...the eggs later pooed out for the cycle to begin again. Bizarre.

here's some before and after shots of the snail:

[AndyAmine.]

I love the 2nd photo, they actually end up in the snails eye stalks, its freaky to see it on film because they pulaste back and forth every 1/5 a second.

[Benzito]

Argh! This is all too weird.

[devance]

http://www.livescience.com/scienceoffictio...echnovelgy.html

I think common hygene is the way to go without targeting any particular mammal.

A animals health is directly a abilility to ward off parasites and infections so whos better than regular vet checkup.

Dogs also can carry a nasty tapeworm, of course eating their feceaes is necessary, a habit I strongly recommend should not be done.

Basically it loses track to where it going as its not in the proper host and wind up in the human brain.

I took a parasitology class, look up fire worm, Jimmy Carter is concerned about this as just drinking pond water is the best way to get strange but easyly treatable water borne parasite...

[Benzito]

Meh.

I explore stormwater drains under Sydney, and I don't have any bizarre parasites that I am yet aware of.

Seriously, just live your life, try to have some basic hygiene and look after your body.

A healthy body will resist foreign intrusion much better than an unhealthy one.

You could live your life in a bubble, but then you're just protecting yourself from fun.

[devance]

http://www.livescience.com/scienceoffictio...echnovelgy.html

I think common hygene is the way to go without targeting any particular mammal.

A animals health is directly a abilility to ward off parasites and infections so whos better than regular vet checkup.

Dogs also can carry a nasty tapeworm, of course eating their feceaes is necessary, a habit I strongly recommend should not be done.

Basically it loses track to where it going as its not in the proper host and wind up in the human brain.

I took a parasitology class, look up fire worm, Jimmy Carter is concerned about this as just drinking pond water is the best way to get strange but easyly treatable water borne parasite...

I am big fan of the TV series Invasion aboutv U.S. swamp pod people but its a surprising sort soup opera way.

[Rev]

Cook your meat well - esp game or roadkill ;)

wash your hands and clean doorknobs

dont eat wild watercress

Dont let farm dogs lick your face or your kids

dont drink sydney water ;)

that should keep you pretty safe in Australia

we dont have much here

Overseas id avoid pork and chew betelnut (WOWO lime)

and where deer live

use insect repellant and nets and avoid sleeping in proximity to jungle or swamps

wear covered shoes

only swim in clean running water or the sea

Edited February 11, 2006 by Rev

[devance]

We report the first case in Australia of liver fluke infection (fasciolosis) in a patient with no history of farm or livestock contact. She probably acquired the disease from eating watercress purchased at a Melbourne market four to five months before symptom onset.

http://www.mja.com.au/public/issues/178_05...30303_fm-2.html

http://abc.net.au/science/news/stories/s697096.htm

Might have a new profession Rev.

[devance]

Fruit bats are starting to implicated in primary ebola virus transmission and a couple of other viruses in other countrys.

Not a problem in australia.

Since there isn't any communicable problem, studying the Australian fruitbat viruses might be a interesting avenue of investigation for a simular viruses that are pathenogenic viruses strains.

[devance]

http://www.livescience.com/animalworld/060215_cane_toad.html

evolution of HipHop music?

Toxic toads bound across the northern tropics of Australia faster than ever, thanks to the evolution of longer legs in the few short decades since humans introduced them to their own little paradise.