SCIENCE LAB SPECIAL : ZOMBIE COCKROACH

 

The Wasp That Came To Dinner. The Horror that eats at the heart of the zombie cockroach.

If you loathe cockroaches, you're going to love the emerald jewel wasp. 

Females of the species Ampulex compressa, known as emerald cockroach wasps are less than an inch long [ 2.5 centimeters ], and decked out in gorgeous, metallic green-blues. 

To complete its life cycle, the wasp stings an American cockroach and injects the much larger insect with mind-control toxins that turn it into a defenseless zombie.

Next, the wasp drags the subdued cockroach to shelter, lays a single egg on its leg and seals host and egg under dirt and debris.

After six days, the egg hatches; the larva carves its way into the cockroach's chest and begins to devour the helpless insect from the inside out.

It is one of the more macabre horror stories in nature, a continuing tale fit for

Halloween.There are about half a million species of parasitic wasps, and many reproduce in a similar fashion.

Many of them zero in on insects that humans don't really mind seeing brutalized : roaches, crop pests and invasive species.

But there's something scientists had not noticed about jewel wasp's routine until recently.

'' Since the 1800s, people have sort of had this mantra that parasitoids selectively avoid eating the vital organs of their host so that they can keep it alive,'' said Kenneth Catania, a neuroecologist at Vanderbilt University in Nashville.

''And what I have found is that this parasitoid goes straight to the heart of the cockroach and eats it.''

That, Dr. Catania suggested, may speed up the process, requiring the larva to eat faster than the larvae of other parasitoids that do, in fact, avoid the vital organs. [ Jason Bittel ].