In India, we have many unusual pests, and one is the so-called emerald cockroach wasp (Ampulex compressa). It looks beautiful even to those scared of insects, because it is metallic-iridescent in blue, green and purple colours. But what makes it interesting for me is its ways of breeding.
Why? Because pest controllers and this particular wasp share a common “enemy”: American Cockroaches (Periplaneta americana).
This wasp has a very efficient approach to cockroach control to us, using them as a food source. Many other animals do as well, but the way of the emerald cockroach wasp is almost unique.
First of all the wasp is much smaller than the cockroach: A female wasp is about 2 cm large, its prey the American cockroach is about 4cm. Looks like an uneven match? Wait and see.
The female hunts for cockroaches; once it finds one, it paralyzes the cockroach with a first sting. The second sting is much more precise and targeted at the area that controls the escape reflex in the cockroach’s brain. The cockroach is still able to walk, but simply sits and waits for whatever comes next. The wasp then bites off the cockroach’s antenna and uses the antenna like a leash to walk the much larger cockroach to a beforehand prepared burrow. The wasp then lays an egg on the cockroach and closes the burrow with small stones.
After the wasp’s larva hatches, it starts eating the paralyzed cockroach, at first outside the body and then from the inside, in a systematic manner in order not to kill the cockroach. That way, it keeps its food source alive and fresh. After the cockroach is totally consumed, the larva pupates. A new wasp hatches and the game begins all over again. Considering all the nasty surprises cockroaches have given me, its good to know that some wasps are giving them such a hard time.
Emerald cockroach wasps are never as common as their prey and I mostly encountered them in the country side, probably due to lesser disturbance by humans. Sounds like a deal to me, emerald cockroach wasps clean the country-side of cockroaches and we take care of the cities.
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Very interesting fact! I’ll probably look for more pics of this wasp so I can get a better view of it.
I recently came across your blog and have been reading along. I thought I would leave my first comment. I don’t know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.
I think I would prefer to breed this wasp to control cockroaches in the natural and chemical-free way.
Hi Cara,
this wasp is actually used for cockroach control purposes in green houses and zoos, where the displayed animals would be harmed if chemicals were to be applied. On top of that visitors of these places really appreicate seeing these wasps, something like pest control with a value ad
I forgot to mention, it would most probably not work as a vector control program, but in enclosed areas, such as Greenhouses or zoos, it should be perfectly fine to control the cockroaches.
Breeding stock of this wasp should be globally available from scientific or entomological departments of universities. I know for sure a few sources where to get them in Germany
Regards and thanks for the interest
I like this artical.Actually i read the ‘sandharbh’ hindi educational magezine, in the artical they mention name of insect ‘tateeya’ who fail the cocarch memary.I dont see the insect so i went through the images and find out the image of the insect.
I want to know how its peralyize the cockroach.which chemical produce by the insect ampulex, who is responsible to paralize the cockrach.this chemical will also harm effect to the ampulex, if the answer is yes so please clearify how it protect himself. if the answer is no why it is not harmful effect.
thanking you…
A team of scientists from California and Israel have looked at the venom from Ampulex wasps and published their results:
http://onlinelibrary.wiley.com/doi/10.1002/neu.20254/abstract
The simplified version (as I understand it from the abstract) is that the toxins in the venom contain a lot of gamma-aminobutyric acid (GABA) that blocks transmission of impulses through one giant synapse in the brain that controls motor function. The wasp injects GABA directly into that synapse to stop it working.
GABA wont do anything in the abdomen of the wasp because it’s a nerve blocking agent- it only works on the nervous system.
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