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 â€œenemyâ€:Â 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 cockroachâ€™s brain. The cockroach is still able to walk, but simply sits and waits for whatever comes next. The wasp then bites off the cockroachâ€™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 waspâ€™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.