Jewel Wasp Or The Emerald Cockroach Wasp

Jewel Wasp or Emerald Cockroach Wasp

Jewel Wasp or Emerald Cockroach Wasp

What a beautiful creature! The metallic blue green body with contrasting orange colour of the 2nd and 3rd thighs! It flies with shimmering wings and when it sits, its antennae dance! It is the Jewel Wasp or the Emerald Cockroach Wasp.

Location: India

Season: Winter, November

Order: Hymenoptera

Suborder: Apocrita 

Superfamily: Apoidea 

Family: Ampulicidae 

Ampulex compressa

More interesting than the external appearance is the behaviour of the wasp. Unlike most wasps which paralyse and eat their prey, the Jewel Wasp paralyses a cockroach and then puts it into a daze in order for its offsprings to grow inside of the cockroach. The wasp uses its neurotoxin rich venom to sting the cockroach twice, both at surgical precision. The twice stung cockroach readily gets the eggs laid in its body, becomes a living meal for the new born larva. How it paralyses the cockroach is a marvel. 

 The female wasp when ready to lay eggs, flies around looking for cockroaches. She sneaks up on an unsuspecting cockroach and subdues it by holding it with her jaws. With one precise sting, she injects venom into the prothoracic ganglion. The venom causes paralysis of the front legs of the cockroach (due to a post synaptic block at the octopaminergic neurons). Once the cockroach is paralysed, the wasp injects her second dose of venom into the cockroaches head, by piercing the cockroach's exoskeleton with her stinger, precisely locating the ganglion in the nervous system and injecting the venom into it. This second sting controls the mind of the cockroach. The head sting induces first 30 min of intense grooming (due to dopamine in the poison), followed by hypokinesia during which the cockroach is unable to generate an 'escape response'. The cockroach now becomes a puppet in the hands of the wasp. The cockroach also looses less water, consumes less oxygen and survives longer. The wasp leads the cockroach to her burrow, by dragging the whole live but paralysed and mind controlled cockroach which is much larger than the wasp herself. The wasp lays a single egg onto the abdomen of the cockroach. She then blocks the burrow to contain the cockroach inside. The mesmerised cockroach does not resist any of this.

The egg hatches into a larva, which chews its way into the cockroach's abdominal cavity and becomes an endoparasitoid. The wasp's larval development, from egg laying to pupation, lasts about 8 days during which the cockroach must remain alive but immobile. The larva thrives by feeding on the cockroach from inside. The larva produces an antibiotic substance to keep the cockroach's insides clean and free from microbial organisms that reside within. The adult hatches out of the by then dead cockroach. 

This chance spotting of the beautiful wasp has taught me a lot!

References:
http://onlinelibrary.wiley.com/doi/10.1002/arch.20092/abstract
http://onlinelibrary.wiley.com/doi/10.1002/neu.20254/abstract
http://www.bgu.ac.il/life/Faculty/Libersat/pdf/JCP.2003.pdf
http://phenomena.nationalgeographic.com/2013/01/07/if-youre-going-to-live-inside-a-zombie-keep-it-clean/