Emerald Cockroach Wasp (Jewel Wasp)

Ampulex compressa — the emerald cockroach wasp, also called the jewel wasp — is one of the most extraordinary parasitoid wasps in the world and a flagship species in modern neuroethology research. The species is endemic to tropical regions of Africa and South Asia and has been introduced to Hawaii. Adult females are 22 mm long with brilliant metallic emerald-green bodies and bright orange thighs. The species' hunt is precisely choreographed and is one of the most-studied parasitoid behaviors in entomology. Step 1: a hunting female finds an American cockroach (Periplaneta americana, far larger than the wasp) and approaches from above. Step 2: the wasp delivers a quick first sting to the cockroach's prothoracic ganglion — temporarily paralyzing the cockroach's front legs. Step 3: with the cockroach immobilized, the wasp delivers a SECOND, much more precise sting directly through the back of the cockroach's head and into the central complex of the brain — specifically into the cells that integrate sensory input with motor output to initiate voluntary movement. The neurotoxic venom (containing neuropeptides including ampulexin and a cocktail of GABA-antagonists) leaves the cockroach with normal sensory perception and normal muscular function — but unable to initiate movement on her own. The cockroach enters a 'zombie' state. Step 4: the wasp grabs the cockroach by one antenna (the antenna is now functional only as a 'leash') and leads her — walking on her own legs — into the wasp's underground burrow. Step 5: the wasp lays a single egg on the cockroach's leg and seals the burrow with pebbles. Step 6: the wasp larva hatches in 3 days, feeds first on the cockroach's hemolymph, then chews into the abdomen and consumes the still-living, still-zombified internal organs over 8 days, saving the vital organs for last so the cockroach remains fresh until the larva pupates. The species is the textbook example of insect host manipulation and has been the subject of decades of neurobiological research — Ram Gal and Frederic Libersat's work on the precise neuroanatomy of the second sting is a flagship case study.