I spotted this shiny creature on the trunk of a mango tree, but wasn’t sure what it was. So I searched online using the striking details – iridescent green, red on legs, Hawaii – and the first result was a post on whatsthatbug.com. It was headlined, ‘Emerald Cockroach Wasp from Hawaii turns Roaches into Zombies!!!’ (link here). That got my attention! Within that posting was a link to a longer post with more details (here).

In brief, the female Emerald Cockroach Wasp (Ampulex compressa) stings a cockroach to temporarily disable its front legs. It does this to buy time to deliver a second sting to a precise spot in the cockroach’s brain that controls the roach’s escape reflex. The roach isn’t paralyzed, but it just stays where it is, that is until the wasp takes it by the antenna and leads its zombie prey back to her burrow. There she lays an egg on the roach, before walling up the burrow’s entrance. Back inside, the roach just waits while the egg hatches and the larva eats its way inside the roach and devours the roach’s organs. Four weeks later, a new wasp emerges from the roach and the burrow.

I was astonished to learn about this, in particular how, for the second sting, the wasp locates the exact spot in the roach’s brain using sensors on the stinger.

The source of the whatsthatbug.com description comes from Carl Zimmer who has a great article here. More information about this remarkable wasp can be found here, here, and here. And finally, a must see video of the wasp in action, including leading the cockroach to its lair, can be seen here.