This month’s creature was something that may have been better suited for October as it goes very well with a Halloween theme. The cockroach jewel wasp is a very colourful and pretty looking wasp but deadly. Not lethal for humans, but they are the creatures of nightmares and spooky fireside stories for the cockroach. Get ready to gasp or say gross as this is not for the squeamish… they turn cockroaches into zombies and lay their eggs inside them. *Queue lighting and flashing lights!*
Let's begin with a brief description. The cockroach jewel wasp is solitary wasp of the Ampulicidae family. Since they use cockroaches for the reproductive process they are technically a parasitoid, which means that they spend a significant portion of their lives attached or within a single host organism. Unlike a true parasite, a parasitoid will sterilize, kill, or sometimes consume the host when it is done with it. Also since this wasp is a parasitoid on another insect it makes it part of the entomophagous parasites.
The wasp is like your typical wasp - it has two wings which it uses to fly, two antennae, a head, a thorax and an abdomen equipped with a stinger. One thing that is instantly noticeable about the Jewel Wasp is that it has a metallic blue-green body with red legs. The female is about 22mm (.87 inches) long. The male is much smaller and does not have a stinger, as usual with the insect kingdom the female is much more awesome then the male.
Now to the more interesting part… When the female wasp is ready to lay its eggs it finds a nice and tasty cockroach (or roach for short) and flies on top of it. With the precision and exactness of a surgeon it stings the roach directly into specific ganglia by its head and injects venom to mildly and reversibly paralyze the roach. (Ganglia are a cluster of nerve cells so it’s like getting a needle into your spine at your neck.) Then after the roach is paralyzed it stings another precise spot in the roaches head ganglia, basically its brain section that controls the escape reflex. Once this is done the roach will groom itself for a while and doesn't try to escape which is very unusual behaviour. Now the wasp has created a cockroach ZOMBIE!!! *queue evil laughter*
The wasp will now chew off half of each of the roaches antennae, this is believed to be done to replenish liquids or to regulate the amount of venom in the roach as too much will kill it and too little will let it recover before the larva has grown. The wasp is not able to carry the roach but will lead the roach to a burrow, dragging it by the remains of the antennae and then laying a 2mm long egg on the roaches abdomen. It will then bury the entrance with pebbles to protect the roach from predators and to keep it in. Makes you wonder if O’Bannon got his inspiration for the movie Alien from stuff like this.
The cockroach jewel wasp is no Dr. Frankenstein nor are they going to start the likes of Walking Dead but it is kind of scary and awesome to know how such a thing could have evolved. It sort of makes you wonder how lucky we are as mammals and as humans to be the dominant species otherwise it could a much scarier place out there.
With the ability to zombify cockroaches, its gross reproduction process and how something so beautiful can be so deadly I nominate the Cockroach Jewel Wasp as my Epic Creature of the Month!