A team of German researchers has discovered that emerald cockroach wasp larva create a disinfecting clear liquid solution in their mouths that they spit out and use to disinfect their food before eating.
Scientists have known for some time that the emerald cockroach wasp has special abilities that allow it to survive – it stings a cockroach twice, once to stun it, and then again to make it docile and then lays an egg on its leg that eventually hatches and bores its way into the hosts body. The larva then lives out its life inside the cockroach, using it as both cradle and food source.
Now it appears, the wasp larva has a special ability of its own. The researchers cut out a small section of the side of a parasitized cockroach and installed a small window. This allowed them to watch the larva inside as it went about its business. They were surprised to find that the larva spewed a liquid out of its mouth and then used it to cover the insides of its host before eating.
Their curiosity piqued, the researchers examined the liquid more closely. They found that it contained micromolide and mellein – substances that are known to work as antibacterial agents. Cockroaches are obviously very dirty little bugs and they harbor all manner of viruses, bacteria and fungi.
One bacterium commonly found on many species is Serratia marcescens – it’s particularly lethal to wasps; for a larva to live inside a cockroach would require some degree of sanitizing. To address the problem, nature has provided the larva with the means of creating its own disinfectant, which also serves as a preservative – no bacteria, no rotting.
The team also tested the effectiveness of the antibiotic fluid, dousing bacterial cultures with samples and found it killed off a wide variety of bacteria. They also collected cockroaches in the wild, comparing those that had been parasitized with a larva and those that had not.
Those with larva in them showed evidence of the bacterial compound created by the larva, while those that were not parasitized, did not, proving that larva were in fact the source of the antibacterial agents.