To keep themselves safe in their cockroach homes, jewel wasp larvae spray “disinfectant” inside their hosts.
The jewel wasp Ampulex compressa, like many wasps, is parasitic. Its chosen host is the cockroach, who is first subdued with a sting in the thorax and then given a kind of lobotomy. This surgery, done with a second sting directly into the brain, leaves the cockroach a zombie and robs it of the power to resist. It does nothing as the egg laid inside it hatches and the larva within makes itself at home. By the time it dies, the wasp larva has spun a cocoon in its carcass and is undergoing metamorphosis.
However, a cockroach is not the perfect home. It’s not just the larva living inside it – harmful bacteria such as Serratia marcescens can quickly kill the growing wasp. And so the wasp, in addition to being a brain surgeon, also becomes a hygienist.
To understand how larvae survive, Gudrun Herzner (University of Regensburg, Germany) and her team bored a small hole in each cockroach host and covered them with a transparent slide. She witnessed the larva secreting liquid all around their host, “virtually soaking” the cockroach’s interior with these chemicals. By chance some secretion covered the window and the team analysed it to find out what it was.
Two molecules of this secretion were mellein and micromolide – well known inhibitors of bacterial, viral and fungal growth (and also the first time both chemicals have been found in the same source). We know mellein to be a potent weapon against MRSA and micromolide (taken from plants) has shown promising results against the bacterium responsible for TB.
So could jewel wasps larvae be a new source for antibiotics? It’s possible (though far from certain, as explained in the linked article) but we are in desperate need of new weapons against infections. Herzner agrees, and added, “Evolution might still be working to make an even better combination.”
To see Herzner’s video of the larva in action, click here: http://bit.ly/10eONP9
Photo credit: Ram Gal.
For explanations as to why new discoveries don’t often yield new antibiotics, see this article: http://www.the-scientist.com/