From beehive pest to plastic fantastic

If you are a fan of honey, then you won’t like Galleria mellonella, otherwise known as the greater wax moth. They are a massive pest. The adults lay their eggs in beehives where the growing caterpillars live off the wax comb and some of the honey.

But these bothersome caterpillars are proving very useful for science. We can buy them in their hundreds from suppliers who breed all sorts of insects for places like pet shops.

They come in little plastic tubs. My lab is just one of many around the world that is using them to study how nasty bacteria cause disease and to find new medicines.

As an example, because caterpillars have a primitive immune system that shares some similarities with our own, we can use them to look at how bacteria interact with different types of immune cells.

Now it seems these caterpillars might be able to help in our fight against plastic. Polyethylene is one of the world’s most common plastics. It’s used to make all sorts of things, including shampoo bottles and plastic bags.

A while ago, one eagle-eyed scientist noticed that the caterpillars appeared to be able to munch their way through the plastic tubs we get them in. It turns out they’re ‘‘plastivores’’.

Now a paper has just been published showing what happens to the plastic when it gets to the caterpillar’s gut.

In their study, Associate Professor Bryan Cassone and his colleagues at Brandon University in Canada fed plastic bags to caterpillars.

Within a day, the caterpillars begin to poop out glycol, a breakdown product of polyethylene. If they fed the caterpillars antibiotics, the amount of glycol went down.

They then looked at what kind of bacteria live in the guts of these caterpillars to see if any were responsible for breaking down the plastic into glycol.

That led them to discover a bacterium from the Acinetobacter family that is able to use polyethylene as a source of nutrients.

There’s obviously much more work to do, but I’m pretty excited by the idea that a beehive pest might be able to help us solve the plastic problem.

Within a day the caterpillars begin to poop out glycol, a breakdown product of polyethylene.