Boy's Science Fair Project Led to Major Discovery About Popular Sweetener's Effect on Insects

As the saying goes, you can catch more flies with honey than with vinegar. But a new study, which started as a sixth-grade science fair project, found you can kill more flies with a popular natural sweetener than other sugar products.

Erythritol, a sugar alcohol found in sweeteners like Truvia, was recently identified by a team at Drexel University as a toxin to fruit flies.

While Truvia, a natural sweetener that's a sugar alcohol derived from stevia plant extract, was found toxic to flies, but other similar sweeteners using stevia were not. (Image source: Kimberly Gauthier/Flickr)

When presented with erythritol or a more standard sugar mixture, the scientists found the flies seem to actually prefer the sweetener that was toxic to them. Truvia, which uses a stevia plant extract, is safe for humans with the extract, meeting certain standards, being supported by the Food and Drug Administration in 2008.

"I feel like this is the simplest, most straightforward work I've ever done, but it's potentially the most important thing I've ever worked on," Dr. Sean O'Donnell with Drexel said.

The research all started when Simon Kashchock-Marenda, the son of Drexel professor Dr. Daniel Marenda, decided to study different sugars and sugar substitutes on fly health and development for his science fair project.

"After six days of testing these flies in our house, he came back to me and said, 'Dad, all the flies in the Truvia vials are dead,'" Marenda said. "To which I responded, 'OK...we must have screwed up somehow. Let's repeat the experiment!'"

When they replicated the experiment and it happened again, the father and now ninth-grade student, who is listed as a co-author on the study, sought further help from Marenda's colleagues at Drexel.

In a Drexel University study, flies raised on food laced with erythritol lived for only 5.8 days on average, compared to 38.6 to 50.6 days for flies raised on control and experimental foods without the sweetener.  (Image source: Baudier et al., Drexel University)

"I only use insects to study the brain, so I needed someone who knew something about insects," Marenda said.

Further experiments with O'Donnell revealed that flies raised on Truvia lived about six days, on average, while other flies raised on control or experimental foods that weren't Truvia, like corn syrup, lived between 38 and 50 days.

"Indeed what we found is that the main component of Truvia, the sugar erythritol, appears to have pretty potent insecticidal activity in our flies," Marenda said.

The stevia plant extract that provides the sweetener for Truvia was not the toxic component to the flies though. The sweetener PureVia, which also uses a stevia extract, did not kill the flies. How erythritol leads the fruit flies to die and if it has the same result on other insects are the topics of future research.

O'Donnell said "the chances for widespread crop application are slim" for erythritol products, "but on a small scale, in places where insects will come to a bait, consume it and die, this could be huge."

Drexel and the researchers are filing for a patent on erythritol as an insecticide.

This research was published in the journal PLOS One.

(H/T: Reddit)