MICHEL MARTIN, HOST:
If you ever wondered what it sounds like when an aphid eats, here you go.
(SOUNDBITE OF APHID EATING)
MARTIN: And here's the sound of a corn rootworm chowing down.
(SOUNDBITE OF CORN ROOTWORM EATING)
MARTIN: OK, so maybe insect dining habits are not your jam. But a University of Wisconsin-Madison entomologist has obsessed over insect sounds for years, and she's developed tech that she calls the Insect Eavesdropper. Lina Tran with WUWM reports on a tool meant to help farmers defeat costly pests.
LINA TRAN, BYLINE: A few years ago, this huge sugarcane farm in Indonesia - almost a hundred square miles - came to Emily Bick with the challenge - come up with a way to directly and immediately detect the moths chewing up their sugarcane. Maybe most importantly, without any harm to the crops themselves.
EMILY BICK: We lose 20% of our crop to these pests, so we should probably be doing something if we want to conserve more land for, you know, nonagricultural use.
TRAN: As she ponders her task, Bick remembers that back in the '80s, scientists used gramophone needles - which are sensitive to vibrations - to listen to insects that tap on plants to communicate. And in the '90s, scientists aimed devices called laser vibrometers at plants. Another decade after that, people strapped accelerometers to plants - the little devices in our phones that detect motion. These were all different, expensive ways of tracking the vibrations that come from insect-plant interactions. Somewhere between vibrometers and accelerometers, Bick falls deep in a research hole.
BICK: I kind of got myself caught in an area where I'm sure I would have been on some government watch list if I had to search this too much. But I basically realized that the way that spy agencies listen to people is by attaching these things to walls, and the walls would vibrate. And then that vibration would be translated into, you know, what did this person say?
TRAN: And so she's thinking, how do I become a spy on a budget? She lands on contact microphones. Musicians use them a lot. They have a little brass disc that sits on a solid object, and every time there's a vibration, the mics register an electrical signal.
BICK: Now, when corn rootworms feed on the roots, the signal or essentially the vibrations translate from the root system to the stem, and that's where we're picking it up. So we're using the plant as the musical instrument, as essentially the outside of a guitar.
TRAN: So she tests it out with a colleague.
BICK: We clipped it to desks, and we started talking and we started tapping. And the fact that the desk couldn't hear our voice vibrations, but it could distinctly and clearly hear those taps enabled us to say, OK, let's take this technology and move it forward.
TRAN: To create the Insect Eavesdropper, it captures the vibrations insects make when they feed on plants and runs them through an algorithm to identify the bug. I visited Bick and her team in a cornfield on a muggy day. They were micing the corn for an experiment with corn rootworm.
BICK: And we can walk through...
TRAN: Yeah, yeah.
BICK: ...Over here.
TRAN: All this corn is sweating under the sun, exactly the conditions that Bick is looking for.
BICK: Walk this way.
TRAN: Because the corn is photosynthesizing and chock-full of sugar, which insects love. Their findings aren't published yet, but as of now, their algorithm is 80- to 96% accurate, depending on the species. They're aiming to get the Insect Eavesdropper on the shelf in a couple of years.
For NPR News, I'm Lina Tran in Milwaukee.
(SOUNDBITE OF SONG, "GOOD VIBRATIONS")
THE BEACH BOYS: (Singing) I'm picking up good vibrations.
MARTIN: This story was originally reported for NPR's science podcast Short Wave, where you can learn about new discoveries, everyday mysteries and the science behind the headlines. Transcript provided by NPR, Copyright NPR.
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