Moths light up the sky in laser show

Dominic Acquista, Departments Editor dominic.acquista@photonics.com

What is the difference between tracking World War II-era German fighter planes and moths in the present day? Based on the laser-based measurement technology at use, it turns out, a great deal. Besides an arguably similar shape and the fact that they both fly, it takes a Grand Canyon-size leap for there to be any other logical connection. But, there is at least one other similarity between the two soaring aviators.

Moths flying into the light. Courtesy of iStock.com/Pobytov

While sirens don’t sound when moths make their flyovers, they do have the propensity to wreak havoc on crop yields during migration. Because of this, modern farmers have taken advantage of World War II-era radar detection systems to track and detect when moths are about to descend into the potential harvest. And this early warning mechanism is being put to use stateside to protect agricultural yields.

In an effort to modernize the technology that was used 80 years ago, North Carolina State University professor Dominic Reisig, an extension specialist in the department of Entomology and Plant Pathology, has collaborated with researchers from the university’s department of Marine, Earth, and Atmospheric Sciences. They are using ceilometers to detect North Carolina’s pesky insect problem during the moths’ normal migratory periods.

The radar-esque devices are already used by airlines to measure the disruptions of commercial flights, such as cloud height, by sending ground-level lasers into the sky. Detectors read the distance that the beams travel as they reflect off of the objects they hit. Objects could include the base of a cloud mass, rain droplets, dust in the wind, or airplanes, but the researchers aimed to discover whether it could detect something as erratic and small as a moth.

To test this, Reisig and his associates decided to take a caged moth swarm and attach them to the base of a drone. Then, the drone would travel to an appropriate testing height, release the tiny beasts, and the ceilometer, the researchers hoped, would be able to track the moths as soon as they crossed paths with the lasers.

Unfortunately, the moths proved to be evasive (or shy) and decided to not participate in the experiment once they were released — meaning they did not pass through the ceilometer’s beam. The experiment was performed again, but instead of using moths, the researchers used confetti as a substitute, this time gaining a positive result from something small and quick-moving enough to simulate a moth.

While they confirmed that the technology can detect moths in flight, further testing is needed to discern whether the signal’s character can be used to differentiate between insects and airborne particles. Whether they emit a unique signal or not, the researchers hope that the system will be able to detect many other types of squadrons, including bug swarms, bird flocks, and even weather patterns. This could create an early warning system for farmers, such as an integrated pest management system, to inform them of dangers to their precious crops, allowing them to truly keep calm and carry on.