Studying insects in flight can be difficult. They're usually tethered in place, although this may affect the manner in which they fly. That's why scientists from the University of California, Berkeley and Singapore’s Nanyang Technological University (NTU) took a different approach – they installed an electronic backpack on giant flower beetles, allowing them to be remotely controlled while in free flight. The technology not only gave the researchers a better insight into how the insects fly, but it could also find use in areas such as search-and-rescue.
The backpack consists of a commercially-available microcontroller, a wireless transmitter/receiver, and a 3.9-volt micro lithium battery. It also includes six electrodes, which were wired to the beetles' optic lobes and flight muscles.
The beetles were first placed in a closed room equipped with eight 3D motion-capture cameras. Using radio signals transmitted to the backpack once every millisecond, the researchers then selectively stimulated different muscles. By doing so, they were able to get the insects to take off, turn left or right, or hover in place.
At the same time, the backpack also transmitted neuromuscular data to a computer.
Among other things, it was discovered that the beetles' coleopteran third axillary sclerite muscle played a key role in their ability to turn. In the past, it had been assumed that the muscle was used only for folding the wings underneath the wing covers.
According to the study's lead author, NTU's Prof. Hirotaka Sato, the backpacking beetles could have applications beyond entomological research. "We could easily add a small microphone and thermal sensors for applications in search-and-rescue missions," he said. "With this technology, we could safely explore areas not accessible before, such as the small nooks and crevices in a collapsed building."
A paper on the research was recently published in the journal Current Biology. Video of some of the flights can be seen below.
Similar research is being conducted at North Carolina State University, where researchers are remotely steering backpack-equipped cockroaches.