Locust Bomb Sniffers Just The Latest Military Insect Cyborg

With a chittering of wings and a flickering of antennae, the locusts buzzed into position. Released from their cage, the swarm buzzed across the road, senses tuned and trained to the scent of TNT. First one lands, and then another, and near the corner of the street, hidden under loose cardboard and a fake, papier-maché rock, is the improvised explosive device. The swarm monitor plots the location on a tablet like a game of minesweeper, and waits for the swarm to identify more hidden hazards.

This is not, yet, the reality of war, but a possible future based on present research undertaken by the Office of Naval Research. Using electrodes, transmitters, and a little bit of glue and insect surgery, research successfully demonstrated the ability of cyborg locusts to detect explosive compounds. The project began in 2016, and this month researchers at Washington University in St. Louis published their results in the journal Biosensors and Biolectronics: X.

“The new, peer-reviewed study found that the tiny herbivores can distinguish not only between the vapors from explosive chemicals like TNT, DNT, RDX, PETN and ammonium nitrate, they can do so within a fraction of a second and can sense where the scent is coming from” reported Stars and Stripes.

Why locusts?

Humans have already trained dogs, with their highly attuned sense of smell, to detect explosive compounds, but dogs have limitations. They are expensive to train, they can sometimes produce incorrect assessments by trying to please human handlers, and humans form an emotional attachment to dogs, limiting the kind of scenarios where it is safe or plausible to send dogs to look for bombs.

Locusts, unlike dogs, are disposable. And, unlike small robots, locust cyborgs are cheap.

Able to subsist on small amounts of local vegetation, every locust is a potential self-powered, self-steering host for a useful sensor package. Outfitting locusts with sensor backpacks is the culmination and continuation of a long line of cyborg insect research, largely but not exclusively undertaken by DARPA.

In published research slides going back to at least 2006, DARPA researchers examined the challenge of making efficient, useful robots at a small, insect-like scale. These “Micro Air Vehicles” offer a whole host of value, from being difficult to observe to flying into small and otherwise-inaccessible spaces. 

Making a machine fly at the size of an insect runs into hard constraints on power and engineering capability. The Black Hornet, a sparrow-sized drone, is at about the technical limit of what can be built, while still retaining a battery, useful camera, and a control system. Initially offered for around $100,000, its price has fallen in recent years to around $20,000. 

What if, instead of trying to engineer robots down to the size of insects, the DARPA teams figured, they could instead turn insects into useful robots? This research included a lot of inserting electrical backpacks onto cockroaches, as well as this truly horrifying attempt to insert electrical microcontrollers into moth pupae and have the moth finish metamorphosis.

Besides an unsettling appearance, insect cyborgs offer a great deal as potential frames for sensors. The bodies are already adapted to the size and energy needs of micro-robotics. Adding a battery that can power the sensor and a little electronic backpack works, if the size can be kept small enough.

Part of the innovation in the Washington university study is installing the electrodes on locust brains in such a way that it leaves the locust mouth unobscured, allowing it to remain in the field and forage for a few days after it was deployed.

The locusts also work better in a swarm, with the researchers finding an accuracy of 80 percent in chemical compound detection when using data from seven locusts, compared to an accuracy of 60 percent when just using one locust.

These results so far come from the lab, but if there is continued interest in using locusts as cheap, expendable sensors, expect to see field testing and, ultimately, combat deployment.

Then, and only then, will we know if cyborg electronics were worth the buzz.

Watch a video about the locusts below: