Humans have a long history of sending robots into dangerous places. We have already sent them to Mars, and the potential applications for espionage are mind-boggling. The catch, however, is that robots are still expensive and time-consuming to make, and none has yet improved on nature.

One solution is to piggy-back on existing biological systems, which have been delicately engineered by millennia of evolution, and tweak them by adding mechanical parts. This basically means hijacking a nervous system using electronics, and it makes sense: many living organisms move faster than robots, and their sensory capacities can far outstrip artificial sensors (which is why sniffer dogs are still used at airports). The principle is simple, albeit an ethical minefield; if you know the right areas of the brain to target, you can plug in electrodes and either control movement or mainline sensory information.

Of course, it’s not so simple in practice. Rats and mice can carry small video cameras, but there are places that even a rat can’t go, and it would also be pretty obvious that a rodent with a miniature AV setup strapped to its back was up to no good. The perfect spy would be a small, unobtrusive animal that’s highly mobile and easily replaced. Enter the cyborg bugs, a collection of remote-controlled insects developed by the US Defense Advanced Research Projects Agency (DARPA).

Neurosurgery on insects might sound difficult, but several research teams have done it successfully as far back as 2008. One group, led by David Stern, connected a moth with a system controlling its wings. The researchers inserted flexible plastic probes into moth pupae a week before the adult insect emerged, and the thickness of the probes alone – only a few hundred microns – gives some insight into the precision required for the surgery! Even so, most of the moths survived to pupate, with the probes stably connected to their flight muscles. After attaching wires to the probes, the researchers could control wing movements by delivering electrical signals to the moth’s flight muscles.

Another DARPA-funded team, led by Michel Maharbiz, developed a battery-powered beetle, controlled by electrodes implanted into the ‘flight centres’ of its brain. New Scientist even released a series of video clips online (originally from the conferences where both projects were first presented), which is still available on YouTube under the title ‘Cyborg insects’. It’s simultaneously surreal, oddly cute, and a little disturbing to watch.

Cyborg insects have even started invading the classroom. In 2013, a start-up company called Backyard Brains caused controversy when it released a ‘RoboRoach’ kit for general sale. To make a RoboRoach, you first need to sedate the cockroach on ice, then perform surgery to attach electrodes to its antenna and a ‘Bluetooth Roboroach backpack control unit’ to its carapace. Backyard Brains also supplies an app for remote-controlling the RoboRoach with a mobile phone. The company’s aim was for the kit to help children and non-academics learn about neuroscience; however, science writers and animal rights activists alike raised serious concerns about the use of animal experiments and a crude form of mind-control surgery as a teaching tool. The kits are still available to purchase – an ethically-fraught birthday gift, perhaps?

Of course, hybrid moths or rogue RoboRoaches will not turn up in your house any time soon. All the bulky electronics attached to the current generation of cyborg bugs would make anyone reach for the flyswat, and RoboRoaches adapt to the stimulation from their backpacks within minutes. One day, though, we might be able to conceal all the necessary equipment within the insect itself – and then we should start avoiding every fly on the wall. Especially if it’s a real one.