A small insect or a mosquito over your ear may now be much more than simply annoying. Those could easily be micro drones which now come in a swarm of bug-sized flying spies.

­In an effort to create a hard-to-detect surveillance drone that will operate with little or no direct human supervision in out of the way and adverse environments, researchers are mimicking nature.

The University of Pennsylvania GRASP Lab showed off a network of 20 nano-quad rotors capable of agile flight, which could swarm and navigate in an environment with obstacles.

This is another step away from bulky heavily armed aerial vehicles or humanoid robots to a much smaller level of tiny remote-control devices. While current drones lack manoeuvrability, can’t hover and move fast enough, these new devices will be able to land precisely and fly off again at speed.