British military scientists are developing robot flies that can be sent in swarms to spy out enemy positions.
The idea sounds like night-marish science fiction, but project leader Dr Rafal Zbikowski believes the first machine insects could be buzzing around his lab within seven to ten years.
He has already produced a non-airborne prototype that mimics the wing beats of a hover fly.
Unlike conventional u nmanned air vehicles (UAVs), Dr Zbikowski's tiny winged drones could operate in confined and cluttered spaces within buildings, stairwells, tunnels or caves.
They would be invaluable for rooting out hidden terror-ists, or - with more peaceful roles in mind - helping to locate victims of natural disasters such as earthquakes.
Industrial applications could involve inspecting chemical pipes or mines.
The US military, which is partly funding the research, has even expressed an interest in using the robots to deliver small explosive charges.
They would be the ultimate "smart" weapon, able to destroy a specifically chosen target - such as a computer - without having to bomb whole facilities.
Dr Zbikowski is based at the Defence College of Manage-ment and Technology at Cranfield University in Shrivenham, Oxfordshire.
His work has a wide range of funding support, including the Ministry of Defence, the US military, and the US space agency Nasa.
Before basing his micro air vehicles (MAVs) on insect flight, he considered fixed wing craft and mini-helicopters.
But nothing compared with agility and efficiency of insects, whose design has evolved over 300 million years.
The lacewing fly, for instance, is capable of making a vertical upside down take-off.
Dr Zbikowski said: "Nothing man-made can approach this - if we can reproduce this kind of performance our mission is accomplished."
The challenge proved more daunting than he expected, however. Much has yet to be learned about the way insects fly, so he found himself pushing the boundaries of biology as well as engineering. So far his team has successfully managed to copy the complex
motion of insect wings, which oscillate and rotate while sweeping forwards and backwards.
A trickier problem is flight control. Somehow insects manage to fly using a paltry 3,000 neurons - yet they solve problems that would trouble a supercomputer.
"Your toaster has more computational power than this," said Dr Zbikowski.