The Pentagon is training an army of bomb-sniffing cyborg locusts.

Tired: a plague of locusts

Wired: a legion of cybernetically-enhanced locusts trained by the US military to sniff bombs

That's the new goal, according to Stars & Stripes magazine:

Navy-funded researchers have discovered that a locust's sensitive "horns" can distinguish between the scents of TNT and other explosives — a development that one day could herald the deployment of bomb-sniffing, electronically augmented bug swarms.
The research by a team from Washington University in St. Louis, published this month in the science journal "Biosensors and Biolectronics: X," is the first proof of concept for a system that aims to tap into the antennae and brainpower of garden-variety bugs to create an advanced bomb-detection sensor.
The work is funded by two Office of Naval Research grants totaling more than $1.1 million, and biomedical engineering professor Barani Raman believes it has the potential to produce a biorobotic sniffer that would be leaps ahead of entirely man-made "electronic noses."

In the Washington University study, which is available to read online, the locusts were able to distinguish between the smells of common explosive chemicals such as TNT, DNT, RDX, PETN and ammonium nitrate — all in less than a second. Which is, admittedly, pretty impressive.

Insects like locusts also offer benefits over, say, bomb-sniffing dogs, in that they already tend to swarm together, and don't require a lot of food and care. There's also less of an ethical concern — no one cares if you attach sensors and cameras to a bug, but even military dogs still inspire a certain protective instinct in their human companions that could discourage such technological enhancements (or the experimentation required to figure out how to use them best).

Over at Forbes, researcher Kelsey Atherton goes more in-depth into the Pentagon's history of insect recruitment efforts:

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.
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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.