The US agency DARPA has been researching techniques for “augmenting” insects for nearly 2 years
see here for the official tender - specifying the desired capabilities
“the delivery of an insect within five meters of a specific target located at hundred meters away, using electronic remote control, and/or global positioning system”.
Once at the target, DARPA says, “the insect must remain stationary either indefinitely or until otherwise instructed … [and] must also be able to transmit data from [Department of Defense] relevant sensors … include[ing] gas sensors, microphones, video, etc.”
Gizmodo has pictures of a cyborg moth here
The implantation technique involves inserting the relevant microchips into the pupa of the insect - which has the capability to grow ‘around’ foreign objects
This machine/insect combination avoids many of the problems involved with micro UAV (Unmanned Air Vehicle) design. It simply uses an existing (and highly efficient) framework to transport a sensor payload.
There has been speculation about weaponizing the design - perhaps with ‘tailored’ viruses.