[TruthNtegrity]

Many years ago, I worked for a research lab and there was a guy there who was working on "pheromones" and trying to use Cockroaches to detect the enemy - for use at that time in VietNam, to help warn our guys on the ground where there were underground tunnels, and whether there was anyone in them. I have no idea what happened to the research and whether it ever became useable. I left to work on NASA hardware at Grumman.

But this article reminded me that using the sense of smell has had military applications (or hoped for ones) for a long time.

[Eagle Eye]

Considering that today's technology can 'sniff' and detect at the ppb range, this is highly plausible.