@dr2chase @cstross @isaackuo You can do image recognition with insect hardware.
It's why I don't expect we're going to see a "recognise faces" approach. Think "biting insect"; it's got several sorts of toxin and enough circuitry to go "is it warm?" and "does it have a heartbeat?" and some way to prefer stinging skin to armour.
Add in a few simple eusocial rules and some return-for-reload capacity if you can, but even as a one-way munition, the cost per corpse is likely much lower this way.