Crystal Express, by Bruce Sterling

Somehow I had never read this before, despire reading all his later work.

It is great! The first story is about future humans sending out emissaries to various newly discovered alien species, and trying to use them for advantate. They encounter one that is like a giant swarm of ants, which can co-opt various invading species, and uses genetics to control the incentives of every caste. It's great, sterling's writing is really great. It's really detailed, and I trust him to thought about the important things.