Slitherine

My personal favourite: "The park ranger approach"

So who is doing it and how?

I just love playing the park ranger and enjoying my army of indigenious live forms, all conquered by my pheromone-love-spreading ranger dudes.

Orbital Bombarments and a nice "Pheromone-Love" Plane helped me getting hold of an Aspidoch pretty easy.
Early in game some cannon fodder and timing brought me a Devourer (That flying monster that can chew through cities pretty easily), which - positioned at the right chokepoint - helped contained the rebellious uprising of these untamed locals...

Additionally I find the spitting artillery unit one of the best support units, much better than the mechanical artillery units. With some flanking and a flamethrower the are "convinced" pretty easily even with a low budget army.

I do this by rushing Preigniters/Steel Armor -> Ships/Planes (Whatever is shortest path to).

At first I capture Drones/Spitters en masse. I then suicide the Drones into Galeths/Devourers to weaken them for the capture. I do this aggressively. I usually have 1-2 Galeths/Devourers by turn 70ish.

With boats/planes, I hunt for an Aspidoch, not to capture, but to kill for the advancement. Leviathans however I do capture. Much faster, better water control.

At this point I can either win right away or I can turtle up to play with the AI cause games like these are really short.

So the concept to keep in mind is that a good wild life reserve keeps animal populations under control. In the game's case this involves provoking hive stacks and roaming Galeths/Devourers into attacking well fortified cities. Infantry upkeep is cheap as hell so I usually keep a stack of like 10 Park Rangers (Trooper/Hellfire/Steel Armor/Xenomorph pheropod) in my frontier city or Capital if I haven't expanded and use captured Drones to Provoke passing aliens and Spitters to weaken them. Beyond that I just transition into a normal game.