Base species characteristics?

[Vanigo (OP)]

What do the base species characteristics do? I know xenophobia and diplomacy affect diplomacy, and determination affects the chances your populations will surrender, but what about militancy, expansionism, and trading? And is there anything I'm missing from the first three?

[martinuzz]

I remember reading that militancy is used when determining if ground forces surrender or not.
Expansionism determines an NPR's urge to expand to other systems.
Trading.. Dunno, don't recall.