How much of an impact does population have on influence. In my current game I represent 60% of the galactic population and have a LOT of influence. After some of the lesser powers declared war on me and started to lose they immediately handed over all their worlds to the 2nd most powerful civ, I guess to spite me.

What happend next is weird. The 2nd most powerful probably doubled in size after the handover, but their population and influence still did not match mine.

Then I quit for awhile. When I restarted my game several hours later the galaxy had dramatically changed. Now my rival's borders, who got all the star systems hand to him, have expanded drasticlly leaving many of my most powerful worlds on the wrong side of the border. How can this be? Stats show I still have a huge lead in influence and population, so why are my borders shrinking? Just a another note, I've destroyed all alien influence starbases, so they can't be getting a benefit from those.

I always thought borders were determined by influence?