Slow game because of large number of aliens

[Dilbe]

The game i have been playing has been getting slower and slower, now its around 20 UPS. After reading some causes and analyzing debug information i found out its almost entirely because of aliens. If i use a console command to kill off all aliens and there bases the ups gets back up to 60. Now i read posts of the game creators that that is normal in a game with a large amount of aliens.

Now my question is if anyone knows if the lag is caused only by visible aliens, all aliens in the game and/or aliens in pollution? Or something else...
Knowing this would help me in deciding what aliens to kill to speed up my game. Or i could use smaller radars or something like that.

[Koub]

All aliens in pollution

[Dilbe]

Thanks for the reply. I'll try to kill as much of those as i can (-: