(Hopefully this is a very simple question, but I am a very new player and I don't find a straight answer in the game manual).

In my current game of Master of Orion 1 the Silicoids control these two planets (see attached screenshots), with a population way over the maximum limit. Is this a trait of the Silicoids, or might there be another explanation? I know from reading the manual that the Silicoids can settle any planet within range without researching controlled environment technologies (which doesn't seem to apply here) and that they are immune to waste (which I guess is the answer). If so, how do waste work and how do Silicoid planets react to it? Is the maximum pop number displayed in the interface different than the one applied to the Silicoids?

One silly thing about the Silicoids is that the waste that they usually can ignore prevents them from (or hampers them) using Clone. It's not very logical and looks like a bug or oversight at first, but it may have been implemented for balancing reasons.

Thank you very much for your answers. :) All is clear now.

Silicoids differ from the other races in several ways and I could go on about these peculiarities. They start strong but will inevitably be outpaced by others unless they are leading and winning. No athmospheric terraforming nor soil enrichment for them.