How fast will biters evolve if I wipe out their bases.

[thebunnyrules]

I'm kind of cramped in my current base and am looking to expand outwards. I need to clear biters nest on the map to safely expand but I'm worried about that by killing them I'm making them stronger. How much of a thing is that? Can I get away with wiping out 20 nests without having them making evolutionary leaps?

[DaveMcW]

20 nests will probably trigger their next upgrade, but you should be fine.

Focus on getting oil and flamethrower turrets, which can defend against the highest levels of biter evolution.

[Koub]

In addition to DaveMcW's answer, it also depends heavily on the size of the nests (in terms of number of spawners) and at what evolution factor you're currently at.
If you were at 0 evolution, killing a single spawner would bring you to 0.002 evolution
At the first evolution leap, a destroyed spawner would still add almost 0.002 evolution
At the second evolution leap, a destroyed spawner would still only add 0.0005 (a quarter of the "full" evolution cost)
At the third and last evolution leap, a destroyed spawner would still only add 0,00002 (a hundredth of the "full" evolution cost)

A spawner destroyed is roughly equivalent to 8 minutes and 20 seconds of time when it comes to evolution.

[thebunnyrules]

20 nests will probably trigger their next upgrade, but you should be fine.

Focus on getting oil and flamethrower turrets, which can defend against the highest levels of biter evolution.

In addition to DaveMcW's answer, it also depends heavily on the size of the nests (in terms of number of spawners) and at what evolution factor you're currently at.
If you were at 0 evolution, killing a single spawner would bring you to 0.002 evolution
At the first evolution leap, a destroyed spawner would still add almost 0.002 evolution
At the second evolution leap, a destroyed spawner would still only add 0.0005 (a quarter of the "full" evolution cost)
At the third and last evolution leap, a destroyed spawner would still only add 0,00002 (a hundredth of the "full" evolution cost)

A spawner destroyed is roughly equivalent to 8 minutes and 20 seconds of time when it comes to evolution.

Thanks for the quick feedback guys!