Bug:
biter expansion happens very rarely, and when it does happen, the process of creating a new nest is abnormally long.

Game settings:
Death World with default settings, mostly red desert.
Arachnids on normal enemy force (1.2.0): default settings.
No overhaul mods are used.

Mod list:
Base mod (2.0.76)
Space Age (2.0.76)
Quality (2.0.76)
Elevated Rails (2.0.76)
Arachnids on normal enemy force (1.2.0) - default settings
Auto Deconstruct (1.0.12)
Belt Visualizer (2.0.2)
BNL Native Status Light (1.3.7)
calculator UI (2.0.1)
Cleaned Concrete (2.0.0)
Coloured Shortcut Tool Icons (0.0.5)
Disco Science (2.0.1)
Even Distribution (2.0.2)
Factorio Library (0.16.5)
Filter Helper (0.2.24)
Flow Control (3.2.3)
Power Grid Comb (2.0.0)
Rate Calculator (3.3.8)
Soundpack: Alerts and Sirens Updated (1.0.8)
Stats GUI (1.6.1)
Tapeline (3.0.4)