Captive biter spawner

A captive biter spawner is a building used solely to produce biter eggs, and it is the only source of biter eggs in the game. It does not require a recipe or any input items beyond a continuous supply of bioflux. Once supplied, it produces 5 biter eggs every 10 seconds. The output slot can hold up to 100 biter eggs; if it is full, the production cycle continues but no additional eggs are added. Eggs stored in the output slot do not begin to spoil until they are removed, and eggs that have been removed cannot be inserted back into the spawner.

Captive biter spawners are obtained in two ways. At first, the only way to create one is to fire a capture bot rocket at a biter spawner on Nauvis, which slowly converts the target into a captive spawner over 20 seconds. The capture process can be interrupted if the capture bot is attacked and destroyed by nearby biters, and the spawner continues producing biters while it is being captured. After reaching Aquilo and researching captive biter spawner, the player can craft them directly and place them by hand. A captive spawner kept in the player’s inventory or another container spoils after 30 minutes, at which point it turns into a behemoth biter.

A captive spawner requires a constant supply of bioflux to stay healthy and productive. If it starves, it stops producing biter eggs and loses 1 health per second, regardless of quality. When its health reaches zero, it transforms back into a normal biter spawner with full health and must be captured again. While consuming bioflux, it restores health at 1 per second. Since bioflux has an energy value of 6 MJ and the spawner consumes food at 100 kW, one item of bioflux lasts exactly one minute, regardless of freshness. Because a normal-quality bioflux item spoils after two hours, a single captive spawner can consume 120 items of the same age before any of them spoil.

Previously captured spawners that have starved and reverted do not become valid targets for automated weapon systems, including turrets and artillery, except for rocket turrets and spidertrons loaded with capture bot rockets. They still consume pollution and continue to spawn biters, and those biters are affected by the evolution factor.

Quality does not improve biter egg output: a higher-quality captive biter spawner does not yield higher-quality biter eggs. However, if a captive spawner reverts to a normal biter spawner for any reason, it keeps its quality. The resulting spawner will then spawn biters of that same quality, and those biters can form expansion groups that also retain quality when they successfully expand. This can spread higher-quality biter spawners, spitter spawners, and even worms across the planet if the reverted spawners are not contained.