A compost heap to keep the brood warm

Winter in the game is mostly a temperature problem. The ground freezes from the top down and brood stops growing in a cold chamber, so the only real answer was to dig the nursery deep. I wanted another option that you build yourself.

Leaves fall on the surface now, a few in summer and most of them in autumn. You mark a spot as a heap and some of the workers (5 percent of them at most) start carrying leaves to it. Loose leaves do nothing. A pile of them that gets wet starts to rot into compost, and compost that has air against it gives off heat for about a quarter of an hour.

A hundred cells of it in a closed chamber sits at about 45 degrees and keeps a chamber 4 cells away 10 to 20 degrees warmer than the dirt around it, which is enough to keep brood growing through a frost. The ants also pour the water they bail out of flooded tunnels onto the heap if it's dry.

There are two ways to get it wrong that I like. Rot spreads to anything piled against a heap including seed, so you want it nowhere near the granary. And a heap that's too big and sealed in keeps heating itself, a thousand cells gets to about 160 degrees, so it's several small heaps and not one huge one.

When it's used up it turns into humus, which doesn't do anything yet.