An age cost, especially if it ramps, with a delayed start time can also encourage this. If you don't start accessing the age cost until say bots are 100 cycles old, then there is tremendous selection pressure towards short generation times. Its the best way for a population as a whole to avoid costs I.e. give all your nrg away to your offspring before you get old enough for the program to start charging you.
I've toyed with adding a cost for reproduction or a minimum age to reproduce, but such things should be evolved and species specific.