Well, the markets are just like nature. At the top

Well, the markets are just like nature. At the top of the food chain are the lions and tigers and bears. Below them are the sheep, gazelles, and rabbits. But underneath everyone are the scavengers like the dung beetles, the roaches, and the maggots. Somebody has to roll up the fecal matter into balls and make a meal out of it, a perfect job for the roaches who by the way resort to cannibalism fairly quickly during food shortages.

I don't think roaches can eat oil though.