Turns out, the sudden disappearance of Earth's 5,000 to 10,000 cockroach species would have ramifications far beyond your filthy apartment. [Chocolate Allergies Linked to Cockroach Parts] Worldwide, the insects are a significant food source for many birds and small insectivorous mammals, such as mice and rats. (Even humans eat them in some parts of the world.) None of these animals rely solely on