Cimex lectarius has a known origin of 2 million years ago in Saudi Arabia. They are thought to have developed from the bat bug, Cimex pilosellus. Both species rarely interbreed, coexist on the same host, or change their primary host from bats to men or vice versa. During the caveman era, it is thought that bat bugs descended onto neanderthals living in caves. Over time, they adapted themselves to feed primarily on humans. To find out more about the bed bug genome click here to view Dr. Booth’s website.