Homemade Bedbug Detector in Action

Q. I am confused about finding bedbugs with the technique you described. Do you put the cooler in its plastic dish directly on top of the mattress? Does it have to be at night? Should the jug be upright or lying on its side?
I was in Africa and have been itching since my return. I do have small welts and don’t know what they are, so I am anxious to find out if my bed is infested.
A. Despite the name bedbug, these insects are not limited to the bed and can travel around the room. That’s why the “detector” developed by Rutgers scientists and described in Science News (Jan. 16, 2010) can be set up in a corner of the bedroom on the floor.
Here’s the technique: bedbugs locate people by sensing carbon dioxide, so to trick them you will offer them a source of carbon dioxide. Two pounds of dry ice in a third-gallon cooler (like a Coleman jug) with a flip-up spout will do that. With the spout slightly open, the gas leaks out slowly.
Place the cooler in a plastic pet-food dish and tape a piece of paper to the outside of the dish as a gangplank for the bedbugs to climb. Dusting the dish with talcum powder makes it hard for them to get out. Within 12 hours there should be bedbugs in the bowl if you have them in the room.