You should look for traces of the insects in the folds of your mattresses, box springs and other places where they are likely to hide. You might be able to find their papery skins, which get cast off after molting and look like popcorn kernels but are smaller and thinner, Harlan said. They also leave small, dark-colored spots from the blood-filled droppings they deposit on mattresses and furniture. If you can touch the spot with a water-soaked towel and it runs a rusty, reddish color, you're probably looking at a fresh drop of bedbug feces, Harlan said.
Bed bugs typically feed at night when we are sleeping. Even though these pests commonly feed for 5 minutes, the bite itself is painless and usually goes undetected at the time. In fact, bed bugs inject an anticoagulant (a blood thinner) as they feed, which makes feeding easier for the bed bug and also less detectable to you. Although you may not see the bed bugs, or feel their bites, they know when you are around. Bed bugs are attracted to warmth and carbon dioxide. So, if you are alive, warm, and breathing - then you are broadcasting loudly and clearly to all nearby bed bugs that "dinner is served!"
The size of bed bug bites varies with a number of different factors. Bed bugs inject an anti-coagulant along with their saliva when they pierce the skin to take a blood meal. This anti-coagulant is mostly responsible for how a person reacts to the bite and determines the size of the bug’s bite. Since people will have various sensitivities to the bed bug’s bite, the size of the bite will vary, as well. Another factor that influences the size of a bed bug reaction is the number of times a person is bitten. Bite reactions of people bitten many times are also variable, and their response may be either more or less intense as the number of bites increases.