Identifying Bed Bugs
What do bed bugs look like?
The average adult bed bug (scientific name Cimex lectularius) is about ¼ inch (6 mm) long, round, and reddish brown in color. Although they are usually flat enough to slip into a crack the thickness of a credit card, adult bed bugs grow quite a bit in size when they feed and become football-shaped. Juvenile bed bugs range from the size of a pinhead or small sesame seed to the adult size as they pass through five stages of growth (instars). Before feeding, hatchling bed bugs are yellowish tan and can be hard to see. Once they feed and digest their blood meal, bed bugs develop a black spot in the belly, making them easy to identify.
Adult bed bugs can easily slip into a crack the width of a credit card.
Adult bed bugs are about ¼ inch (6 mm) long, round, and reddish brown in color.
An engorged adult bed bug–adult bed bugs grow in size and become football-shaped when they feed.
Before feeding, hatchling bed bugs are yellowish tan and can be hard to see. From left to right: poppy seed, first instar bed bug, sesame seed.
Bedbug nymph after feeding.
Juvenile bed bugs range from the size of a pinhead or small sesame seed to the adult size as they pass through five stages of growth (instars)
Signs of Bed Bugs
Spots on Mattresses and Bed Frame Surfaces
Another sign of bed bugs, and the best way to begin a bed bug inspection, is black fecal spots on mattress and bed frame surfaces. Those small spots are digested and excreted blood from the bug’s gut. Use a wet tissue to wipe it and, if the color on the tissue is rusty, it suggests that you are looking at bed bug poop. Again, it is best to use this evidence as a first step in looking for bed bugs.
As a blood-feeding species, bed bugs puncture the skin in search of blood. They inject saliva to ease the process, which usually results in itchy welts from an allergic reaction to their saliva. People vary in their reaction to bites from no reaction to severe reactions, including blisters or hives. Although bite reactions are commonly mild—itchy red welts—skin reactions cannot be used to diagnose a bed bug issue. Itchy red welts would be a reason to suspect bed bugs and begin looking for them, but welts alone do not mean you have bed bugs.
Bed bug poop on a mattress is evidence of a bed bug problem.
Bed bugs feed on you as you sleep. Bites can look like a rash or welts—or you may have no reaction at all.
Bed bug eggs are bean-shaped, translucent white and very tiny (1 mm), yet visible. Like fecal stains, they don't move and provide excellent evidence of bed bugs.
The closest relatives to bed bugs are the bat bug, Cimex adjunctus, and the tropical bed bug, Cimex hemipterus. Tropical bed bugs are rare in New York, but bat bugs are common and will bite humans when desperate. As their name suggests, bat bugs live with and feed on bats. They also behave differently, and may be observed climbing on walls or in other strange locations. They do not survive long without their bat hosts and do not infest the bed, couches or any places you would typically find bed bugs.
Bed bug or bat bug?
Bat bugs, close relatives of bed bugs, live with and feed on bats but don't infest places you would typically find bed bugs.