Bed bugs do not have eight legs, a common misconception that often leads to confusion with other household pests. However, this article will clarify their biological classification and provide accurate identification tips to distinguish them from similar-looking insects.
Bed Bugs: Insects, Not Arachnids
Bed bugs (scientific name Cimex lectularius) are insects, classified within the order Hemiptera, commonly known as “true bugs.” All insects have three pairs of legs, totaling six. This six-legged characteristic differentiates them from arachnids like spiders, ticks, and mites, which possess eight legs. Bed bugs also have segmented bodies, typically divided into a head, thorax, and abdomen.
Key Physical Characteristics for Identification
Adult bed bugs are typically reddish-brown, wingless, and have a flattened, oval-shaped body, resembling an apple seed. After feeding, their bodies become more elongated, balloon-like, and reddish-brown due to ingested blood. Adults measure about 5 to 7 millimeters in length.
Bed bugs possess antennae and rudimentary wing pads, though these do not allow them to fly. Their flattened bodies enable them to hide in narrow spaces, such as mattress seams or wall cracks. Younger bed bugs, called nymphs, are smaller and can appear translucent or yellowish-white, becoming reddish after a blood meal. Bed bug eggs are tiny, about 1 millimeter long, pearly white, and often laid in clusters.
Common Look-Alikes and How to Tell the Difference
Several small household pests are often mistaken for bed bugs. Bat bugs are closely related and look nearly identical. The main visual difference is that bat bugs have longer fringe hairs on their upper body. A more practical distinction is their preferred host: bat bugs primarily feed on bats and are found where bats roost, only biting humans if their primary hosts are unavailable.
Carpet beetles are another common look-alike. While small and oval-shaped, carpet beetles are often rounder and can have patterned or speckled coloring (black, white, brown, or orange), unlike the uniform reddish-brown of bed bugs. Carpet beetles possess wings and can fly, a capability bed bugs lack. Carpet beetles feed on natural fibers, not blood, and their larvae are also hairy, distinct from bed bug nymphs.
Ticks, which have eight legs, can also be confused with unfed bed bugs due to their flat, oval, and brown appearance. Ticks typically have a harder body and often embed themselves in the skin when feeding, unlike bed bugs that feed and then retreat. Ticks are usually found outdoors in grassy or wooded areas, while bed bugs are indoor pests.