Adult bed bugs
Adult bed bugs are roughly the size of an apple seed, measuring five to seven millimeters. Their bodies are oval-shaped, flat, and brown in color, but after feeding on a blood meal, they swell in size and turn a reddish hue. This engorgement makes them easier to see and identify. Unlike many other insects, adult bed bugs are wingless and rely on their flattened bodies to squeeze into tight spaces, such as mattress seams, box springs, and headboards. They are often mistaken for similar-looking insects like bat bugs or carpet beetles, but their feeding habits and size set them apart.
Nymphs and eggs
The younger stages of bed bugs—nymphs and eggs—are even smaller and more challenging to spot without careful inspection. Nymphs, or juvenile bed bugs, are translucent when unfed and measure around one millimeter at their smallest stage. As they grow, they molt through five developmental stages, becoming slightly larger and darker after each molt. Bed bug eggs are even tinier, measuring only about one millimeter. They are whitish and oval-shaped, resembling grains of rice.
Female bed bugs lay eggs in hidden areas like cracks, mattress seams, and headboards, ensuring their survival in well-concealed locations.