Bed bug

Primarily human dwellings, hiding in mattress seams, bed frames, upholstery, cracks, and other dark crevices.

Feeds exclusively on blood, usually human blood, using piercing-sucking mouthparts. It is mainly nocturnal.

Wingless, flattened adults hide during daylight and emerge at night. Females lay small eggs in sheltered cracks; infestations spread through luggage, clothing, furniture, and adjoining rooms.

Bites cause itchy, localized welts and can trigger allergic reactions, though bed bugs are not proven major disease vectors. They provide little ecological benefit in homes and are difficult to eradicate.