Bed bug

Usually in mattresses, bed frames, upholstery, cracks, and other sheltered indoor areas near sleeping hosts.

Feeds primarily on blood, usually human blood, using piercing-sucking mouthparts. It may also feed on other warm-blooded animals.

Nocturnal and hiding during daylight; adults, nymphs, and eggs occupy tight crevices. Females lay eggs repeatedly, and infestations spread through luggage, furniture, clothing, and wall voids.

Bites commonly cause itchy, irritated welts, though some people show no reaction; bed bugs are not established disease vectors. They provide little meaningful ecological benefit indoors.