Common Bed Bug
Cimex lectularius
Cimicidae (Bed Bugs), Order Hemiptera (True Bugs)
Physical Description
Small, oval, and dorsoventrally flattened (flightless). When unfed, they are paper-thin; after a blood meal, they become engorged and elongated. They possess vestigial wing pads and distinct antennae with four segments.
Size Estimate
4-5 mm in length for adults; roughly the size of an apple seed. The specimen in the image appears to be an adult or late-stage nymph based on its dark color and visibility against the fabric weave.
Coloration & Markings
Mahogany or rusty-brown color. After feeding, they turn a darker reddish-purple or blackish-brown. They lack distinct patterns like stripes or spots, appearing uniformly colored across the abdomen.
Web Type
Not applicable; bed bugs do not produce silk or webs. They are parasitic insects that hide in crevices.
Eye Arrangement
A pair of compound eyes located on the sides of the head. Unlike spiders, they have complex insect eyes, though their vision is primarily light-sensitive rather than forming high-resolution images.
Leg Characteristics
Six legs (not eight like spiders). The legs are relatively short and adapted for crawling quickly over uneven surfaces like fabric and wood. They lack claws for jumping.
Venom & Safety Information
Venom Information
Non-venomous. They do not inject toxins intended to kill or paralyze; however, their saliva contains anticoagulants and anesthetics to facilitate feeding.
Medical Significance
Not known to transmit diseases. However, bites can cause itchy red welts (dermatitis), secondary skin infections from scratching, and significant psychological distress or insomnia.
Safety Recommendations
If found on a mattress, do not panic but do not move the bedding to other rooms. Use high-heat laundering for linens and consult a professional pest control operator for thermal or chemical treatment.
Habitat & Behavior
Habitat & Range
Found globally. They are synanthropic, preferring human dwellings including homes, hotels, and dormitories. They hide in mattresses, box springs, bed frames, and behind baseboards.
Behavior & Temperament
Nocturnal and reclusive. They hide during the day and emerge at night to feed. They are attracted to the carbon dioxide, heat, and moisture emitted by resting hosts.
Diet & Prey
Obligate hematophagous (blood-feeders). They feed almost exclusively on human blood but will bite other warm-blooded animals if a human host is unavailable.
Seasonal Activity
Year-round activity in climate-controlled indoor environments. They do not have a specific 'season' in domestic settings.
Description
While the user requested a spider identification, the specimen pictured is a bed bug. These wingless, flat insects are specialized parasites of humans. They are master hiders, using their thin bodies to tuck into the smallest folds of mattresses and linens.
Key Features
Flat oval body, six legs, mahogany color, roughly 5mm size, found on a mattress.
Similar Species
Often confused with Bat Bugs (Cimex adjuntus) which require a microscope to distinguish via hair length, or small beetles and spider beetles. Unlike spiders, bed bugs have only six legs and lack two body segments.
Life Cycle
Hemimetabolous (incomplete metamorphosis). Stages include egg, five nymphal instars, and adult. Each nymphal stage requires a blood meal to molt. Females can lay 200-500 eggs in a lifetime.
Ecological Importance
In human environments, they are considered structural pests with no beneficial ecological role. They serve as a food source for some indoor predators like masked hunters (Reduvius personatus).
Conservation Status
Not evaluated; populations are widespread and often considered pests.
Interesting Facts
Bed bugs practice 'traumatic insemination' for mating. They can survive for several months without a blood meal in cool temperatures.
Photography Tips
Get a macro shot of the head and thorax. Lighting from the side helps highlight the flatness of the body. Including a coin for scale is very helpful for identification.
User Notes
Found in matriss
Identified: 2026-07-07T01:46:59.542639