What do domestic bedbugs feed on in an apartment?

The Primary Food Source: Human Blood

Why Human Blood is Preferred

Domestic bedbugs subsist almost exclusively on the blood of warm‑blooded hosts that share their living space. Human blood represents the optimal source for several physiological and ecological reasons.

First, human skin temperature (33–35 °C) closely matches the thermal range that stimulates bedbug feeding behavior, ensuring rapid activation of the proboscis and efficient blood uptake. Second, the composition of human blood provides a balanced mix of proteins, lipids, and carbohydrates that support the insect’s metabolism and egg production. Third, humans excrete carbon dioxide and other volatile compounds that attract bedbugs from a distance, increasing encounter rates. Fourth, the relatively thin epidermis of human skin reduces the mechanical effort required to penetrate and access the circulatory system, minimizing energy expenditure during feeding.

Key factors that make human blood preferential:

Consistent body temperature within the optimal feeding range.
Nutrient profile suitable for growth, development, and reproduction.
Strong olfactory cues (CO₂, lactic acid, skin odors) that guide host location.
Thin epidermal barrier facilitating easy proboscis insertion.

These attributes collectively explain why domestic bedbugs favor humans over alternative vertebrate hosts present in an apartment.

The Role of Carbon Dioxide in Location

Carbon dioxide released by humans and pets creates a gradient that bedbugs follow to locate a blood source. Their sensory organs detect concentrations as low as 0.01 % above ambient levels, directing movement toward the highest plume. In an apartment, this gradient forms around sleeping areas, couches, and any location where respiration occurs continuously.

Breathing zones under mattresses and pillows generate the strongest CO₂ signals.
Seating furniture occupied for extended periods produces moderate emissions.
Unoccupied rooms exhibit baseline atmospheric CO₂, offering little attraction.

Bedbugs exploit these patterns by positioning themselves near seams, cracks, and baseboards that intersect the rising plume. Understanding the spatial distribution of carbon dioxide helps predict infestation hotspots and guides targeted inspections and treatments.

The Bed Bug Feeding Process

How Bed Bugs Bite

Domestic Cimex lectularius survive by extracting blood from people who occupy the residence. They become active after darkness, when body heat and carbon‑dioxide emissions rise, guiding the insects to potential hosts.

When a bed bug contacts skin, two slender mandibles form a needle‑like proboscis. The proboscis penetrates the epidermis, and the bug injects a cocktail of saliva that contains anticoagulants to keep blood fluid and a mild anesthetic that reduces immediate sensation. Blood is then drawn upward through the same channel and stored in the insect’s expanded abdomen.

Bites typically appear in clusters of three to five punctures, often aligned in a row. Lesions emerge within minutes to hours, presenting as small, red, itchy welts. The reaction intensity varies with individual sensitivity and the amount of saliva delivered.

Key elements that determine a bite event:

Presence of a sleeping or resting person emitting heat and CO₂
Nighttime humidity levels that favor insect mobility
Proximity of the bug to the host’s exposed skin
Duration of uninterrupted feeding, usually 5–10 minutes per site

Understanding the feeding process clarifies why bed bugs target occupants during rest periods and why their bites are localized, transient, and often unnoticed until a reaction develops.

The Anticoagulant and Anesthetic in Saliva

Bedbugs locate a host by detecting carbon dioxide, heat, and movement, then pierce the skin with a specialized proboscis. During the bite, the insect injects saliva that contains two primary bioactive agents: an anticoagulant that prevents blood clotting and a local anesthetic that suppresses pain perception. These substances enable the bug to draw a continuous blood stream without alerting the host.

The anticoagulant, primarily a protein called apyrase, hydrolyzes adenosine diphosphate, disrupting platelet aggregation and maintaining fluid flow at the feeding site.
The anesthetic component, identified as a mixture of small peptides, blocks voltage‑gated sodium channels in peripheral nerves, reducing the transmission of nociceptive signals.

Together, these compounds allow domestic bedbugs to feed for several minutes, extracting sufficient blood to support growth, reproduction, and survival within an apartment environment.

Frequency and Duration of Feeding

Domestic bedbugs obtain nourishment exclusively from human blood, seeking hosts during nighttime when occupants are immobile. Their feeding cycle is driven by physiological need and environmental conditions within a dwelling.

After emerging from a molt, an adult or nymph initiates its first blood meal within 24–48 hours.
Subsequent meals occur at intervals of 3–7 days for adults, extending to 10–14 days for late‑instar nymphs.
During periods of low temperature or reduced host availability, the interval can lengthen to several weeks, allowing survival without feeding for up to 5 months in the adult stage.

Each feeding episode lasts between 3 and 10 minutes. The insect inserts its proboscis into the skin, injects anticoagulants, and ingests blood until its abdomen is distended. Feeding time shortens as the insect matures; early nymphs may require the full 10 minutes, while adults often complete a meal in under 5 minutes. The brief duration minimizes host detection and facilitates rapid retreat to hiding sites.

Alternative Food Sources (When Humans Are Unavailable)

Other Mammals

Domestic bedbugs (Cimex lectularius) obtain blood meals from any warm‑blooded mammal that is present in a residential setting. While humans are the most common host, other mammals can sustain the insects and contribute to population growth.

Typical non‑human hosts include:

Cats and dogs, which often share sleeping areas with occupants.
Small rodents such as mice and rats that may inhabit walls or storage spaces.
Ferrets, rabbits, and other small pets kept indoors.
Occasionally, wildlife that enters the building, for example squirrels or raccoons.

Bedbugs locate these hosts by detecting carbon dioxide, heat, and movement. A single blood meal provides enough protein and lipids to support egg production for several days, regardless of the host species. Consequently, the presence of multiple mammalian hosts can accelerate the rate of egg laying and increase infestation density.

Control measures must address all potential mammalian sources. This involves regular inspection of pet bedding, sealing entry points for rodents, and treating areas where animals rest. Eliminating alternative hosts reduces the frequency of blood meals and helps suppress the colony.

Birds

Domestic bedbugs (Cimex lectularius) are obligate hematophages that require warm‑blooded vertebrate blood to complete their life cycle. In residential settings, the primary source of nourishment is human blood, supplied by the occupants’ regular exposure during night‑time rest. Birds, while occasionally present in apartments as pets or occasional visitors, do not constitute a significant food source for these insects.

Key points regarding avian interaction with indoor bedbugs:

Bedbugs possess sensory mechanisms tuned to human skin temperature (≈33 °C) and carbon‑dioxide exhalation; avian body heat and respiration differ sufficiently to reduce attraction.
The morphology of avian feathers creates a physical barrier that impedes the insect’s ability to locate a bite site, unlike exposed human skin.
Laboratory studies show negligible feeding success on birds, with mortality rates rising after attempts to pierce feathered skin.
Occasional incidental feeding may occur if a bird is in close proximity to a heavily infested area, but such events do not support population growth.

Therefore, while birds can coexist in an apartment, they do not provide a viable nutritional substrate for indoor bedbugs. Control measures should focus on human‑related habitats, such as mattresses, furniture seams, and wall voids, rather than on avian occupants.

The Impact of Starvation

Domestic bedbugs in residential settings rely almost exclusively on the blood of humans and, occasionally, other warm‑blooded occupants. Their mouthparts pierce the skin, inject anticoagulants, and withdraw a meal that provides proteins, lipids, and carbohydrates essential for development and reproduction.

When access to a host is interrupted, bedbugs enter a state of starvation that triggers several physiological and behavioral responses:

Metabolic rate declines, allowing individuals to survive weeks to months without feeding.
Molting and egg production pause; females cease oviposition, reducing population growth.
Energy reserves shift toward maintenance of vital organs, depleting stored glycogen and lipids.
Activity levels drop; insects become less mobile and less likely to seek hosts.
Upon re‑exposure to a host, previously starved individuals accelerate feeding to replenish deficits, often resulting in larger blood meals.

Extended starvation can lead to increased mortality, especially in younger nymphs with limited reserves. However, the ability to endure prolonged periods without a blood source contributes to the persistence of infestations, as dormant individuals may re‑activate when occupants return or new hosts become available.

Factors Influencing Feeding Behavior

Temperature and Humidity

Bedbugs in residential units rely on human blood, and their willingness to feed is strongly linked to ambient temperature and relative humidity.

Temperatures between 22 °C and 29 °C (72 °F–84 °F) accelerate metabolism, shorten the interval between meals, and increase movement toward hosts. Below 15 °C (59 °F) activity drops sharply, and feeding may be delayed for weeks. Above 30 °C (86 °F) dehydration risk rises, prompting bedbugs to seek shelter rather than feed.

Relative humidity of 50 %–80 % maintains cuticular water balance, supporting prolonged feeding periods and egg viability. Humidity below 40 % forces rapid water loss, leading to reduced feeding frequency and higher mortality. Levels above 90 % encourage fungal growth, which can indirectly affect bedbug populations.

Practical implications:

Keep indoor temperature near the lower end of the optimal range (22 °C–24 °C) to slow metabolism.
Maintain humidity around 45 %–55 % to limit water availability without creating conducive conditions for other pests.
Monitor seasonal fluctuations; adjust heating, cooling, and dehumidification systems accordingly to disrupt feeding cycles.

Population Density

Domestic bedbugs in multi‑unit dwellings concentrate where hosts are abundant. High population density increases competition for blood meals, prompting insects to extend feeding times, shift to less preferred body zones, or feed on multiple occupants during a single night. When several individuals occupy a confined space, the probability that a bedbug will encounter a human host rises sharply, reducing the interval between meals and accelerating growth and reproduction.

Key effects of crowding on feeding behavior include:

Shortened fasting periods, leading to more frequent blood intake.
Expanded host range within the apartment, encompassing occupants of adjacent rooms.
Elevated bite incidence, because multiple bugs target the same host simultaneously.
Increased egg production, as frequent feeding supplies the protein required for oviposition.

Consequently, apartments with dense human occupancy create an environment where bedbugs can sustain continuous feeding cycles, thereby intensifying infestation levels and complicating control efforts.

Life Cycle Stage

Domestic bedbugs progress through five developmental stages, each with distinct nutritional requirements.

The egg stage is entirely dependent on the nutrients supplied by the female during oviposition; it does not feed on any external source.

Nymphal stages, numbered from first to fifth instar, require a single blood meal to molt to the next stage. After each molt, the nymph seeks a host and ingests human or animal blood, providing the protein and lipids necessary for growth.

Adult bedbugs also feed exclusively on blood. A single meal supplies sufficient energy for reproduction, digestion, and activity for several days. Adults may feed every few days to weeks, depending on host availability and ambient temperature.

Key points for each stage:

Egg: No feeding; development relies on maternal reserves.
First‑to‑fourth instar nymphs: One blood meal per molt; host species includes humans and domestic animals.
Fifth instar nymph: Requires blood before reaching adulthood; feeding pattern similar to adults.
Adult: Repeated blood meals; primary source is human occupants, but pets can serve as alternative hosts.

Understanding these feeding patterns clarifies why control efforts must target both active (nymph and adult) and dormant (egg) populations within an apartment.

Misconceptions About Bed Bug Diets

Debunking Myths About Fabric and Wood Consumption

Bedbugs in residential units obtain nourishment exclusively from the blood of warm‑blooded hosts; they do not ingest fabrics, wood, or any building materials. Their mouthparts are adapted for piercing skin and extracting circulatory fluid, a process confirmed by numerous entomological studies.

Common misconceptions:

Fabric consumption – Bedbugs lack the enzymes required to break down cotton, polyester, or upholstery fibers. Observations of damage to clothing are actually caused by feeding marks on the wearer, not by material degradation.
Wood degradation – The exoskeleton of a bedbug cannot digest lignin or cellulose. Reports of gnawed wood stem from other pests such as termites or carpenter ants, not from bedbugs.
Food source versatility – Laboratory experiments demonstrate that bedbugs survive only when a live host is present. Starvation beyond a few weeks results in mortality, regardless of available organic debris.

The biological imperative for blood drives all observed behavior. Bedbugs locate hosts through heat, carbon dioxide, and kairomones, not by detecting textile or timber cues. Consequently, control measures should focus on eliminating host access and reducing hiding places, rather than treating fabrics or wooden structures as food sources.

Why Bed Bugs are Not Interested in Food Scraps

Bed bugs are obligate blood‑feeders; their mouthparts, digestive enzymes, and metabolic pathways are specialized for extracting and processing vertebrate blood. Solid food residues do not provide the necessary nutrients, and the insects lack the physiological mechanisms to break down carbohydrates, fats, or proteins found in kitchen waste.

Key factors that deter bed bugs from consuming food scraps:

Sensory specialization – chemoreceptors respond primarily to carbon dioxide, body heat, and skin odors, not to the volatile compounds emitted by decomposing food.
Digestive limitation – the gut contains proteases and lipases tailored to hemoglobin and other blood components; it cannot efficiently process solid matter.
Moisture requirements – blood supplies the water needed for metabolism, whereas food waste often presents unsuitable humidity levels.
Ecological niche – bed bugs occupy crevices near sleeping areas where blood hosts are present, reducing exposure to kitchen debris.

Consequently, household food waste does not attract or sustain bed bug populations, even in heavily infested apartments. Their survival depends exclusively on regular blood meals from humans or other warm‑blooded hosts.