What do bedbugs feed on in an empty apartment?

Understanding Bed Bug Survival

The Bed Bug Diet «Blood Meal»

Human Blood as Primary Food Source

Bedbugs survive in unoccupied units by locating human blood, which remains their exclusive nutrient. Even in the absence of a resident, these insects can persist by feeding on trace amounts of blood left on surfaces such as mattress seams, pillowcases, and upholstered furniture. The protein and lipid content of human hemoglobin supplies the energy required for development, molting, and reproduction.

Key aspects of blood as a food source include:

Nutrient composition: Hemoglobin provides iron, amino acids, and fatty acids essential for insect metabolism.
Accessibility: Small blood residues persist after cleaning, enabling bedbugs to locate meals without a host present.
Survival strategy: Females can lay eggs after a single blood meal, allowing the population to maintain itself despite limited feeding opportunities.

Bedbugs detect blood through heat and carbon‑dioxide cues. In a vacant apartment, residual warmth from recent occupancy and lingering CO₂ from human activity guide them to the remaining blood traces. Once a meal is obtained, the insect can survive for several months, extending the infestation period until a new host arrives.

Other Mammalian Blood Sources

Bedbugs are obligate hematophages that can obtain nourishment from any warm‑blooded mammal. In the absence of human occupants, domestic animals provide the most readily available alternative.

Dogs and cats frequently share sleeping areas with bedbugs, offering blood meals that sustain development and reproduction.
Small rodents such as mice and rats may infiltrate vacant units, especially through cracks and gaps, and serve as occasional hosts.
Occasionally, wildlife such as squirrels, raccoons, or opossums enters buildings in search of shelter, delivering additional blood sources.

The nutritional composition of mammalian blood is sufficiently similar across species to support the insect’s life cycle. Bedbugs feeding on non‑human hosts exhibit comparable engorgement volumes and egg‑laying rates, provided that host availability is regular. However, intermittent access to alternative mammals can extend survival periods, allowing the population to persist until human re‑occupation occurs.

Control measures that focus solely on human exposure may overlook these secondary hosts. Effective management in vacant apartments should incorporate inspection and treatment of pet bedding, rodent control, and sealing of entry points to limit wildlife intrusion.

Factors Affecting Bed Bug Longevity

Environmental Conditions

Bedbugs in a vacant dwelling rely on ambient factors to locate a host and sustain themselves until a blood meal becomes available. Their survival hinges on specific environmental parameters that influence metabolic rates, activity periods, and the likelihood of encountering a human presence.

Temperature: Optimal range 21–27 °C (70–80 °F). Within this band, metabolism operates efficiently, allowing longer intervals between feeds. Temperatures below 15 °C (59 °F) suppress activity and extend survival without feeding; temperatures above 30 °C (86 °F) increase metabolic demand, shortening the period they can endure without a host.
Relative humidity: Preferred 40–60 %. Adequate moisture prevents desiccation of the cuticle and preserves egg viability. Humidity below 30 % accelerates water loss, leading to higher mortality in the absence of a blood source.
Carbon dioxide concentration: Elevated CO₂ levels signal the presence of a living host. In an empty apartment, background CO₂ remains low, reducing the stimulus for host‑seeking behavior. Minor fluctuations from human activity in adjacent units can trigger movement toward potential entry points.
Light cycles: Bedbugs are nocturnal, responding to darkness for feeding activity. Continuous illumination disrupts their circadian rhythm, diminishing the drive to search for a host. Dim or intermittent lighting mimics natural conditions, encouraging periodic movement.
Airflow and ventilation: Stagnant air retains heat and humidity, creating microhabitats favorable for prolonged survival. Strong drafts disperse these conditions, potentially dispersing insects but also reducing the microclimate stability needed for extended fasting periods.

These environmental conditions collectively determine how long bedbugs can persist in an unoccupied apartment and their readiness to feed when a host reappears. Managing temperature, humidity, and ventilation can influence their survivability during vacancy periods.

Developmental Stages and Feeding Frequency

Bedbugs survive on blood, even when a residence is unoccupied. Their ability to locate a host depends on the presence of humans or other warm‑blooded animals; in a vacant apartment they remain dormant until a suitable source appears.

The life cycle consists of six stages: egg, five nymphal instars, and adult. Only the mobile stages require blood meals. Eggs are deposited in clusters and hatch within 6–10 days under typical indoor temperatures. Nymphs progress through successive molts, each requiring a blood meal to initiate the next stage.

First instar: feeds every 3–5 days; blood volume is minimal, sufficient for growth to the second instar.
Second and third instars: feed every 5–7 days; each meal provides nutrients for molting and development.
Fourth and fifth instars: feed every 7–10 days; meals become larger, supporting reproductive organ development.
Adult: feeds every 5–10 days; frequency varies with host availability, temperature, and metabolic demand. Adults can survive several months without a meal, extending the period of dormancy in an empty dwelling.

Feeding frequency declines as the insect matures, reflecting increased blood storage capacity and reduced metabolic rate. In the absence of a host, nymphs and adults enter a quiescent state, extending the interval between meals to the maximum tolerated duration. This physiological flexibility allows bedbugs to persist in vacant apartments until a new occupant provides a blood source.

Bed Bugs in Vacant Apartments

The Illusion of an «Empty» Apartment

Residual Human Presence

Bedbugs survive in vacant dwellings by exploiting the minute biological remnants left by previous occupants. These remnants, collectively referred to as residual human presence, provide the insects with occasional sources of nourishment and cues for locating hidden hosts.

Key components of residual human presence that support bedbug survival include:

Dried blood meals stored within the insects’ gut, sustaining them for several months without a new feed.
Microscopic skin flakes and hair shafts that retain trace amounts of blood and other organic compounds.
Sweat residues and sebum left on fabrics, furnishing proteins and lipids that can be ingested when the insects probe surfaces.
Urine stains and other bodily fluids that contain nitrogenous compounds, occasionally consumed by nymphs.

In the absence of regular blood meals, bedbugs rely on the longevity of their internal reserves, entering a quiescent state when external nutrients are scarce. They remain responsive to carbon‑dioxide plumes, body heat, and vibrational cues generated by occasional human entry, allowing them to opportunistically feed on transient hosts. This combination of stored nourishment and exploitation of residual biological material enables bedbugs to persist in empty apartments for extended periods.

Alternative Hosts in Unoccupied Spaces

Bedbugs are obligate hematophagous insects, meaning they require blood for development and reproduction. In a vacant dwelling, the primary source—human occupants—is absent, so the insects must locate alternative hosts to sustain their life cycle.

Potential alternative hosts include:

Small mammals such as mice, rats, and squirrels that may enter through cracks or vents.
Birds that roost in attics, eaves, or open windows, providing a readily accessible blood meal.
Domestic animals like stray cats and dogs that occasionally wander into unoccupied units.
Larger insects, notably cockroaches, whose hemolymph can support short-term feeding.
Conspecifics; under extreme starvation, bedbugs may engage in cannibalism, consuming the hemolymph of dead or weakened individuals.

When none of these sources are available, bedbugs rely on physiological adaptations that allow prolonged fasting. Metabolic rates decline, and energy reserves stored in the fat body sustain the insect for several months. During this period, the insects remain hidden in crevices, maintaining a low-activity state until a suitable host reappears.

The presence of alternative hosts in empty apartments therefore determines the duration of infestation. Access points that permit rodents, birds, or other vertebrates to enter the space increase the likelihood of continued bedbug survival, while strict exclusion of such fauna can force the population into dormancy or eventual mortality.

Bed Bug Survival Without a Host

Prolonged Starvation Capabilities

Bedbugs are obligate blood feeders; without a host they survive solely on internal reserves. Their metabolism slows dramatically when food is unavailable, allowing entry into a quiescent state that conserves energy.

Survival without a blood meal depends on temperature, humidity, developmental stage, and prior nutritional status. Under moderate indoor temperatures (20‑25 °C) and relative humidity above 50 %, adult bedbugs can endure for 4–6 months. Cooler environments (15 °C) extend survival to 6–12 months, while warm, dry conditions reduce it to 2–3 months. Nymphs, especially early instars, die more quickly, typically within 1–2 months under the same conditions.

Temperature: lower temperatures lengthen starvation endurance; higher temperatures shorten it.
Humidity: high humidity slows desiccation, supporting longer survival.
Life stage: adults survive longest; later‑instar nymphs persist longer than early instars.
Feeding history: individuals that have recently consumed a large blood meal retain enough reserves to survive longer than those that have been fasting for weeks.

These prolonged starvation capabilities enable bedbugs to remain hidden in vacant apartments for months, reactivating when a new occupant arrives. Effective pest‑management programs must therefore include monitoring and treatment before re‑occupation, rather than assuming vacancy eliminates the infestation.

Dormancy and Diapause Mechanisms

Bedbugs in a vacant dwelling rely on physiological strategies rather than alternative food sources to persist until a host returns. Their survival hinges on two related states: dormancy and diapause.

During dormancy, insects reduce metabolic activity to conserve energy. Bedbugs achieve this by lowering respiration rates, decreasing body temperature, and limiting movement. Energy reserves stored as lipids and glycogen sustain the organism for weeks or months without blood meals. The insects can enter a quiescent phase after a single feeding, remaining inactive until environmental cues—temperature, humidity, or carbon‑dioxide levels—signal the presence of a suitable host.

Diapause represents a hormonally regulated, seasonally timed version of dormancy. Photoperiod and temperature shifts trigger the release of diapause‑inducing hormones, which suppress development and reproduction. In the diapause state, bedbugs extend their fasting period dramatically, often surviving several months. The state is reversible; rising temperatures or increased host‑derived cues reactivate feeding behavior and resume the reproductive cycle.

Key physiological adjustments that enable prolonged fasting include:

Suppression of digestive enzyme production, preventing unnecessary protein breakdown.
Up‑regulation of stress‑response proteins that protect cellular structures during nutrient scarcity.
Accumulation of cryoprotectants and antioxidants to mitigate oxidative damage.

When a host re‑enters the apartment, bedbugs detect carbon‑dioxide and heat, exit dormancy or diapause, and resume blood‑feeding. No alternative food sources are utilized; survival depends entirely on these adaptive metabolic states.

Implications for Pest Control

Importance of Thorough Inspection

A meticulous visual survey of a vacant unit reveals the locations where bedbugs may survive and obtain blood meals. Without occupants, insects hide in wall voids, mattress seams, baseboard cracks, and behind electrical outlets, waiting for occasional human intrusion. Detecting these sites prevents misinterpretation of the absence of visible insects as an indication that the infestation has ended.

A systematic inspection supplies reliable evidence of:

Live specimens or exuviae in concealed areas
Fecal spots, darkened stains, or shed skins on fabrics and furniture
Small, transparent eggs attached to seams or crevices

Accurate identification of these signs guides targeted treatment, reduces the risk of resurgence, and limits unnecessary chemical applications. By documenting the exact harborages, pest‑management professionals can prioritize interventions, monitor progress, and verify eradication after remediation.

In summary, thorough inspection delivers the factual basis needed to assess feeding potential, confirm infestation status, and implement effective control measures in an empty dwelling.

Strategies for Eradication in Vacant Units

Bedbugs can survive for extended periods without a host, relying on stored reserves and occasional opportunistic feeding. In vacant apartments, the lack of regular blood meals reduces population growth but does not eliminate the infestation, making proactive eradication essential.

Effective control in unoccupied units includes the following actions:

Conduct a thorough visual inspection, focusing on seams, mattress tags, baseboards, and electrical outlets where insects hide.
Apply targeted heat treatment, raising interior temperatures to 50‑55 °C (122‑131 °F) for a minimum of four hours to ensure mortality of all life stages.
Deploy residual insecticide sprays or dusts (e.g., silica gel, diatomaceous earth) in cracks, crevices, and voids inaccessible to heat.
Install interceptors under furniture legs and monitor traps to detect residual activity during the vacancy period.
Seal entry points, including gaps around pipes, vents, and wall penetrations, to prevent re‑infestation from adjacent units.
Perform a comprehensive vacuuming of all surfaces, immediately disposing of the collected material in sealed bags.
After treatment, schedule a post‑vacancy inspection before re‑occupancy to verify the absence of live specimens.

Combining these measures creates a layered approach that addresses both immediate elimination and long‑term prevention, ensuring the unit remains free of bedbugs when tenants return.