Bed bugs are small, flat, parasitic insects that feed solely on the blood of people and animals while they sleep. They are a resilient pest that can be difficult to control and eliminate. Bed bugs can survive for months without feeding and their small, flat bodies allow them to hide in tiny cracks and crevices. Understanding what allows bed bugs to stay alive can help people better control these pests.
Bed Bug Biology
Feeding Habits
Bed bugs are obligate hematophagous insects, meaning they require blood meals to survive, develop, and reproduce. They feed mostly at night when hosts are sleeping. Their bodies are flat which allows them to hide in tiny crevices and cracks during the day. At night, they emerge to feed on exposed skin, often around the face, neck, arms, and hands of people. They use their piercing-sucking mouthparts to draw blood for several minutes. After feeding, the bugs return to their hiding places. They can survive months between blood meals.
Reproduction
Female bed bugs lay between 1-5 eggs per day and 200-500 in a lifetime. The eggs are tiny, about 1 mm long, and pearl-white. They are laid in the bugs’ hiding places. Eggs hatch in about 10 days. Nymphs require at least one blood meal to molt into the next stage. There are 5 nymphal stages before reaching adulthood. Under optimal conditions, bed bugs can reach maturity in as little as 4-5 weeks. Mating occurs right after the adults molt.
Flat Bodies
A key adaptation that allows bed bugs to hide and survive is their dorsoventrally flattened bodies. Their body shape allows them to squeeze into extremely narrow spaces like cracks, seams of mattresses, and crevices. This helps them stay hidden from detection during the day and escape threats. Their flatness also provides resistance to crushing if hosts roll over while sleeping.
Resilience
Bed bugs are remarkably resilient insects in various ways:
– They can survive months without feeding. Nymphs can survive 2-3 months and adults 4-12 months without a blood meal.
– They have a broad temperature tolerance, able to survive temperatures from nearly freezing up to 113°F.
– All stages can withstand significant dehydration, losing over a third of their body weight in water loss.
– Exposure to many insecticides does not kill bed bugs immediately, giving them time to spread. They have developed resistance to various insecticide active ingredients.
– Eggs are resistant to desiccation and can remain viable for months in the environment.
– Nymphs and adults can survive being submerged underwater for several days.
Senses
Bed bugs rely heavily on their well-developed sense of smell for survival. They can detect carbon dioxide, warmth, and certain chemicals that signal a nearby host. These cues help them locate hosts in the darkness. Once on the host, hair and skin chemicals provide more cues to find prime feeding spots. After feeding, their keen senses guide them back to their harborage areas.
Where Do Bed Bugs Hide?
Understanding where bed bugs like to hide during the day is critical to controlling them. Their dorsoventrally flattened bodies allow them to squeeze into incredibly tiny spaces in their environment. Common hiding spots include:
– Cracks, crevices, and joints of beds and furniture
– Along mattress seams and tufts, under mattress labels
– Inside box springs through fabric covering
– Behind headboards and footboards
– Under loose wallpaper and paneling
– Behind picture frames and switch plates
– Inside electronics like alarms clocks and phones
– Under carpet edges against baseboards
– Inside couch and chair seams and cushions
– In clothing stored in closets and dressers
– Inside cracks in plaster and peeling paint
– Inside books and clutter around the bed
In general, bed bugs will seek out any undisturbed location that provides darkness, protection, and proximity to hosts. Clutter provides lots of great hiding spots for the bugs.
Signs of Bed Bugs
Recognizing signs of bed bugs can help detect infestations early before they grow and spread. Some key signs include:
Live Bugs
Seeing live bed bugs is an obvious sign of activity. Look along mattress seams, in box springs, behind headboards, under carpet edges and in other hiding spots. Use a flashlight to inspect cracks and crevices. Newly hatched nymphs can be as small as a pinhead. Look for all life stages – translucent eggs, tiny nymphs, and larger wingless adults.
Blood Spots and Smears
After feeding, bed bugs will leave behind blood stains from crushed bugs or excess blood in their feces. Blood spots may accumulate on sheets, mattresses, furniture, and walls. Shiny brown or red smears or tiny blood specks are a key sign.
Molts
As juvenile bed bugs grow, they shed their outer exoskeleton. The translucent, light tan exoskeletons may be left behind in hiding spots. The size of the molts gives clues to the age of the developing bugs.
Odor
Sometimes a sweet, musty odor can arise from a heavy infestation. The smell comes from the bugs’ oil secretions and waste products. However, the odor can be variable and many infestations produce no odor at all.
Bites
Some people react to bed bug bites with large, itchy welts. However, bites do not appear on all people. Reactions can take a couple days to appear and are often clustered in groups or lines. Bites alone do not confirm an infestation since bites can be caused by other pests.
Bed Bug Behavior
Understanding the predictable behavior patterns of bed bugs can aid in detection and control. Key behaviors include:
Nocturnal Activity
Bed bugs are primarily nocturnal and come out at night to feed. During daylight hours, nearly all bugs will be hiding in cracks and crevices in clusters. They exhibit peak activity in the hours right before dawn. Feeding usually lasts 5-10 minutes.
Host Searching
At night, bed bugs emerge from hiding and crawl up walls, furniture, and other surfaces in search of hosts. They are guided by warmth, carbon dioxide, and host odors. Travel distances average 5-20 feet but can be up to 100 feet to find a blood meal.
Aggregation
Bed bugs have a strong tendency to aggregate with other bed bugs once they have fed. As soon as one bug locates a suitable hiding spot, others will gather there as well, forming tightly packed groups. All stages congregate together.
Dispersal
When conditions deteriorate, such as cooling temperatures or a lack of regular host availability, bed bugs will disperse to seek out new habitats and hosts. This spreading leads to rapid population expansion and infestation growth.
Mating
Mating takes place right after feeding and is an assertive, aggressive process. Females mate about once per week, storing sperm to fertilize multiple batches of eggs. Unmated adult females may produce some infertile eggs as well.
Environmental Conditions Bed Bugs Need to Thrive
Blood Meals
Regular access to hosts for blood feeding is critical for bed bug survival and reproduction. Large populations indicate an abundant host resource. Humans are the preferred host, but bed bugs will feed on other mammals and birds in absence of people.
Temperatures
Bed bugs prefer moderate temperatures between 70-80°F. At these temperatures, bed bug activity accelerates and populations can expand rapidly. Temperatures above 100°F or below freezing will kill bed bugs, but they can survive outside these ranges for extended periods.
Harborage Sites
Access to undisturbed harborage sites with cracks and voids to allow tight aggregation is vital to bed bugs. Clutter provides the most harborage opportunities. Tidiness limits where bed bugs can hide and establishes physical barriers to movement.
Proximity to Hosts
Since bed bugs only travel moderate distances for hosts, continuous access to hosts allows populations to persist and grow. Sleeping and resting areas provide easy, short-distance access to people. Couches and chairs also provide good proximity to hosts for sofas.
Moisture
Bed bugs require a moderate balance of moisture for survival. Low humidity causes excess moisture loss, while high humidity promotes fungal growth. Ideal conditions are between 70-90% relative humidity. Harborages must provide adequate moisture balance.
What Do Bed Bugs Eat?
Bed bugs are exclusively hematophagous, meaning they feed only on blood. Human blood is their preferred food source, but they will also readily bite other mammals and birds. Some key facts about bed bug feeding include:
– Feed for about 5-10 minutes per meal, typically once per week. Will feed more frequently in high pest pressure situations.
– Use a piercing-sucking mouthpart called a proboscis to pierce skin and draw up blood.
– Bite exposed skin, often around the face, neck, arms, and hands at night while hosts sleep.
– Inject saliva while feeding which contains anesthetics to prevent detection and anticoagulants to facilitate feeding.
– Can consume over 7 times their weight in blood. Larger adults consume the most blood.
– Blood meals are necessary for nymphs to molt and for adults to lay viable eggs.
– Can survive 2-6 months without feeding, allowing them to persist when hosts temporarily leave.
– Acquire several lifetime blood meals, feeding every 5-7 days on average.
– Preferred host blood provides optimal nutrition for growth and reproduction. Will choose human over animal hosts when given a choice.
– Bite a wide range of vertebrate hosts including humans, pets, livestock, bats and birds when optimal hosts are unavailable.
How Far Do Bed Bugs Travel?
Bed bugs are very mobile and will crawl considerable distances to seek hosts and expand infestations. Typical travel distances include:
– Nightly travel of 5-20 feet from harborages to find a host.
– Up to 100 foot dispersal from heavily infested sites to new locations.
– Through wall voids and false ceilings to adjacent rooms and living spaces.
– Between adjacent apartments and hotel rooms via wire conduits, pipes and ductwork.
– Infested objects easily transport bed bugs to new areas during moves.
– On hosts’ clothing and belongings allowing transfer to cars, workplaces and more.
– Carried long distances when accidentally transported in luggage, furniture, vehicles and other items.
So while bed bugs only crawl moderate distances on their own, human activity often spreads them throughout buildings and allows long-distance dispersal. Careful inspection and monitoring for bed bugs, especially after travel, can help prevent spread.
Bed Bug Population Growth Potential
Given optimal conditions, bed bug populations can expand rapidly due to:
– High female fecundity. Each mature female can produce 200-500 eggs in her lifetime.
– Short generation time. Under peak conditions, bed bugs can complete a full life cycle in just 4-5 weeks.
– Overlapping generations. All life stages coexist continuously.
– Lack of dormancy periods. Bed bugs can mate and reproduce year-round.
– Ability to survive high pest densities due to small size.
– Tendency to aggregate which accelerates mating opportunities.
– Lack of natural predators indoors.
Studies have shown bed bug populations doubling in size every two weeks to a month. Starting from one fertilized female, a population could hypothetically exceed a quarter million bugs in just a year. However, natural limits from pesticide exposure, host grooming and environmental conditions keep growth in check. Still, optimal conditions allow bed bug numbers to rebound quickly, even after control attempts.
Bed Bug Development and Life Cycle
Eggs
– Females lay 1-5 whitish, pear-shaped eggs per day, sticking them in cracks and crevices near harborage areas.
– Over 200 eggs may be laid in a female’s lifetime.
– Tiny eggs about 1 mm long. Can sometimes see developing embryo inside.
– Eggs firmly glued in place, but easily dislodged by cleaning or rubbing.
– Hatch in around 10 days under warm conditions.
Nymphs
– Crawlers emerge and immediately seek first blood meal.
– Must feed to molt into the next nymph stage.
– Go through 5 nymphal stages, getting progressively larger with each molt.
– Appear whitish to cream colored due to translucent exoskeleton.
– Develop small wing pads in later stages.
– Average life stage duration ranges from 22-55 days depending on environment.
Adults
– After final nymphal stage, develop into winged adults about 4-5 mm long.
– Adults must feed before mating and egg production occurs.
– Females lay eggs continuously once mated. Life span averages 6-12 months.
– Adult bodies brown to red-brown in color once fed.
– Can survive over a year with intermittent feeding.
Conclusion
Bed bugs are remarkably well adapted for survival. Their resilience, reproductive capacity and hardy biology make them challenging pests to eliminate once established in human living spaces. By understanding their essential survival needs, habits and capabilities, people can target management strategies to control infestations and prevent further spread of these pervasive parasites. Public awareness and proper identification remain key defenses against proliferation of these blood-feeding pests in human environments. Continued research into bed bug biology and ecology will uncover new ways to stem population growth and restrict their impacts.