Bed Bugs09/24/2012 03:15
Bed bug infestations are increasingly common, as our world gets denser and faster, but there are certain steps you can take to prevent bed bugs from infesting your home. When bed bugs are present, they can be controlled. On this site you will learn more about how they live, thrive, move around and how to recognize and inspect for their presence, steps to take to prevent them from infesting your home, how to safely rid your home of bed bugs if they do occur, and also how to select and work with a pest management professional.
It's always a good idea to try to identify the source of transmittal of bed bugs, so this portal can be eliminated. Given the fact that bed bugs can live without a source of food for well over a year, makes process of identifying the source somewhat difficult.
What do bed bugs look like?
Adult bed bugs are about 1/4 inch long, but can flatten themselves to fit into small cracks .
They are big enough to be easily seen, but often hide in cracks in furniture, floors, or walls. They are more of the nocturnal pest, and mostly will prefer co become more active at night, but can also be seeing during a day if opportunity arises. Bed bugs feed on blood and will habit ate in the area where it's food source is commonly present, i.e., bed, couch, chairs, but will hide also in the nearby wooden or plastic furniture and picture frames, under wall paper, inside electric outlets, etc.,
Bed bugs must feed on blood in order to reproduce and grow. Sticky eggs are laid by a female bed bug and once hatched go through five stages of growth
Bed bug behavior and biology
Article by Dini M. Miller, Ph.D., Department of Entomology, Virginia Tech
Andrea Polanco, Department of Entomology, Virginia Tech
The bed bugs that are infesting homes today are the descendents of cave dwelling bugs that originally fed onthe blood of bats. When humans began living in the caves, the bugs began feeding on humans. Later, whenhumans moved out of the caves and started theiragricultural civilizations, the bugs moved with them. Since that time, humans have carried bed bugs allover the world. Bed bugs belong to a family of insects called Cimicidae. All members of this family feed exclusively on blood. The common bed bug (Cimex lectularius) has five developmental life stages. Each immature life stage (called nymphs or instars) must take a blood meal in order to develop into the nextlife stage. Because bed bugs, like all insects, have their skeleton on the outside of their body (exoskeleton) they have to shed their exoskeleton in order to grow larger. This shedding of the exoskeleton is called molting. A bed bug nymph must take a blood meal to molt successfully. After growing through five instar molts, the bed bug becomes an adult. Adult bed bugs, both male and female, must also take regular blood meals to reproduce. The total development process from and egg to an adult can take place in about 37 days at optimal temperatures (>72° F). Adult bed bugs have a life span of nearly one year depending on regular access to blood meals and favorable temperatures.
Bed bugs have a cryptic lifestyle, meaning they spend the majority of their time hiding together in cracks and crevices where they will not be seen or disturbed. However, they become active at night, between midnight and 5:00 am. It is during this time, when the human host is typically in their deepest sleep, that bed bugs like to feed. Bed bugs are known to travel many yards to reach their human host. Bed bugs are attracted to CO2 produced by the host exhalations, and they are also attracted to body heat. However, bed bugs are only able to detect these host cues over short distances (about 3feet away for CO2 and even less for heat). It is not well understood how bed bugs hiding in a closet are able to find a host located in a bed across the room. However, bed bugs are able to move very quickly, and it is thought that they do a lot of wandering around before they are able to locate their food. Ideally, most bed bugs would like to aggregate near the host’s bed, on the mattress or in the boxsprings, when they are not feeding. However, this is not always possible in heavy infestations where bed bugs are crowded and many bed bugs have to seek refuge at distances several yards from the host. Once a bed bug finds the host, they probe the skin with their mouthparts to find a capillary space that allows the blood to flow rapidly into their bodies. A bed bug may probe the skin several times before it starts to feed. This probing will result in the host receiving several bites from the same bug. Once the bed bug settles on a location, it will feed for 5-10 minutes. After the bed bug is full, it will leave the host and return to a crack or crevice, typically where other bed bugs are aggregating. The bed bug will then begin digesting and excreting their meal. Bed bugs usually feed every 3-7 days, which means that the majority of the population is in the digesting state, and not feeding most of the time.
After feeding, adult bed bugs, particularly the males, are very interested in mating. Cimicid bugs have unique method of mating called traumatic insemination. This mating behavior is considered traumatic because the male, instead of inserting his reproductive organ (paramere) into the female genitalia, he literally stabs it through her body wall into a specialized organ on her right side, called the Organ of Berlese. The male sperm is released into the female’s body cavity, where over the next several hours it will migrate to her ovaries and fertilize her eggs.
The traumatic insemination stabbing creates a wound in the female’s body that leaves a scar. The female’s body must heal from this wound and consequently, females are known to leave aggregations after being mated several times to avoid any further abuse. Studies have shown that the process of healing from traumatic insemination has a significant impact on the female’s ability to produce eggs. In fact, females that
mate only once, and are not subjected to repeated stabbings by the male will produce 25 percent more eggs than females that are mated repeatedly. In practical terms, this means that a single mated female brought into a home can cause an infestation without having a male present, as long as she has access to regular blood meals. The female will eventually run out of sperm, and will have to mate again to fertilize her eggs. However, she can easily mate with her own offspring after they become adults to continue the cycle.
The number of egg batches a female will produce in her lifetime is dependent on her access to regular blood meals. The more meals the female can take the greater the number of eggs she will produce. For example, the average adult female will live about one year. If she is able to feed every week, she will produce many more eggs in that year than if she is able to feed only once a month.
A female bed bug will produce between 1- 7 eggs per day for about 10 days after a single blood meal.
• She will then have to feed again to produce more eggs.
• A female can produce between 5 and 20 eggs from a single blood meal.
• The number of male and female eggs produced is about the same (1:1 ratio).
• A single female can produce about 113 eggs in her whole life.
• Eggs can be laid singly or in groups. A wandering female can lay an egg anywhere in a room.
• Under optimal conditions, egg mortality is low and approximately 97% of the bed bug eggs hatch successfully.
• At room temperature (>70° F), 60 percent of the eggs will hatch when they are 6 days old; >90 percent will have hatched by the time they are 9 days old.
• Egg hatch time can be increased by several days by lowering ambient temperature (to 50° F).
• Due to the large numbers of eggs a female can produce under optimal conditions (temperatures >70° F but < 90° F, and in the presence of a host), a bed bug population can double every 16 days.
Nymph Development Time
The time it takes any particular bed bug nymph to develop depends on the ambient temperature and the presenceof a host. Under favorable conditions, such as a typical indoor room temperature (>70° F), most nymphs will develop to the next instar within 5 days of taking a blood meal. If the newly molted instar is able to take a blood meal within the first 24 hours of molting, it will remain in that instar for 5-8 days before molting again. At lower temperatures (50° F – 60° F), a particular instar may take two or three days longer to molt to the next life stage than a nymph living at room temperature. However, if a bed bug nymph does not have access to a host, it will stay in that current instar until it is able to find a blood meal, or it dies. The time for a bed bug to develop from an egg, through all five nymphal instars, and into a reproductive adult is approximately 37 days. Even under the best conditions some bed bug nymphs will die prior to becoming adults. The first instars are particularly vulnerable. Newly hatched nymphs are exceptionally tiny and cannot travel great distances to locate a host. If an egg is laid too far from a host, the first instar may die of dehydration before ever taking its first blood meal. However, laboratory studies have found that overall bed bug survivorship is good under favorable conditions, and that more than 80 percent of all eggs survive to become reproductive
Adult Bed Bug Life Span
The most recent studies indicate that a well-fed adult bed bug held at room temperature (>70° F), will live between99 and 300 days in the laboratory. Unfortunately, we do now know exactly how long a bed bug might live in someone’shome or apartment. No doubt it will be at least several months. However, conditions are usually more challenging for the bed bugs living in human dwellings than they are in the laboratory (finding food, fluctuations in temperature and humidity, the presence of insecticides, avoiding being crushed, etc.) and these conditions will have a negative impact on bed bug survival. A recent laboratory study has shown that starvation has a negative impact on bed bug survival. This modern study contradicts European studies conducted in the 1930s and 40s, when it was determined that bed bugs could survive periods
of starvation lasting more than one year. While this may have been true for individual bed bugs in the UK living at very low temperatures (< 40° F; because of no central heating); modern bed bugs collected from homes in the United States do not live that long. On average starved bed
bugs (at any life stage) held at room temperature will die within 70 days. Most likely these bed bugs are dying of dehydration, rather than starving to death. Because bed bugs have no source of hydration other than their blood meal, dehydration is the greatest natural threat to their survival while living in the indoor environment. In fact, one of the reasons that bed bugs pack themselves so tightly into small cracks and crevices is so that they can maintain a microhabitat of favorable temperature and humidity, thus increasing their ability to survive periods of starvation.
Bed Bugs that are Resistant to Insecticides
The lifecycle data presented in this publication is based on research conducted using bed bugs collected from apartments within the state of Virginia. These populations have documented resistance to pyrethroid insecticides. Laboratory studies have indicated that resistant bed bugs have a shorter developmental time (several days), shorter life spans and lower levels of egg production than bed bugs that are not resistant to insecticides. At the time of this writing, practically all natural bed bug populations collected in Virginia have been found to be a least somewhat resistant to pyrethroid insecticides.