BED BUGS (CIMEX LACTULARIUS): CHARACTERISTICS, HABITAT, TYPES, REPRODUCTION - BIOLOGY - 2025

The bedbug (Cimex lectularius) are a kind of insects Cimicidae family. They were described for the first time in 1758 by the famous Swedish naturalist Carlos Linnaeus and it is one of the most widely distributed species in the world.

This insect is responsible for major infestations, mainly in homes, schools, hotels, and nurseries. Many times it is difficult to eradicate this pest. However, if the necessary measures are taken, complementing the use of pesticides with the protection of the sites it attacks, it is possible to eliminate it.

Cinex lactularius specimen. Source: Michael J. Raupach, Lars Hendrich, Stefan M. Kuchler, Fabian Deister, Jérome Moriniére, Martin M. Gossner / CC BY (https://creativecommons.org/licenses/by/4.0)

characteristics

From the most general point of view, Cimex lectularius is a multicellular eukaryotic organism. This has to do with the characteristics of your cells, which have a cell nucleus and are also specialized in specific functions.

They are triblastic, coelomate and protostome insects. These characteristics are related to its embryonic development. During this, the three known germ layers are present: ectoderm, mesoderm and endoderm, from which all the organs and structures of the animal originate.

They have an internal cavity called the coelom and are protostome, because both the anus and the mouth are formed from a structure known as the blastopore.

By drawing an imaginary line along the longitudinal axis of the insect, two exactly equal halves are obtained, which allows us to affirm that they have bilateral symmetry.

Its reproduction is sexual, with internal fertilization and indirect development. They are also oviparous.

They are insects with nocturnal habits, which feed on the blood of mammals such as humans and bats, as well as birds such as chickens.

Taxonomy

The taxonomic classification of Cimex lectularius is as follows:

• Domain: Eukarya
• Animalia Kingdom
• Phylum: Arthropoda
• Class: Insecta
• Order: Hemiptera
• Suborder: Heteroptera
• Family: Cimicidae
• Genus: Cimex
• Species: Cimex lectularius

Morphology

Cimex lectularius is a small insect that barely reaches 5mm in length and is reddish-brown in color. Likewise, they have three pairs of articulated legs.

On their head they have a pair of antennas, each one made up of four pieces. In addition to this, they have two large eyes and a proboscis that allows it to suck blood and inoculate substances to its victim.

Its body has an oval and flattened shape. There is some sexual dimorphism. The female is larger than the male and in the fifth segment of the abdomen it presents a cleft, which corresponds to a structure called spermatolega, which is used for fertilization.

Cimex lactularius. Its legs and antennae are observed. Source: Louis-Marie Poissant / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

In the case of males, on the abdomen they have a small but robust nail-shaped extension, the copulatory organ that it uses to fertilize the female.

Habitat and distribution

Cimex lactularius is an animal that is widely distributed throughout the world geography.

Because they feed on the blood of some warm-blooded animals, including humans, the places where they are found is where there is an abundant source of food.

In this sense, it is possible to find it inside houses, specifically in places where people tend to lie down or sit for long periods of time.

Of all those places, the favorite for Cimex lactuarius are mattresses. They are usually hidden inside these and in their seams. Likewise, large numbers of insects have also been found in places such as behind baseboards or behind wallpaper.

While it is true that these insects can infest any type of home, the reality is that they are generally associated with poor hygiene conditions. This is why it is more common to find them in homes where conditions of poor hygiene, poverty and overcrowding prevail.

It is important to note that these insects are nocturnal, that is, they come out to feed at night. This implies that during the day they prefer to remain hidden, in places where the light does not reach, such as some cracks, crevices and inside mattresses.

Classification (types)

There are other species of bed bugs that live in different regions of the planet and have different animals as their hosts. Here are a few:

Cimex hemipterus

It is known as “tropical bed bug”. As their name indicates, they are suitable to live in tropical environments where the temperature and humidity are higher.

Due to its taxonomic proximity to the common bedbug, it shares a wide variety of aspects, such as diet, habits and genetics.

It is common to find it in homes, since its main source of food continues to be humans (their blood). Likewise, specialists in the field affirm that this bed bug is also capable of parasitizing other animals such as birds and bats.

Cimex pilosellus

It is also known as "bat bug", because they feed mainly on this mammal. However, if it deserves it, it can also feed on human beings.

It is characterized by having a slightly longer head than that of the rest of the bed bugs. In addition, its body is dark in color (black or brown) and has some lighter colored spots on its surface.

Haematosiphon inodora

It is known as the "Mexican chicken bug" because it infects these birds and feeds on their blood. If its presence is not detected in time, it can become a large pest that can be very difficult to eradicate.

Leptocimex boueti

This type of bed bug also feeds on bat blood. It is found mainly on the African continent. Anatomically it is very similar to the common bedbug, but if it is observed microscopically, it can be distinguished that it has marginal hairs on the thorax that are longer than those of other species of bedbugs.

Reproduction

The type of reproduction of bed bugs is sexual, which means that there is a fusion of sex cells or gametes (eggs and sperm). Furthermore, their development is indirect, so that during their life cycle, they go through a series of larval stages.

The reproductive cycle begins with the search for the female by the male. Now, taking into account that these insects are nocturnal animals, the search is made by groping.

The way to distinguish a male from a female is by feeling their size. The females are larger because they are full of the blood with which they have fed. However, males often make mistakes and end up riding another male.

Fertilization

Once they find the female, they climb on it and fertilization occurs. In this species of insects there is a very interesting phenomenon known as traumatic insemination.

This consists of the male piercing the wall of the female's body with his copulatory organ to deposit the sperm inside. It is important to note that, as its name indicates, this type of fertilization is very traumatic for the female, and can even end in death, either by perforation of an organ such as the intestine or because the wound caused by the male becomes infected..

The sperm reaches the ovaries and is stored there in a structure known as the seminal conceptculum. Sperm can remain stored for up to 50 days, the maximum time it remains viable. After this it degenerates and the female must mate again.

Eggs

When the eggs are fertilized, the female proceeds to lay them. Eggs are characterized by adhering to the surface on which they are deposited and take an average of 15 days to hatch.

It should be noted that the survival of the eggs, as well as their hatching, is determined by favorable conditions, both temperature and humidity.

When the eggs hatch, an immature individual comes out of them, known as Nymph 1. This is the first of the five larval stages that these insects present.

Larval stages

Between each stage there is a molt and, in order to molt, it is essential that the nymph feed entirely on blood. As it goes through the different stages, its size increases. The whole process can take up to 1 month. However, it is highly dependent on food availability and temperature.

Finally, after the fifth larval stage, the last molt occurs and the adult individual emerges. It is important to mention that this is a much darker color than the nymphs. The female is fertile only in her adult stage.

Feeding

Bed bug feeding. Source: AJC1 from UK / CC BY-SA (https://creativecommons.org/licenses/by-sa/2.0)

Bed bugs are nocturnal. This implies that they feed mainly at night, especially in the early morning. However, this is not exclusively so, but can also be fed at other times of the day, if the opportunity presents itself.

These animals are hematophagous, that is, they feed on the blood of animals, especially humans. His oral appliance is adapted for this purpose, since it is made up of two very thin and hollow extensions that are inserted into the victim's skin.

Each of these tubes has a different function. Through one of them she inoculates her saliva, in which certain substances that have an anesthetic function are dissolved to prevent the victim from feeling the bite. Through the other tube, it sucks the blood that will serve as food.

The feeding process lasts several minutes and the person notices the bite long after, even hours later. Bed bugs feed, on average, every 10 days or so.

Infestation

Infestation can be defined as the process by which a home, hotel or school, among others, is invaded by a population of bed bugs that settle there and begin to cause harm to those who live in such place.

The ways in which this can occur are very varied. For example, it may be the case that bed bugs are found in some furniture (sofa, chair) and are introduced into the house. It may also happen that an inhabitant has been in a place that is infested with bed bugs and these have gotten on their clothes or skin. There are extreme and rare cases in which pets act as a vehicle to transport bed bugs.

Now, it is important to know which are the favorite places for bed bugs to hide, since when an infestation is detected, it is where you must first check.

Due to their anatomy, bed bugs can hide in very small places, from which they come out at night to feed. The specialists state that they usually stay in the vicinity of their victim, in order to be able to feed themselves calmly when she sleeps.

Detecting the presence of bed bugs in houses is somewhat difficult, since during the day they are hidden in their dens. However, there are some indications to suspect an infestation.

The first of these are the bites that appear on the skin of the victims. As already said, people find out hours later. However, seeing that you have bites and that this is repeated day by day, they may begin to investigate until they find the insects.

Likewise, when there is a high number of bed bugs, a certain characteristic smell can be perceived, which is due to the insects themselves, but also to the residues that remain after each molt. For knowledgeable people, it is really easy to tell that there is an infestation just by smelling the smell.

Biologic control

When a bed bug infestation is detected, the measures that must be taken for its total eradication are multiple and range from the use of biological agents such as pesticides, to the total isolation of artifacts and sites where bed bugs are common.

Of course, there are professionals specialized in containing and eliminating these types of pests. One of the techniques is to raise the temperature of the rooms up to 50 ° C for about an hour and a half. This will kill the insects in complete safety.

Regarding the use of biological agents to eliminate insects, it is something that is not highly recommended. This is because those that are mainly used, such as the so-called pyrethroids, have harmful and harmful effects on people.

In this sense, other chemical compounds are also used, such as boric acid, piperonyl butoxide and sulfuryl fluoride, among others. It is extremely important to follow the instructions and recommendations when using any of these chemicals.

There are also other measures that can be taken at home, such as covering mattresses and furniture with insulating plastic, vacuuming each room daily, especially those in which the pest has been detected and washing clothes with hot water, at approximately 60 ° C.

If these guidelines are followed, the bed bug infestation can be completely eradicated. It is recommended to be aware of the habits of the people who live in the house, to avoid reinfection.

References

1. Brusca, RC & Brusca, GJ, (2005). Invertebrates, 2nd edition. McGraw-Hill-Interamericana, Madrid
2. Curtis, H., Barnes, S., Schneck, A. and Massarini, A. (2008). Biology. Editorial Médica Panamericana. 7th edition.
3. Goddard, J. and DeShazo, R. (2009). Bed bugs (Cimex lectularius) and clinical consequences of their bites. Journal of the American Medical Association 301 (13).
4. Hickman, CP, Roberts, LS, Larson, A., Ober, WC, & Garrison, C. (2001). Integrated principles of zoology (Vol. 15). McGraw-Hill.
5. Pinto, L., Kraft, S. and Cooper, R. (2007). Bed Bug Handbook: The Complete Guide to Bed Bugs and Their Control. Mechanicsville, Maryland: Pinto & Associates.
6. Wang, C., Saltzmann, K., Chin, E. and Bennett, G. (2010). Characteristics of Cimex lectularius (Hemiptera: Cimicidae), Infestation and Dispersal in a High-Rise Apartment Building. Journal of Economic Entomology. 103 (1).