Many scientists believe that bed bugs don’t have good vision. They even state that bed bugs can be blind. The scientists also suggested that bed bugs find their hosts and food sources by using random search. However, entomologists do not believe that this is the truth. Bed bugs don’t use random searches to look for food.
Bed Bugs have an underdeveloped vision, that is not completely understood. But they are able to have different responses to colors and vertical objects. Bed Bugs can also differentiate particular objects in dark conditions. Their vision supports orientation and the search for food.
As bed bugs find their hosts in the night, it is generally thought that they mainly use cues such as heat and carbon dioxide to get to their food sources. The role of vision in bed bugs is not completely understood and researched by scientists. What we definitely know is their excellent sense of smell and identifying the cues, such as pheromones, carbon dioxide, and kairomones.
Bed bug vision: how do they see?
Bed bugs do have compound eyes consisting of several ommatidia (single receptors / single eyes) that vary in number and appearance. The tropic bed bug eye consists of 52 ‘single eyes’ compared to 5.000 of the common bee eye. The low number of receptors implies a low resolution in the bed bug vision.
Bed bugs do also lack ocelli – common additional eyes in insects with a retina and thousands of receptor cells. Their vision solely depends upon the small compound eyes with the few ‘single eyes’.
Bed bugs show sensitivity to lighter conditions as they try to avoid light and look out for darker places. This negative phototaxis is very strong and provided through their compound eyes.
The bed bugs are able to have different responses to colors, vertical objects, etc. The research has shown that bed bugs prefer dark colors, like black and red, from other colors, like yellow, green, blue, and white. A device with black and red colors used for the exterior surface was more appealing to bed bugs than the one with white color.
Also, the research showed that bed bugs have strong orientation behaviors towards vertical objects. This explains why they can live in walls, on sides of the mattress, etc. The scientists determined that bed bugs can detect colors and vertical objects in a very poorly lighted area. However, they are not able to do so in complete darkness.
Moreover, the bed bugs have certain texture preferences as well. They prefer dyed tape compared to painted plastic. The results of the research have shown that textures, colors, and the presence of vertical objects affect bed bug’s search for a host and overall behavior. It’s also suggested that bed bugs may use the combination of vision, reception of chemicals, and smells to seek the food.
There are certain features in bed bug’s eye morphology that differentiate them from the tropic bed bugs. Also, the researchers have found that male bed bugs are more responsive than female bugs.
Bed bugs are not social insects like, for example, bees, ants, and termites. They usually seek out places in crevices close to their main food source, blood. Over time, the number of bed bugs will drastically grow, sometimes in the hundreds or even thousands.
Can bed bugs see in the dark?
Bed bugs are able to differentiate colors and vertical objects in the dark. However, it should not be complete darkness because then they can’t determine the object. The bed bugs are nocturnal insects, meaning they are the most active at night. It’s dark in the night; however, it’s not complete darkness, so bed bugs can easily go on a hunt.
The bed bugs generally prefer to do their work in the night when the host is asleep. This makes it possible for the bed bugs to feed to the good food source without any interruptions from the human host.
However, this does not mean that bed bugs can’t feed during the day or in the morning. In fact, if they haven’t eaten in a long time and food is scarce, bed bugs will feed as soon as they find the host.
Bed bugs also use visual cues to find their hosts; that’s why the areas where they live are not too dark and not too light. They hide in hard-to-reach places throughout the day and avoid light places during the night. As mentioned above, they use additional cues, such as carbon dioxide, warmth, and moisture, to find their hosts.
These bugs feed on the areas of humans that are usually exposed, such as the face, neck, arms, and hands. Humans don’t feel the bites of bed bugs, as bed bugs inject certain anticoagulants and anesthetic through their saliva. This leads to an allergic reaction on the skin in the form of a colorless welt or lump at the location of the bite.
After they’re done feeding, bed bugs defecate semisolid and sticky materials. These materials leave reddish-black spots on mattresses or nearby furniture. If you see something like that on your bed or mattress, it’s a direct sign of bed bugs. These spots have an odor as well.
Bed bugs also prefer to live on wood, paper, and fabric surfaces. However, they can also live on many other surfaces like stone, metal, or even plaster. They can quickly crawl short distances and infest other rooms in your house. An interesting fact is that they are able to move from one apartment to another vertically and horizontally.
Are bed bugs color blind?
Bed bugs are not color blind. There is one study about how bed bugs are more attracted to certain colors than the others from researchers from the University of Florida and Union College in Lincoln, Nebraska. The tests consisted of placing bed bugs on small areas with colors.
A variety of tests were conducted, including the tests using bed bugs in different life stages, of different sexes, individual bugs versus groups of bugs, and fed bugs versus hungry bugs.
The results showed that bed bugs preferred red and black colors while avoiding yellow and green.
Also, these tests showed that the colors bed bugs chose varied based on the age and if the bug was in a group or alone. Bed bugs also choose different colors when they are hungry and fed. The interesting thing is that the male and female bed bugs also choose different colors.
Do bed bugs use vision to find blood sources?
The scientists suggest that in order to find blood sources, bed bugs use not only their vision but also other senses, such as smell and reception of chemicals. The vision of bed bugs is still the topic for research, and it’s not completely discovered. So from that, we may assume that bed bugs do not solely rely on their vision during the search for food.
How bed bugs decide which places to inhabit
Research has shown that bed bugs demonstrate a great preference for warm surfaces such as wood, plaster, paper, cardboard. They prefer temperatures within the human comfort zone, which is understandable.
If the surface is cold, like for example, metals, glass, tile, stone, or concrete, then it will be less preferable for bed bugs. However, this does not mean that the bugs will never live on these materials.
Bed bugs don’t live on their hosts. They visit the exterior of the human body only to get the food, but after feeding, they return to the places where they hide. Bed bugs are parasites of humans.
In the cases when humans are not around the area with bed bugs, they may feed on other warm-blooded hosts such as pets, birds, and cats. However, this is not very usual, as these bugs are adept at staying very close to human hosts.
Bed bugs are easily distributed around the house. They can even travel from one apartment to another. If we move one object from the area that is infested by bed bugs to another, there’s a high chance that they will live in another area and infect it as well. These annoying bugs can get into books, clothing, furniture, etc.
Even though their vision is not very good, they are still able to find many places to hide and live for a long time. That’s why you must be careful about the things you take to another room or apartment.
Bed bugs have the ability to live for a long period of time without getting any food. That’s why it’s hard to kill them solely by starving the population to death. Chemical cleaners should be used in order to get rid of the bugs properly.
Or another great way is steam cleaning, as these bugs don’t like the heat. The natural bed bug mortality is very variable and can last from three-four months to half a year. The bed bugs don’t like cold temperatures but can endure cold temperatures if needed. So even if you choose to freeze the infected area, it will be ineffective to get rid of the population.
While bed bugs do enjoy the warmth, they have heat and hot conditions. They start feeling very uncomfortable in the same temperature zones the humans do. Their slight build makes them prone to dehydration.
Especially during the development stages, the newly hatched nymph is very susceptible to extreme heat and dehydration. And it’s important to note that heat can be a more effective and reliable way to get rid of bed bugs than freezing.
Sources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4351988
https://pubmed.ncbi.nlm.nih.gov/27113099/
https://pubmed.ncbi.nlm.nih.gov/27670265/
