What Attracts Insects to Humans

Person applying bug repellent on the beach

Written by: Sulayman Mehboob, B.Sc., M.Sc. - Microbiologist


The human skin emits several odours, we also emit carbon dioxide gas and heat. Insects like warm, tropical area weather with high humidity. They also love humans who have naturally warmer body temperatures. Also mosquitoes love black and darker colors - because it traps in the heat which makes you more attractive to biting insects. Generally, the insects are attracted by the size of the prey, emission of carbon dioxide gas, body odor, blood type, body heat etc.

What Attracts Insects to Humans

These blood-sucking insects existed prior to humans. From their beginning days, insects have annoyed humans with their stings and bites and transmitted parasites. Humans have been in constant battle with these annoying insects from the beginning of time. Recently, this battle has intensified because of the increasing intolerance of insects due to the discomfort they cause. As well as our understanding of their role in the transmission of disease and the demand for having high agricultural productivity. Despite great advances in our knowledge of insects and the improvements in defending ourselves against insects, there is still no evidence of a winner in this age-old battle.

Insects can feed on human blood as a primary source of food. Insects, like mosquitoes, only female species, feed on blood from the human body in need of albumin protein which helps mosquitoes lay eggs.

There Are Several Factors That Draw Insects To Humans

1. Heat

Insects are attracted to warm, tropical and humid weather. Like humans, they have a warmer body temperature. If mosquitoes frequently feast on you, then be sure to avoid wearing black or dark colors because it traps the heat and can make you more attractive to biting insects.1

Palm Trees and Buildings in a tropical location

2. Size

Generally, mosquitoes are attracted to larger people, which may be because they have more blood content. Bodies that are larger in size and weight are also easier for mosquitoes to spot. For instance, a 250 pound athlete may be more likely to attract mosquitoes than a 20 pound child.2,3

3. Volatiles In Human Breath

One of the main chemicals which is released constantly by humans is carbon dioxide (CO2). Expired human breath consists of approximately 4.5% CO2 which is approximately 100-times higher than the 2 concentrations of CO2 in the atmospheric levels.4

4. Odour

Like other mammals, humans may have individual differences in odors and these odors may convey information on individual identity, sex, age, and motivational state.5

There are certain areas of the human body which possess a unique odor, produced due to microbial growth. For instance, the scalp of the human is a lipid-rich area because of its high density of sebaceous glands.6

Pityrosporumovale and Propionibacterium acnes are the species of bacteria that are thought to produce scalp odor. The former species transform long-chain fatty acids into more volatile chemicals, while the latter species hydrolyzes triglycerides into their individual fatty-acids.6

Another source of strong body odor are human feet. Such an odor is commonly referred as “ cheesy” and could be related to hyperhidrosis of the feet.7

5. Sweat

The hotter and sweatier a person is, the more likely insects will feast on them. The reason is that, in addition to heat, sweaty bodies produce more carbon dioxide.

6. Pregnancy

During pregnancy, women have high blood volume. Mosquitoes can sense that blood.8 Some chemicals used in the host location are produced by bacteria residing on the skin.9 Researchers performed a study and found that significantly a greater number of mosquitoes flew toward study participants who had consumed a liter of beer than participants who had consumed a liter of water.10

However, the reason for this increase remains unclear. Neither exhalation of CO2 or the skin temperature showed any correlation between consumption of mosquito landings.

The findings suggest that precaution should be taken against mosquitoes when drinking alcohol. Mosquitoes use their eyes to target the victims. Research has shown that wearing dark colors (green, black, and red) makes you easier to spot.11

Pregnant women outdoors

7. Scented Body Products

Achieving the perfect hairdo with hair spray or spritzing on your favorite fragrance is a quick and easy way to attract mosquitoes, as products having strong floral scents like lactic acids or the lpha hydroxy acids attract mosquitoes and other insects.

8. Wearing Certain Colors

In order to find nectar, bees perceive colors differently than humans, making them more attracted to certain types of shades than other colors. Studies show bees are attracted to purple, violet and blue colors, like ultraviolet lights, undetectable to human eyes.12

9. Blood Type

Studies have shown that certain blood types can be more attractive to mosquitoes and other blood-sucking insects. Observing blood types A, B, AB, and O, type O was shown to attract mosquitoes at a higher rate, with type A preferred second.

Mosquito on skin

10. Body Chemicals

The ammonia and lactic acid found in sweat work in a similar way to floral scents. Though this body odor may smell revolting to humans, to insects such as mosquitoes, you smell more like dinner. Biting insects such as bugs, flies, fly mites, mosquitoes and ticks locate and bite their host blood targets by the chemical signals they release. Such cues are called Volatile organic compounds (VOC) which are produced by their skin microbes after they metabolize human skin gland secretions so that an individual's VOC profile is largely the by-product of their skin flora. Thus, biting preference is the outcome of how each biting insect's odorant receptors detect the VOCs unique to the individual it bites.13


Different types of insects are attracted to humans with the help of several factors, including dark clothing, blood type, CO2 emission, sweat, scented body products, carbon dioxide, pregnancy, skin bacteria, body chemicals, and beer consumption have found the reasons to attract insects.

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About The Author:

Sulayman Mehboob, B.Sc., M.Sc. - Microbiologist

Sulayman has done research on various science projects and has been published in well reputed journals. Currently, he is doing research on animals and insects on various topics and some of his research projects have been completed and under review in the top journals. He loves researching plants and animals, and his aim is to continue deep study in this field.

References & Citations
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  2. Port GR, Boreham PFL, Bryan JH. The relationship of host size to feeding by mosquitoes of the Anopheles gambiae Giles complex (Diptera: Culicidae). Bull Entomol Res. 1980;70: 133–144. 
  3. Logan JG, Cook JI, Stanczyk NM, Weeks EN, Welham SJ, Mordue (Luntz) AJ. To bite or not to bite! A questionnaire-based survey assessing why some people are bitten more than others by midges. BMC public health. 2010;10: 275. pmid:20500852 
  4. GILLIES, M. T. 1980. The role of carbon dioxide in hostfinding by mosquitoes (Diptera: Culicidae): A review. Bulletin of Entomological Research, 70: 525-532.  
  5. HALPIN, Z. T. 1986. Individual odors among mammals: Origins and functions. Advances in the Study of Behavior, 16: 39-70. 
  6. SASTRY, S. D., K. T. BUCK, J. JANÁK, M. DRESSLER AND G. PRETI. 1980. Volatiles emitted by humans. pp. 1085-1129. In: Waller, G. R. and Dermer, O. C. (eds.). Biochemical Applications of Mass Spectrometry. John Wiley & Sons, New York. 
  7. TACHIBANA, D. K. 1976. Microbiology of the foot. Annual Review of Microbiology, 30: 351-375. 
  8. Ansell J, Hamilton KA, Pinder M, Walraven GEL, Lindsay SW. Short-range attractiveness of pregnant women to Anopheles gambiae mosquitoes. Trans R Soc Trop Med Hyg. 2002;96: 113–116. pmid:12055794 
  9. Verhulst NO, Qiu YT, Beijleveld H, Maliepaard C, Knights D, Schulz S, et al. Composition of human skin microbiota affects attractiveness to malaria mosquitoes. PLoS One. 2011;6: e28991 pmid:22216154 
  10. Hawkes FM, Hopkins RJ. The mosquito: an introduction. In: Hall M, Tamïr D, eds. Mosquitopia: The Place of Pests in a Healthy World. New York, NY: Routledge; 2021:16-31. doi:10.4324/9781003056034-3 
  11. Pollard EJM, Russell TL, Burkot TR. Maximising mosquito collections from barrier screens: the impacts of physical design and operation parameters. Parasit Vectors. 2019;12(1):31. doi:10.1186/s13071-019-3291-4
  12. Sharla, Riddle.“How Bees See And What it Matters.” The magazine of American beekeeping, May 20, 2016 
  13. Kamala, Trrumaila  “Why Do Mosquitoes Bite Me? Science Explains Why Bugs Are Attracted To Certain People” Medical Daily, August 24, 2016.

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