Mosquitoes are well known for being annoying and dangerous insects. Their bites can cause irritation and itchy welts, and some species spread diseases like malaria, yellow fever, dengue fever, Zika virus, and encephalitis. Mosquitoes use several different cues to find and target their victims including carbon dioxide, body odor, warmth, and visual cues. But do mosquitoes have color preferences when seeking hosts? Let’s take a look at the evidence.
Quick Answers
– Mosquitoes are more attracted to darker colors like black, red, and blue.
– Lighter shades like yellow, green, and white are less attractive to mosquitoes.
– Mosquitoes use vision primarily for long-range targeting. They rely more on smell up close.
– Dark clothes stand out against light backgrounds, making the wearer more visible.
– Dark colors also absorb more heat, making dark-clothed hosts warmer and more prominent.
How Mosquitoes Use Vision to Find Hosts
Mosquitoes have incredibly sensitive and discerning eyesight. Their compound eyes contain thousands of light-sensing ommatidia. This allows them to see fine details and movements from up to 40 meters away. Mosquitoes primarily use vision to detect objects that stand out from the background environment. This helps them hone in on hosts from a distance. Up close, mosquitoes rely much more heavily on chemical cues like carbon dioxide, body odors, and heat to zero in for the final approach. So while color is more important for long-range detection, smell and temperature take over once the mosquito gets within 15-20 meters of a potential victim.
Color Preferences of Mosquitoes
Research has consistently shown that mosquitoes are more strongly attracted to darker colors compared to light ones. Here are some of the key findings about mosquito attraction to different colors:
Black
– Multiple studies have found that black is one of the most attractive colors to mosquitoes. In one study, black clothing attracted about twice as many mosquitoes as any other color.
– Black may be highly attractive because it is such a strong visual cue against most backgrounds.
– Black also absorbs a lot of heat from sunlight, making black-clothed hosts stand out as warmer targets.
Red
– After black, red is likely the next most attractive color to mosquitoes. Red is highly visible against most backdrops.
– Some research suggests mosquitoes may also be drawn to the color red because of its similarity to our blood and vascular networks. However, this theory needs more research for confirmation.
Blue
– Blue is also one of the more attractive colors to mosquitoes compared to lighter shades.
– Blue contrasts strongly against many backgrounds, making hosts stand out more.
Orange, Yellow, Green
– Colors in the orange to yellow range attract fewer mosquitoes than shades like black, red, and blue. But they are still more attractive than lighter colors.
– Greens are somewhat neutral for mosquito attraction. Lime green attracted the most mosquitoes of any lighter color in one study.
Tan, Beige, Khaki
– Light browns and tans attract fewer mosquitoes compared to dark colors. But they get more attention than the lightest shades.
– These muted colors provide some camouflage against earthy backgrounds, making them less visible to mosquitoes.
White, Light Gray
– The lightest shades like white and light grays attract the fewest mosquitoes.
– White clothing reflects a lot of light, making the wearer practically invisible to mosquitoes against a bright background.
– Light colors also absorb less heat, so the wearer’s body heat does not stand out as much.
Studies on Mosquito Attraction to Color
Several controlled studies have tested mosquito attraction to different colors using human subjects wearing clothing of varying shades:
Browne and Bennett 1980
This study looked at mosquito attraction to subjects wearing white, black, red, and blue shirts outdoors. The results showed:
– Black attracted the most mosquitoes, nearly 2x more than any other color.
– Red and blue attracted similar numbers, about 2x the mosquitoes attracted to white.
– White attracted the fewest mosquitoes, about 1/4 the number attracted to black.
Yoshimura and Janra 1996
This study tested mosquito attraction to nine different colors worn by test subjects: white, khaki, green, red, black, pink, blue, purple, and yellow. The results showed:
– Black attracted the most mosquitoes, followed by red and blue.
– Khaki, green, and purple attracted an intermediate number of mosquitoes.
– Pink, yellow, and white attracted the fewest mosquitoes.
| Color | Mosquito Attraction |
|---|---|
| Black | High |
| Red | High |
| Blue | High |
| Khaki | Moderate |
| Green | Moderate |
| Purple | Moderate |
| Pink | Low |
| Yellow | Low |
| White | Low |
Anjali et al. 2003
This study evaluated mosquito attraction to subjects in black, red, blue, green, and white clothing. The findings were:
– Black and red attracted the most mosquitoes.
– Blue and green attracted an intermediate number.
– White attracted the fewest mosquitoes.
The researchers suggested that darker colors may attract more mosquitoes because they:
– Absorb more heat from sunlight.
– Contrast strongly with natural backgrounds.
– Are more similar to our vascular networks.
Do Mosquitoes See Color or Just Contrast?
Some research has suggested that mosquitoes may not see colors per se, but rather are drawn to visual contrast against the background. However, most experts believe that mosquitoes do have some degree of color vision and are attracted to certain wavelengths more than others. The specific opsin genes that allow for color vision have been identified in mosquitoes. And they have a much higher percentage of color-sensitive cone cells in their ommatidia compared to insects that only see in black-and-white. The stronger attraction to darker rather than lighter shades also indicates an ability to discriminate colors, not just contrast.
Other Factors that Influence Mosquito Attraction
While visual cues like color play an important role in mosquitoes seeking hosts from afar, other factors become more important up close where smell, temperature, and vapor plumes take over:
Carbon Dioxide
– Mosquitoes can detect CO2 from over 50 meters away. They fly upwind to reach the source.
– We exhale about 4% CO2 with each breath, signaling our presence.
Body Odor
– Mosquitoes are drawn to lactic acid, ammonia, and other components of sweat and body odor.
– Genetic factors in our odor profile also make some people much more attractive.
Warmth
– Mosquitoes use thermal radiation to zero in on warm-blooded hosts once nearby.
– Higher contrast between body and ambient heat makes a person more visible.
Moisture
– Mosquitoes gravitate toward heat and vapor plumes that signal respiration.
– Arid conditions reduce human moisture and scent gradients that attract mosquitoes.
Wind
– Mosquitoes fly upwind when tracking hosts by odor, heat, and CO2 plumes.
– More breeze disrupts their ability to follow these signals to the source.
Pregnancy
– Pregnant women produce 21% more CO2 and nearly 1 degree C more body heat, making them more attractive to mosquitoes.
Beer
– Drinking beer increases CO2 production and makes sweat and body odor more attractive to mosquitoes.
How to Avoid Mosquitoes Based on Color
Knowing that mosquitoes see dark colors more readily than light shades, here are some tips for using color to your advantage:
Wear light colors
Stick with white, khaki, light grays, and pastels when possible to become less visible to mosquitoes. Lighter fabrics should also be tightly woven to reduce heat signature.
Avoid dark clothes
Skip the black, red, blue, and dark purple if you will be outdoors at dusk when mosquitoes are most active. These colors make you stand out more.
Camouflage clothing
In areas with green foliage, wear greenish hues that blend with the landscape. In arid and beach environments, tan and sand colors will provide better camouflage.
Loose, long-sleeve shirts and pants
Covering up exposed skin reduces contact, and loose-fitting clothes mean less contact with skin. Tuck shirts into pants.
Avoid floral prints and jewelry
Solid colors work better than prints, stripes, and patterns that may attract attention. Remove or cover shiny jewelry.
Insect repellent with DEET or lemon eucalyptus oil
Topical repellents applied to exposed skin, clothes, and gear provide additional protection by masking attractive odors.
Conclusion
Research clearly shows that mosquitoes respond more strongly to darker colors, especially black, red, and blue, compared to lighter shades. However, smell, temperature, moisture, and other factors also influence mosquito attraction, especially at closer range. Wearing light-colored, loose-fitting clothing can provide some protection against mosquitoes by making you less visually conspicuous. But topical repellents, avoiding peak activity hours at dawn and dusk, and eliminating breeding grounds are also important for reducing mosquito bites.
