As mosquito season reaches its peak, many people turn to familiar home remedies in an attempt to avoid becoming the insects’ next meal.
Some eat garlic or take vitamin B supplements, while others avoid bananas, light citronella candles or rely on a variety of supposed natural deterrents. However, scientists say many of these widely repeated claims are not supported by strong evidence.
Nusha Keyghobadi, a biology professor at Western University who specialises in mosquito research, says the insects are guided by a combination of heat, carbon dioxide and body odour when searching for a host.
Only female mosquitoes bite humans. For certain species, a blood meal provides the nutrients required for their eggs to develop.
“People are a very good source of food for female mosquitoes,” Keyghobadi explained. “They need the nutrients in blood to support egg production.”
Mosquitoes can detect carbon dioxide released every time a person exhales. This helps them locate warm-blooded animals from a distance, while body heat provides an additional signal as they move closer.
Human scent also plays a major role.
The chemicals produced by the body create an individual odour profile, influenced by genetics, physiology and possibly recent diet. These differences may explain why one person can be repeatedly bitten while someone sitting nearby appears largely untouched.
Scientists have examined whether particular foods make people more attractive to mosquitoes, but the evidence remains mixed.
One study suggested that eating bananas increased mosquito attraction in some participants. However, the effect was relatively weak and varied considerably between individuals. Some people attracted more mosquitoes after eating bananas, while others attracted fewer or experienced no change at all.
As a result, avoiding bananas is unlikely to provide reliable protection.
Garlic has also been promoted as a natural mosquito repellent, but studies have not found evidence that eating it significantly reduces bites.
Similar claims have been made about vitamin B supplements, although researchers have found little convincing proof that they make people less attractive to mosquitoes.
Beer may be one notable exception. Several studies have indicated that people can become more attractive to biting mosquitoes after consuming it, although scientists have not yet fully established why.
When it comes to preventing bites, Keyghobadi says physical barriers remain the most dependable form of protection.
Screened porches, mosquito nets and enclosed mesh shelters can prevent insects from reaching people altogether. Wearing long sleeves and trousers can also reduce exposed skin.
Heat-activated devices that release synthetic mosquito repellent into the surrounding air may also be effective in small outdoor areas.
Citronella candles, however, are unlikely to offer strong protection. Although their scent may have a limited local effect, there is little scientific evidence that they significantly reduce mosquito bites in open spaces.
Personal insect repellent remains one of the most practical options, particularly when spending extended periods outdoors.
Keyghobadi said she regularly uses repellent during fieldwork to prevent bites.
Despite their nuisance value and their role in spreading disease in some parts of the world, mosquitoes also perform an important ecological function.
Many mosquito species do not bite humans at all. During their early life stages, mosquitoes live in water, where they feed on microorganisms and decomposing plant material.
Their larvae and pupae are eaten by fish and other aquatic creatures, while adult mosquitoes provide food for predators including dragonflies.
Although few people welcome their arrival during the warmer months, mosquitoes remain an important part of both aquatic and terrestrial food chains.
The most effective way to reduce bites, experts say, is therefore not to rely on dietary myths, but to use proven repellents, cover exposed skin and create a physical barrier between people and the insects.
