Bite-free summer: How to escape mosquitoes

Sweat, blood, carbon dioxide, and even the soap you use are among the many factors that attract mosquitoes to bite you. Knowing the “enemy” is the first step to ensuring nights without bites and without compromising biodiversity.

As the summer arrives in Portugal, the days become longer and more inviting to engage in outdoor activities. But there is a persistent visitor who insists on visiting us in the evening: the mosquito. This small dipteran, belonging to the Culicidae family, not only prevents us from having quiet nights but can also pose real risks to human health.

There are more than 3,500 species of mosquitoes worldwide, causing over one million deaths annually, acting as transmitters of diseases such as malaria, dengue, yellow fever, Zika and West Nile virus. In Portugal, the tiger mosquito (Aedes albopictus) has been expanding its geographical distribution, hence the need to put more effective preventive measures in place that respect the ecological balance.

Researchers were thus impelled to know these arthropods better and find out what drives them and what leads them to choose their victims, and a certain type of person over another.

Why are some people bitten more than others?

Several scientific studies help explain why certain individuals appear to be more appealing to mosquitoes. One of the main factors is the blood type. People with type O blood are 85% more likely to be stung than those with type A or B.

Mosquitoes can detect chemical signals on the skin, such as lactic acid, and are especially attracted to carboxylic compounds present in human sweat, which have a rancid butter-like odour. The skin microbiota also plays an important role, as certain microorganisms produce irresistible odours for the little bloodsuckers.

In addition, these insects are true “chemical hunters”, are able to detect carbon dioxide from human breath up to 60 meters away, identify dark silhouettes and prefer warmer areas of the body.

Oddly enough, the use of scented soap, even with compounds such as limonene (considered a repellent), can, in some cases, increase the attraction of mosquitoes, depending on the chemical combination with each person’s skin.

Strategies to protect and respect biodiversity

While there is no universal repellent yet, there are several ways to reduce the risk of being bitten:

• Wear light, bright clothing that covers most of your body. Mosquitoes are attracted to dark colours.
• Avoid peak hours such as dawn and dusk.
• Install mosquito nets on windows and beds, especially in areas with dense vegetation or near water.
• Eliminate still water points around the house: pots, gutters, tires or forgotten containers are authentic nurseries for larvae.
• Use effective repellents, preferably with DEET (N,N-diethyl-meta-toluamide), still considered the most reliable compound, or natural alternatives such as lemon eucalyptus oil.
• Try coconut-scented soaps, which in some studies have been shown to have repellent potential.
• Grow aromatic plants like lavender, basil, rosemary, or citronella that help ward off mosquitoes naturally.

Support natural predators

Not all insects are our enemies. Dragonflies, for example, are great allies in the natural control of mosquitoes as well as some beetles. But also bats, swallows and even some types of spiders may be helpful in this. Installing nest boxes or avoiding the use of chemical pesticides can help create a favourable environment for these predators, contributing to a more balanced and sustainable biological control.

The fight against mosquitoes should be a community responsibility. From small individual actions to public prevention policies, we can all contribute. Participating in awareness campaigns, alerting to breeding hotspots in public spaces or encouraging nature-based solutions are important steps towards a safer summer free of bothersome bites.

Did you know that…

• 1. Only females bite

  Only female mosquitoes bite, as they need blood to obtain proteins and iron essential to the development of their eggs. Males feed only on nectar.

  2. The mosquito tinnitus serves a purpose

  The high-pitched sound we hear is produced by the flapping of the wings, which vibrate between 300 and 600 times per second (up to 700 Hz or more). Tinnitus is produced by such high-speed vibration and acts as a means of communication between males and females during mating.

  3. Beer makes you a more desirable target

  Studies have shown that people who drink beer attract more mosquitoes, even without obvious changes in body temperature or expired carbon dioxide. The reason is not yet well known, but changes in body odour after beer consumption may be the cause.

  4. Mosquitoes are older than dinosaurs… almost

  The most reliable mosquito fossils date to about 125 million years ago, during the Cretaceous period. However, molecular analyses indicate that this group already existed approximately 197 million years ago, in the early Jurassic.

1FSC® – Forest Stewardship Council® (Licence no. FSC® – C010852)

2PEFC – Programme for the Endorsement of Forest Certification schemes (Licence no. PEFC/13-23-001)