Why Mosquitoes Bite at Night While You Sleep

Mosquitoes love to attack at night while a person is in bed sleeping. Personally, I often get mosquito bites in clusters on my feet while I’m sleeping or out-and-about at night.

If a hungry mosquito is on a rampage in your room at night, there are several tricks you can use to protect yourself (described below).  One is to turn the artificial light on. This tricks the little bastage into thinking it is daytime. Give it a try. It works. The mosquito usually goes back into hiding and leaves me alone.

Why do mosquitoes prefer to feed at night, and what can we do to protect ourselves? Let’s take a look.

It’s safer for mosquitoes to be active at night

For a moment, put yourself in the shoes of a hungry mosquito. You know that your life is in mortal danger every time you go in for a blood meal. (How many time have you caught a mosquito mid-bite and squashed it with the palm of your hand?)

Mosquitoes do inject a mild anaesthetic into the skin just before drawing blood. Otherwise, you would likely feel the mosquito bite and kill it before it could draw blood. It’s dangerous business and the mosquito knows it.

You might think mosquitos are just dumb, robot insects. This idea is humorous and partly true. But evolution has given mosquitoes the instinct to know that biting at night, when the victim is sleeping and incapacitated, is a much safer bet.

Because, when you sleep, the almost imperceptible pinprick of a bite will go unnoticed. The victim only wakes up after the anaesthetic has worn off, when the pain and itching of the bite(s) forces its way into consciousness. But by then it is too late. The mosquito, engorged with your delicious blood, has already escaped into the yawning night.

Mosquitoes have night vision

Mosquitoes have a distinct advantage when feeding at night. They have a type of infrared night vision that makes it easy to locate us. But obviously, it is very difficult for us to see mosquitoes in the dark.

How does a female mosquito locate a potential victim? She has special sensors in her proboscis, or mouth parts, that detect carbon dioxide. When mammals breathe, carbon dioxide is emitted, and mosquitoes can key in on it from quite a distance. They use this cue to move in for closer inspection.

Once in closer range, the mosquito has other special tools at its disposal, which also don’t require the presence of light. The mosquito analyzes skin for the presence of various bacteria, proteins, and compounds in sweat, which evaporate and waft through the air around our skin.

Scientists believe mosquitoes determine who and when to bite from a complex algorithm based on  these signals. Many studies have confirmed this theory, but the complexity prevents it from currently being well understood. This is why some people are more prone to mosquito bites than others.

How many times can a mosquito bite in one night?

A mosquito doesn’t always bite just once and then go away. Especially at night. When you sleep, a mosquito knows it has an easy target. So, it often bites multiple times, until fully satiated and bloated with blood.

It often doesn’t bother moving very far for the next bite. As I mentioned, I often suffer multiple mosquito bites in a cluster on my feet while sleeping or out at night. By the time I feel the bites, I already have up to 7 or 8 of them, and the little thief has disappeared into the darkness.

There is no limit to how many times a single mosquito can bite, other than its capacity to consume blood. One mosquito can easily bite 4 or 5 times.

Pro tips for preventing mosquito bites at night

There are several things you can do to protect yourself from mosquito bites while you sleep:

1. Sleep with the light on: As mentioned above, I do this and it works. It may be more difficult to sleep with the light on, but it’s  definitely a better option than getting eaten alive by a marauding mosquito. It works with most, but not all, species of mosquitoes. The artificial light tricks the mosquito into thinking it is daytime, triggering it to go inactive.
2. Aim an electric fan on your body:  Obviously, only applicable in warm weather. The flow of air from a fan makes it difficult for a mosquito to land on you. The wind also disperses the chemical signals emanating from your skin, confusing the mosquito.
3. Cover bare skin: Mosquitoes can bite through clothes, but it much more difficult for them. If a mosquito is biting at night, cover your body with a sheet or blanket. If you get bitten on your feet like I do, put socks on. Wear pajamas.
4. Use mosquito repellant: Put mosquito spray on any exposed skin, such as hands and face. There are many effective types of mosquito repellent that are suitable for indoor home use. They can help keep mosquitoes at bay while you sleep. Look for links to various types of mosquito control at the end of this article.
5. Close windows: Might seem obvious, but mosquitoes have to get into your room somehow. Usually that is through an open window.

Conclusion

Depending on the species, mosquitoes are usually most active at night, especially around dusk. There are real survival advantages that explain why mosquitoes have evolved this tendancy.

Understanding how to combat this behavior helps you better protect yourself from mosquitoes after twilight. Hope this article helps you understand the nocturnal behavior of the mosquito, and gives you ideas on how to prevent mosquito bites while you sleep.

Photo: “Mosquito tigre” by calafellvalo is licensed under CC BY-NC-ND