Who is sucking your blood?

The weather is getting hotter, and it's mosquito-infested season again. It scares you to death when you say it. There are tens of thousands of mosquitoes.

You must have been bitten by this kind of mosquito. Which one is it? I'll talk about it later. Picture: James Gathany, CDC / wiki commons

The life of a mosquito

Mosquito larvae, called wigglers, live in narrow still waters. Bottles and cans of stagnant water, old tires, gutters and sewers are all ideal breeding places for mosquitoes, so mosquitoes can thrive in cities where other animals cannot live.

A common mosquito breeding ground in the city. Picture: medscape.com

Mosquito larvae are typical filter feeders, living on special mouthparts to filter microbes in the water. The larvae get oxygen from the air through the breathing tube at the tail. Mosquito pupae also swim actively, which is special in insects. Pupae, like larvae, cannot get oxygen from the water, but must get it from the surface through a breathing tube, which breaks the surface by opening hydrophobic hairs, so as long as a layer of oil is poured on the surface, they will be wiped out.

The pupae of Culex pipiens pipiens, notice that the relationship between the top and bottom of the photo is upside down. Picture: Arkive

After the adults break their pupae, they can have sex after a short rest on the surface of the water. Only female mosquitoes suck blood, they need at least one meal of blood to open the yolk synthesis pathway, and the nutrients needed by offspring should be obtained from the blood. Males do not suck blood, and their mouthparts and antennae are fluffy and gaudy, which makes it easy to tell the difference between males and females.

Newly feathered male Culex pipiens mosquitoes whose feathered antennae are not yet dry. Picture: Roger Eritja / Arkive

Not all mosquitoes suck blood.

However, blood-sucking mosquitoes are limited to most members of the family Culicidae. There are many close relatives of other mosquitoes, especially Chironomus and large mosquitoes, which are often called mosquitoes, but they do not suck blood.

The habitat posture of common mosquitoes and their close relatives. From left to right: Culex pipiens, Aedes albopictus, Anopheles anthropophagus, Chironomus, big mosquito. Drawing: worms singing in the mountains

In fact, mosquitoes, Chironomus and large mosquitoes are not difficult to distinguish. Not only are they different in appearance, but they also have their own unique posture: mosquitoes have long pointed mouthparts and raise their hind legs when resting; chironomid mosquitoes have furry antennae and often rest their forefeet; while large mosquitoes have very long legs and land on six feet. It is worth mentioning that big mosquitoes are not necessarily very big, there are many large mosquitoes about the size of mosquitoes, but their slender legs and stilts are still conspicuous.

Who are the ones who suck your blood?

Let's learn more about the blood-sucking Culex mosquitoes, Aedes mosquitoes and Anopheles mosquitoes to see who is usually sucking your blood!

Culex pipiens pipiens

Culex pipiens quinquefasciatus (Culex pipiens) is a common mosquito around us. Due to the increasing development of human means of transportation, Culex pipiens pipiens has followed human footsteps all over the world.

A female adult of Culex pipiens pipiens that has just emerged from the mud. Picture: Arkive

Culex pipiens quinquefasciatus lays its eggs in still water rich in microbes and organic matter. The eggs stick together and float on the water like a raft, which is characteristic of Culex pipiens. The sight of hatched larvae bouncing and swimming in the water like rubber bands should be familiar to many people.

Click on the eggs and larvae of Culex pipiens quinquefasciatus. Picture: Arkive

As the name suggests, Culex pipiens pipiens can emit sharp tones-and so do other mosquitoes. This annoying voice is not only a simple flapping of wings, but also a love song sung by mosquitoes; they sing love songs by adjusting the sound frequency to find a suitable mate, which is similar to that of human folk songs.

Female Culex pipiens mosquitoes that suck blood. Picture: Roger Eritja / Arkive

Aedes albopictus

Aedes albopictus has a typical mosquito image: its jet-black body is dotted with eye-catching white patterns and its long legs are covered with white rings. Unlike most dark and cowardly mosquitoes, Aedes albopictus likes to move during the day, even in the hot noon; they have a strong desire to attack and are not afraid to chase and bite passing humans in broad daylight. Aedes albopictus' eye-catching coat and bold behavior have earned them common names such as flower mosquitoes and poisonous mosquitoes in the folk, while they are called Asian tiger mosquito-- Asian tiger mosquitoes in the West.

Aedes albopictus. Picture: James Gathany, CDC / wiki commons

Mosquitoes tend to like hot and humid tropical climates, but Aedes albopictus is a little different even in terms of environmental preferences: they are well adapted to temperate climates with four distinct seasons and are even more competitive in cool areas. Originally distributed in East Asia, Aedes albopictus is a common blood-sucking insect in eastern China, Japan and Southeast Asia. Now they have followed humans across the ocean and opened up new colonies in the Americas, Europe and Africa. When students who go to the United States are bitten by these mosquitoes that they are familiar with since childhood, will they also feel the affection from their hometown?

Anopheles sinensis

Anopheles sinensis (Anopheles sinensis) is another biting leprechaun around us. Anopheles sinensis is mainly distributed in China, Japan, South Korea, India, Southeast Asia and other regions, and is the vector of malaria and other diseases. There are more than 400 species of Anopheles, many of which can transmit the deadly malaria parasite.

It is not easy to identify Anopheles within the genus, but the difference between Anopheles and other mosquitoes is obvious: the jaws of Anopheles mosquitoes are very long, almost as long as mouthparts, so their needles look much thicker than other mosquitoes. The wings of Anopheles mosquitoes are spotted and look gray; when perched, the body is in a straight line from the mouthparts to the abdomen.

Anopheles sinensis. Picture: bo-protscience.fr

Their larvae are also very special. The wigglers of other mosquitoes generally sink under the water at a vertical or oblique angle, with only breathing tubes connected to the water, while Anopheles mosquitoes lie lazily against the water.

The wriggle of Anopheles sinensis. Picture: weblio.jp

Who is the most attractive mosquito?

Why are mosquito bites so itchy? It starts with the mechanism by which mosquitoes suck blood. The mouthparts of mosquitoes are highly deformed from the basic chewing mouthparts of insects. The upper lip, upper jaw, lower jaw and other parts have evolved into slender strips that drill down into the skin like a probe and a scalpel; the lower lip, like a scabbard, protects the rest of the mouthparts from piercing the skin.

When pierced into the blood vessels, mosquitoes are first injected with anesthetic and anticoagulant saliva; mosquito-borne pathogens also use this step to invade the body. The saliva injected by mosquitoes is the main culprit that makes us feel itchy, red and swollen: when the anesthetic effect of saliva disappears, the immune response caused by allergens such as proteins in saliva begins to make us uncomfortable. As each person's physique varies, so does the sensitivity to mosquito saliva.

There is a common saying that specific blood types are more attractive to mosquitoes, but there is actually not enough research evidence to support this claim. Mosquitoes rely mainly on carbon dioxide, calories and some volatile body surface compounds to find their hosts. The carbon dioxide produced by animal breathing is a common signal for blood-sucking insects to search for their host; mosquitoes can also feel the heat of warm-blooded animals, but unlike animals such as rattlesnakes that can "see" infrared thermal radiation, mosquitoes mainly sense thermal convection caused by breathing. Many volatile compounds from the human surface (a considerable number of them from the skin flora) are also one of the chemical signals for mosquitoes to target; some people are particularly popular with mosquitoes because of the wide differences in body surface odor composition among different individuals, while others are less popular.

How to get rid of annoying mosquitoes?

To get rid of these biting goblins, it is not enough to rely on the strength of one person alone; only by improving the sanitary facilities and habits of the whole society can the number of mosquitoes be effectively reduced. Monitoring the number of populations, clearing habitats, large-scale pesticide application, male sterility techniques and other commonly used means of mosquito prevention and control can not be done on their own, but need the joint efforts of professional institutions and the whole society.

Mating male and female Aedes albopictus. Picture: James Gathany, CDC

So what can we do in the face of the mosquitoes that come with the summer?

First of all, we should develop good hygiene habits, do not litter everywhere, and actively clean the courtyard and community sanitation. If you have mosquito-breeding fish ponds, lotus tanks, etc., you can put Bt insecticides or insect growth regulators that are safe for both humans and pets.

Screen windows, mosquito nets, mosquito incense and mosquito repellent sprays containing effective ingredients such as DEET are all economical and effective anti-mosquito measures. In order to cater to the psychology of consumers, the market has also launched mosquito repellent bracelets, mosquito repellent grass and other novel goods, but these are not useful.

This article is for the 2015 species Calendar, from the author of the species Calendar @ Shenshan Bug Yin.

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Aedes albopictus of mosquito family