Understand Mosquitoes (Life Cycle, Behavior, and Biology)

Mosquitoes are one of the most adaptable insects on Earth and can be found almost anywhere else. They have been discovered in mines almost a mile below the surface and even on mountain peaks at 14,000 feet. Though not all mosquitoes can bring problems for people, there are certain species that could profoundly cause diseases.

Understanding the life cycle of mosquitoes will help you prevent mosquitoes around your home and help you choose the right pesticides.

Life Cycle

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The mosquito life cycle has four stages. It begins with the laying of eggs, emerging of larvae, reaching the pupal stage, and turning into an adult mosquito.

Breeding

Mosquito breeding usually starts when the weather is warming up as these insects prefer warmer and more humid climates. Mosquitoes can survive in temperatures between 50°F and 95°F (10°C and 35°C).

The mosquito has more than 3,500 species. All these species lay their eggs in water. However, the type of water where species lay depends on the preferences of the species.

A mosquito can breed to any form of water in any form even those water in tin cans, barrels, horse troughs, ornamental ponds, swimming pools, puddles, creeks, ditches, catch basins, or marshy areas. They prefer water that is sheltered from the wind.

Eggs

After obtaining a blood meal, a female mosquito lay her eggs in the water. Before laying her eggs, the female mosquito first tests the water and takes a drink to make sure it is suitable for her larvae. Habitats with acidic water are more favorable. When laying her eggs, a mosquito pushes the eggs out through her oviduct.

Some female mosquitoes lay eggs directly on the water, near the water, plant bases, and even outside of the water. Eggs can either be individual or attached in a group called rafts. A single raft of 200 to 300 eggs is about 1/4 inch long. Those eggs that are not yet exposed to the water can survive many years before hatching. Once the egg is exposed to the water, it will hatch within 24 to 72 hours.

Larval stage

After the eggs are laid, mosquito larvae emerge within 24 to 48 hours. These larvae are commonly called “wigglers” and can live in water for 4 to 14 days. The larva looks like little wriggling worms swimming around the water.

From time to time, larvae must come to the water surface to obtain oxygen through the breathing tube called a siphon. Species of Coquillettidia and Mansonia uniquely draw their oxygen from plants. The growing larvae nourish themselves by filtering anything small enough to be eaten toward their mouths. They can feed on algae, plankton, fungi, bacteria, and other microorganisms.

Toxorhynchites and some Psorophora are some of the largest species of mosquitoes that are cannibalistic and can feed on the larvae of other mosquitoes.

During growth, a larva can shed its skin up to four times. This stage is known as “instars”. When it reaches a length of almost 1/2 inch, it can become a pupa. The larvae development takes about 7 to 10 days to become a pupa.

Pupal stage

Mosquito pupae are comma-shaped and are commonly called “tumblers”. The head and thorax are fused and enlarged and the segmented abdomen attached to this region hangs down below it. Species have different feature in pupa stage such as the placement of small hairs in the abdomen.

Depending on the temperature and species, pupae can live in water for 1 to 4 days. They float at the surface and take oxygen through two breathing tubes called “trumpets”. When disturbed, the pupae employ a rolling or tumbling action going to deeper water.

The pupa of mosquitoes more active compared to the other pupae of other insects. This is the stage of a mosquito when it does not feed, instead, taking in oxygen to survive.

The pupal stage lasts about 4 days and it is when the mosquito develops into a metamorphosis. It comes with a pupal case and develops the body organ of an adult mosquito. When a pupal case splits up, the adult mosquito emerges and rests at the water surface.

Adult mosquitoes

Adult mosquito is the final stage of the mosquito life cycle. Usually, the male mosquito lingers near the breeding site and waits for the female mosquitoes. Then, mating occurs quickly. After mating, the male mosquito typically dies.

For the female mosquito to develop her eggs, she needs a blood meal. After the blood meal, the female mosquito will oviposit or lay her eggs. The blood meals are the source of protein to mature her eggs. Some species only lay eggs once while several species may lay eggs many times over the course of their lives.

An average female mosquito can fly up to 10 miles but there are certain species that can travel up to 40 miles. Male mosquitoes can survive for about a week or two. On the other hand, the female mosquito has a longer lifespan and can live for several months.

The male mosquito does not feed on a blood meal, instead, feeds on the plant nectar. There are female mosquitoes that can also feed on plant nectar, however, they also need blood in order to reproduce. The species of Toxorhynchites are restricted to plant nectar diet and never obtain a blood meal. The mosquito blood-feeding is influenced by a combination of carbon dioxide, temperature, moisture, smell, color, and movement.

Morphology of different stages

Do they have teeth?

Mosquitoes do not have teeth, though they bite humans and animals. But, it is not the same way as the bite of mammals with teeth.

When a female mosquito finds her target, she has to find a suitable blood vessel to puncture. They will prefer a nice warm spot to bite. The bite of a mosquito is like a venipuncture which is the collection of blood from a vein.

In at least 3,500 species, there are only a fraction of mosquitoes that bite humans. Others take blood from animals such as mammals, birds, reptiles, and even some fish.

Why do mosquitoes buzzing?

Mosquito buzzes to help them find suitable mates. Males would identify the buzz as female mosquitoes because they are larger and they flap the wings slower. This distinct pitch of the female buzz helps them recognize possible mates.

In a study conducted by Louis M. Roth, males would ignore resting females and would be attracted to mate with females who are flying around and buzzing.

Can mosquitoes see at night?

Mosquitoes can not see in the dark. However, mosquitoes are attracted to the carbon dioxide exhaled by humans and other animals as far as 30 to 160 feet away. They even have receptors and vision to identify targets like body heat, perspiration, and skin odor.

Mosquitoes are nocturnal and bite more during at night because humans and animals who are resting release more carbon dioxide. During the daytime, mosquitoes prefer to rest in cool places such as those near water.

Why do mosquitoes fly up and down?

Mosquitoes flying behavior is different from other similar-sized insects like butterflies and bees. Mosquitoes combine short wing flaps with a swiveling motion. This rapid move creates pockets of air to launch them into flight and keep them afloat.

The mosquitoes flying behavior is associated with creating a buzz to find a suitable mate. A mosquito flies up and down to whine at a different frequency and to produce a sexually-sounding trait.

What do mosquitoes need to survive?

The mosquitoes’ needs to survive depends on gender, life cycle stages, and species. Generally, males feed on the plant nectar while females would need both plant nectar and a blood meal. The blood meal for females is necessary to nourish the eggs.

To survive the different stages in the life cycle, mosquitoes have varying needs. During the larval stage, they need to feed on anything such as algae, plankton, fungi, and bacteria. They need oxygen as well and uses the breathing tube to breathe at the water surface. During the pupa stage, they would need more air. At the adult stage, mosquitoes need to take in plant nectar and blood meal. But in all life stages, mosquitoes have one thing in common- they need water.

Are larval survive if the water is drying?

The mosquito in its larval stage needs primarily water. This is where they get food such as plankton, algae, and bacteria. Without access to the water, the larva is likely to dry out and die eventually.

This is the reason why removing stagnant water where mosquitoes would likely live is the best way to get rid of mosquitoes.

Do they die in freezing water?

During colder months, mosquitoes go into hibernation. They will find a hole to hide into and wait until warm weather comes. If some of them choose to lay an egg, the eggs will typically survive but the laying mosquito will then pass away shortly after. The eggs will be hatch when the water is warm enough.

In freezing water, mosquitoes will be killed virtually in a hard or killing frost which is two consecutive hours at a temperature below 28°F (-2°C).

What is the maximum temperature they can handle?

During cold weather, mosquitoes will die at temperatures below 28°F (-2°C). They are cold-blooded insects and become lethargic in cold.

Mosquitoes prefer hot weather and is essential for survival. They are more active in temperatures above 80°F (27°C). The heat can even lead to rising in their population. But, extreme heat with no humidity can dry them out and eventually kill them.

An approximate 104°F (40°C) is the maximum temperature that mosquitoes can handle. Mosquitoes have unique receptors that can identify the temperature of a certain thing and they will avoid touching its surface.

Feeding

The feeding behavior of mosquitoes depends on the life stage of their life cycle.

During the larval stage, they would feed on anything that can fit on their mouth such as plankton, algae, and bacteria. During the pupa stage, they wont feed on anything. They would depend on air to survive.

At the adult stage, mosquitoes would feed on plant nectar or its honeydew to get sugar. However, female mosquitoes would need a blood meal as a source of protein to nourish the eggs.

Though most common mosquitoes would feed at dawn and dusk, some species are particularly aggressive and feed both day and night.

What attracts mosquitoes?

There are many factors that could attract mosquitoes. Initially, they are attracted by carbon dioxide exhaled by humans and animals. Body heat, bacteria, sweat, blood type, pregnancy, and alcohol intake are also some of the contributing factors. It is believed that 400 chemical compounds on human skin can attract or repel mosquitoes. Mosquitoes have the ability to smell their dinner from a long distance of 50 meters.

However, different species have also different preferences. For example, the Aedes aegypti species that spread Dengue Fever are particularly attracted to sweat that contains a substantial amount of lactic acid. On the other hand, the Anopheles gambiae species that spread Malaria are attracted to smelly feet as they are associated with the smell of Limburger cheese.

How do mosquitoes bite you without you knowing?

Generally, the mosquito bites are itchy and they can swell because of the mild reaction of the body to the mosquitoes’ saliva. Then, the body will release histamine to combat the coagulant delivered by the mosquito’s saliva.

There are some people that could not easily feel the mosquito bite. The mosquito senses the right spot to pierce the skin and access the blood. The mosquito injects saliva that could numb the area and prevent clotting. This way makes the mosquito feed undisturbed. As the mosquito fly away, the body of the host will then react to the saliva that was left behind, and feel itchy and swelling on the skin.

This reaction differs on the level of sensitivity of the person being bitten. Some even experience minor allergic reactions while few may suffer allergic reactions.

Where do they find blood?

Mosquitoes have many methods to locate a potential host. Carbon dioxide, body heat, perspiration, and skin odor are being considered in finding a potential host. According to the study published in the journal Current Biology, the female mosquito has a certain olfactory receptor in its antennae to detect potential host. The receptor is attracted to human sweat and acid volatility.

Why do they need blood?

Only the female mosquitoes need blood meal, though they can also feed on plant nectar. The blood meal is a source of protein and iron to make and nourish the eggs. She will need about three milligrams of blood per bite for reproduction.

Another reason for the mosquito’s need for blood is being dehydrated. The blood meal is a source of beverage for them to quench the thirst, especially during warm weather. Mosquitoes would feel the dehydration only a few hours after the feeding.

Do they die without a meal?

Adult mosquitoes can go as long as six months without eating or drinking during the hibernation stage in cold weather. During warm weather, the adult mosquitoes need a regular meal such as plant nectar. Without a meal within four days, mosquitoes would likely die.

What happens to a mosquito after it bites you?

If a mosquito bites a human and avoids being squashed, it can live for as long as three weeks. The female mosquito may lay up to five clutches of more than a hundred eggs each.

The blood meal is necessary to produce eggs but it poses a huge metabolic process challenge. If the process is disrupted, the female mosquito will not complete the egg production cycle.

According to the study conducted by a team of biochemists at the University of Arizona, mosquitoes would likely die within 48 hours after a blood meal if the protein components are experimentally disrupted.

Are they useful?

Mosquitoes may be associated with different life-threatening diseases such as Zika Virus, West Nile Virus, Dengue Fever, Malaria, and so on, but this insect has also a purpose in our ecosystem.

The larvae can also serve as the source of food for fish and other wildlife. The larvae themselves eat microscopic organic matter in the water that could help recycle it. If the mosquito would go extinct, some fishes would be affected and may also extinct. Thus, the food chain would be disrupted.

The adult mosquitoes also serve as the source of food for some insect-eating animals such as birds, bats, dragonflies, spiders, and frogs.

As they consume plant nectar, the adult mosquito may also help in pollination.

Do they have a role in pollination?

Generally, mosquitoes feed on the plant nectar. They can transfer pollen from flower to flower which is necessary for plant fertilization. This is turn would help the plant to form seeds and reproduce.

There are some plant species such as the blunt-leaf orchids that are totally dependent on mosquitoes for pollination.

What would happen if mosquitoes went extinct?

The mosquito may have a negative impact on our health but this insect has also played an important role in the ecosystem. Just like any other creature, the extinction of this insect may disrupt the food chain and would impact everything from pollination to biomass transfer to food webs.

Fishes that may depend on the larvae as the sole source of food may also go into extinction. Fishes may also need to change the feeding system if they also feed on the larvae.

Moreover, plants that depend on the 3,500 mosquito species in their pollination may also be affected. Some of these plants are orchid species and are dependent on mosquitoes. In the Arctic, mosquitoes are important for pollination during the short growing season.

Mosquito Habitat

Mosquito habitat can be found almost every place with standing water. These places range from ponds, swamps, marshes, plants, trees, puddles, and artificial water containers such as abandoned tires, flower vases, buckets, and more. These forms of water are essential in breeding to becoming adult mosquitoes and as a source of food.

One of the unique and interesting habitats of mosquito larvae is found in the carnivorous pitcher plant or the Sarracenia purpurea. Both the plant and larvae benefit from the water and decomposing insects. Also, several mosquito species put their eggs in the water collected between the leaves of plants in the Brazilian Atlantic forest.

Climate

Mosquito prefers warm weather in breeding and living. They can survive extreme high temperature as they have the ability to identify hot surfaces.

During the colder climate, mosquitoes also find some hole to hibernate. If they choose to lay eggs in freezing water, the eggs will survive and will hatch when the water is warm enough.

Laying eggs

Generally, a female mosquito will lay 50 to 500 eggs at a first time. These eggs are sticking together to form a raft which measures about 1/4 inch long and 1/8 inch wide. The subsequent eggs are typically fewer but she can lay up to 10 times throughout her life. Though eggs can survive in dry areas, eggs will hatch when submerged in water.

Generally, it takes 10 to 14 days to develop the eggs in standing water. Perhaps, this is the reason why it is recommended to dump any standing water at least once a week to get rid of mosquitoes.

Mosquitoes lay eggs in any container of water or in any form but salty water. She will first test the water to ensure that it is favorable for her eggs. She tastes the water by dipping in its legs and mouthparts.

Activity

Mosquitoes are very much active when the weather is warm and humid. For tropical regions, mosquitoes are active for the whole year because of the favorable weather. In cold regions, mosquitoes goes into hibernation.

Means of dispersal

Mosquitoes are dispersed worldwide through various methods such as sea transportation, personal vehicles, delivery trucks, trains, and aircraft. Primarily, they are being transported through containers inhabited by mosquito eggs, larvae, and pupae such as used tires. Mosquitoes can survive in stagnant water in any container. This means of dispersal make the mosquitoes reach large distances and become indigenous to a certain place.

Vector of disease

Mosquitoes are associated with many life-threatening diseases. By nature, a mosquito doesn’t cause any disease except for the itchy mosquito bite. However, this insect is considered a vector of various life-threatening mosquito-borne diseases such as Zika virus, West Nile virus, Chikungunya virus, Dengue, and Malaria. They can carry diseases and transmit them to humans. This ability is known as the vectorial capacity.

The vectorial capacity depends on many factors such as the geographic range, the preference of biting humans or animals, the timing of reproduction, and the resistance to insecticides. The Anopheles gambiae and Aedes aegypti are some of the most effective disease vector species that are constantly evolving. Vector-borne diseases occupy more than 17% of all infectious diseases that leads to 700,000 deaths annually.

One of these diseases is Malaria that is transmitted by the Anopheline mosquitoes. It leads to an average of 400,000 deaths annually and affected approximately 219 million cases globally and most of these are children under the age of 5 years.

Another vector-borne disease is Dengue which became the most prevalent viral infection that is transmitted by Aedes mosquitoes. In over 129 countries, it is estimated that more than 3.9 billion people are at risk of Dengue fever and caused around 40,000 deaths every year.

In transmitting diseases, mosquitoes must bite a sick human first. Then, the mosquito becomes infected with the pathogen which will become infectious in usually around ten days. Then, the infected mosquito will bite another human and transmit through the blood the pathogen.

The mosquito that infects themselves through blood meal from a bird or a horse may also transmit the disease to a human. This is usually the case of West Nile fever in which mosquitoes become the bridge vectors. Culex is one of the mosquito species that are bridge vectors.

Is there some seasonality of the outbreak?

According to the World Health Organization, Dengue Fever outbreaks likely increase during rainy seasons. Dengue is one of the fastest-spreading diseases brought about by mosquitoes and became a major public health concern.

In a study conducted in the United Kingdom, the seasonality of the outbreak is being associated with the environmental variables, vector, and pathogen life cycles. The pattern of mosquito seasonal abundance due to high rainfall contributed largely to increasing the population in aquatic habitats.

Mosquitoes VS Other Insects

Mosquitoes are among the winged insects in the Order Diptera such as bee fly, robber fly, horse fly, black flies, sand flies, and biting midges. This Order has more than 125,000 species that are relatively small and with soft bodies. Mosquito came also from the family Culicidae, which is considered the most prolific disease vector that can transmit a range of parasites, viruses, and flaviviruses. Among all other 3200 recognized species of the family Culicidae, the long proboscis of mosquito is distinctive and indicates a long and close association with vertebrate animals.

Size

Generally, adult mosquitoes are 0.15 to 0.4 inches long. But not all mosquitoes are similar in size because some species are less than 0.1 inches long.

The Psorophora ciliata mosquito is one of the largest species that measures about as long as the diameter of a quarter. The Australian elephant mosquito Toxorhynchites specious is also among the largest in the world, but fortunately, it is not a blood feeder.

Comparing with other insects, crane flies is one of the insects that are typically mistaken as mosquitoes. It has long legs and much larger than mosquitoes and commonly referred to as the “mosquito killers“. But, crane flies are harmless insects that do not feed on mosquitoes or even bites humans, rather, feed on plant nectar.

Other insects that look like mosquitoes are midges. They are similar in size but the key difference is that midges do not bite. Midges are considered only as a nuisance as they are found swarming in areas with mud on bottoms of lakes, ponds, spreading basins, and flood control channels.

Another insect that is mistaken as the mosquito is the fungus gnat. Mosquito and fungus gnat is similar in size and range between 1/8 to 3/8 of an inch. Just like midges, fungus gnats do not bite but only swarm especially in moist decaying vegetation.

Color

Insects have unique characteristics in their color. Some insects use flashing lights to attract the opposite sex. Many insects imitate other insect’s colors and form to avoid their predators.

Mosquitoes vary in color and appearance depending on their species. They are mostly gray with white, silver, green or iridescent blue scales in color. They have white stripes across the abdomen.

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