Mosquitoes are widespread all around the world, and there are about 2500 species of these biting insects, 150 of which are flying around the USA. Only in California there are more than 50 species. In 99% of cases people are bitted by one of only eight species from the whole variety of mosquitoes.
Each kind of mosquitoes has its own Latin name in scientific classification. Each name contains some unique characteristics that differ the species one from another. Many species have also common English names, alongside with Latin ‘identifiers’. For example, Aedes aegypti is also called ‘yellow fever mosquito’
The common peculiarity for all mosquitoes – they need to dwell near some standing water bodies to be able to reproduce. It can be any kind of water, from melted clean ice to dirty sewages, small swamps or huge lakes. By the way, some species oviposit in specific types of water bodies, and depending on the place where the larva was found, a researcher can define the species of mosquito. Adult individuals oviposit in dark damp places where water can stay after rains. This can be tree holes, some cracks, bottom lands, ponds, damp fields with irrigation system, etc. The environmental conditions required for habitation are different for each kind of mosquitoes.
It is interesting to know that only adult individuals can bite and feed on blood from people and animals. And what more, only female mosquitoes bite. They can bite any wild or domestic animals, birds, reptiles, frogs, etc. Different species are used to feed on specific kinds of animals, one can bite people but be indifferent to wild animals. Or mosquitoes living near the lakes can bite only frogs and reptiles. Male and young female individuals are herbivorous, living on juices of various grasses and tree leaves.
The necessity of animal blood intake is required for producing eggs. That is why they are bloodsucking insects. For the majority of mosquitoes, the absence of blood meal means death without ability to lay eggs that are able to grow up to larvae. Nevertheless, there are some kinds of mosquitoes that during evolution become able to do without blood.
As for the flying capabilities, mosquitoes have different habits. Some species spend the whole life cycle near their place of birth and do not migrate for long distances, while other prefer to travel far away from homes. Female individual are more inclined to migration than males. The distance of possible migrations is mostly defined by winds that occur in the territory of habitation. General radius of migrations is 1 – 2 miles around the source, but some species can fly away for up to 75 miles.
The life span of mosquitoes is conditional on various factors like the season of the year, sex, climate, etc. Males usually live for much shorter time, up to a week. Female individuals’ life lasts for a month or so, but this can differ depending on their environmental conditions.
The life cycle of mosquitoes consists of four phases. First, an Egg appears, it turns into Larva, that continuously grows up to Pupa, and finally, an Adult individual. Each phase of life differs from the others by definite characteristics.
Eggs can be laid in a few variants. Some species lie eggs on the water surface, while other one prefer damp ground that will be covered with water after rains or tides. Eggs can drift on the water surface separately by one, or can be combined in so called ‘rafts’. All these peculiarities depend on mosquito species, and of course you can find out which kind of insects it is by looking at its batch of eggs. As a rule, an egg turns into larva in two days (forty eight hours).
Larva usually lives in the water that is why it is necessary for mosquitoes to live near water bodies. Larva comes upward, on the water surface for breathing. During the process of growth mosquito larva shed skin a few times. They breathe by either siphon tunes or simply by their skin, lying on a surface of water. The main food is various plankton microorganisms from the water. After shedding the skin four times, larvae turn into a pupa.
While being a pupa, mosquito individual doesn’t eat anything, it uses the nutrients collecting during the previous phase of growth. This is the phase of rest, lasting about two days. Then the pupal skin breaks, and mosquito turns into adult insect.
When becoming an adult, mosquito requires a certain time for resting on the water surface to let its body to get stronger and dry out before being able to fly.
As a rule the duration of each growth stage (up to adult) depends on temperature and other factors of environment. Usually the lower the temperature, the longer lifecycle is. The length of life differs for different species, but in general it takes from 4 days up to 30.
In the below part of the article you will find out more about mosquito species mostly common for the US areas. Culex mosquitoes are one of the most annoying biting insects in America. For laying eggs Culex individuals prefer the water surface, either on fresh or lenthic water bodies. It can settle near people’s houses if there are some water reservoirs located near. It can be anything: flowerpots, buckets, ditches, swimming pools, etc. These mosquitoes like mostly calm places with no wind. House courtyard is ideally suitable place for propagation.
As a rule, eggs are laid during the night time. Culex mosquitoes make up eggs rafts once in three days (only grow-up individuals). Each raft contains up to three hundred eggs. Each egg is dark-colored, about 6 mm in length and 3 mm in width.
The egg of Culex mosquito turns into a larvae in one day. As opposite to Culex species, Anopheles group of mosquitoes’ eggs are not formed in rafts, they are laid singly. Another species, Aedes, oviposit on damp ground, mostly on places of salt water body’s shores, irrigated fields, etc.
Mosquito larvae or ‘wrigglers’ stay in water for seven – fourteen days. The term of staying in water depends on its temperature. Being on a water surface allows larva to breath, enriching their body with oxygen. The respiratory organ of mosquito larvae is a siphon tube, not all species have it. Anopheles mosquitoes don’t have a siphon tube, they have a breathing opening. To breathe they need to lie on a surface for some time during a day.
When growing, larva changes its skin coat four times. The period between shedding is called instar. At the time of fourth instar larva is twice more in size than it was during the egg phase. Its length is about 12 – 13 mm.
The fourth instar is the last phase of larva stage, after it the individual turns into a pupa.
Pupa is a transitional period from larva to adult insect that lasts from one to four days. The color of pupa is slightly lighter, compared with water. As a rule, pupae live on the water surface. Breathing is performed through a couple of breathing tubes or ‘trumpets’. The pupae don’t take any food.
In the end of the pupa phase an adult mosquito breaks the pupal case and lifts to the water surface. Here it takes some rest to dry off and become stronger.
The bites of mosquitoes differ in painful sensations. For example, Aedes mosquitoes’ bites are very painful. What is interesting, they bite mostly during the daytime, not in the night hours. They do not come to houses, biting outdoors, and their main attraction is different mammals, including humans. Also Aedes species are very good fliers, famous for their long-distance migrations.
Culex mosquitoes are also annoying biters, but their time for bites is gloaming and night hours. They easily enter animal dwellings for taking some blood meal. They bite mostly wild and domestic birds instead of animals and people. Some of Culex species are the transmitters or dangerous infections. For instance, Culex tarsalis spreads encephalitis (inflammation of the brain) to people and some domestic animals. Culex mosquitoes do not fly to long distances, only to one or two miles away from their homes.
Female individuals, appeared in the late summer usually search appropriate places for hibernation. In spring they wake up with the warm weather and continue their life cycle by laying eggs.
Culiseta mosquitoes are also among annoying biters that attack people in the evening or daytime in shaded places. The only carrier of malaria that affects people is Anopheles mosquito. It is met on all continents except Antarctica.