Mosquitoes, mosquitoes – profile, lifespan and mosquito species

Mosquitoes belong to the dipterans within the group of insects. Most of them are of slim build with long, thin legs. Not all mosquitoes suck blood. The most well-known native representatives are the mosquitoes (Culicidae) and the crane flies. Around 3,500 species of mosquitoes are known worldwide. We have around 50 of them. These can be divided into six genera:

Aedes species (flood gnats)

More than half of the native mosquito species belong to this genus. Since the year 2000, some species have been grouped in the genus Ochlerotatus. These mosquitoes often appear in large numbers in the high-water summer months on the Rhine, Danube and Elbe as well as on Lake Constance. Aedes mosquitoes have a strong migratory instinct. It is not uncommon for the insects to cover several kilometers a day. These mosquito species are characterized by a pronounced desire to bite, which is why they are by far one of the biggest pests. It is not uncommon for 50,000 eggs of these mosquitoes per square meter to be found in bodies of water. With regard to the breeding area, a distinction is made between:

Waldmücken

They live in swampy forest areas where breeding sites (puddles and ponds) appear after snowmelt and heavy rains. Wood mosquitoes already lay their eggs on moist forest soil. In contrast to the meadow and lowland forest midges, the wood midges hatch preferably in spring, when the forests have reached their maximum water level. Common types are:

• Aedes (Ochlerotatus) cantans
• Aedes (Ochlerotatus)
• A. communis
• A. rustic

Meadow and floodplain mosquitoes

Meadow and floodplain midges prefer to live in flood areas of larger rivers and lakes with temporary water level fluctuations. The Aedes mosquitoes are between six and ten millimeters long and usually have high-contrast scales. The females have a pointed abdomen.

• Aedes vexans: the most common species, also called Rhine gnat or meadow mosquito
• Aedes (Ochlerotatus) sticticus: second most common species, also called alluvial midge
• A. rossicus
• A. cinereus

Culex species

Six different species are represented in this genus. Among other things, the Culex pipiens, which can become quite annoying in the area of ​​human settlements, even indoors, and is therefore generally referred to as the house mosquito. Culex mosquitoes are usually brownish, have little contrast and are quite small (3-7 mm). In contrast to the Aedes mosquitoes, the female animals have a blunt abdomen. Most common species: Culex pipiens: also called common mosquito or northern house mosquito

Not all Culex species require human blood to reproduce. Some species prefer birds, others do not need to suck blood at all before laying eggs. Externally, the six species are difficult to distinguish from one another. House mosquitoes are extremely crepuscular and nocturnal insects, which is why they often become a nuisance in buildings at night in late summer and autumn. Hibernation is cold (but frost-free) with the highest possible humidity (sewers, garages, garden sheds, agricultural buildings). The Culex mosquitoes are not very picky when it comes to laying their eggs. They lay their egg boats in any accumulation of water that has existed for more than two weeks. Rain barrels, garden ponds, septic tanks, tin cans or clogged gutters are also possible.

Culiseta-Arten

The seven representatives of this genus are characterized by a large and strong stature (10-13 mm). Female mosquitoes are easy to distinguish from the house mosquito (Culex pipiens): They have a blunt-ended abdomen, spotted wings, white-ringed legs and are significantly larger. While some species live primarily in forests or near rivers, others prefer human proximity.

• Culiseta annulata: the most common species, also known as the large house mosquito or ringworm
• Culiseta morsitans

The Culiseta annulata is very similar to the house mosquito in its way of life. However, it is rarely a burden in buildings during the summer months at night. In autumn, however, the fertilized females enter stables or dwellings to hibernate and are quite active there even in winter.

Anopheles species (malarial mosquito, fever mosquito)

Anopheles mosquitoes are feared carriers of human malaria. But despite the occurrence of six Anopheles species in Germany, no cases of malaria transmitted by native mosquitoes have been reported for decades. On closer inspection, Anopheles mosquitoes can be identified by their posture when sitting on a surface. In contrast to the other mosquito species, their body is not aligned parallel to the surface they are sitting on, but their abdomen is slightly raised. The trunk, head and body form a straight line at an acute angle to the base.

• Anopheles maculipennis: also called fever mosquito
• Anopheles: messeae, atroparvus, claviger, plumbeus, algeriensis

The first three species are summarized in the Anopheles maculipennis group because they are very similar. They are the most common species of the Anopheles mosquito found in the Upper Rhine area.

Mansonia species (water ground mosquito)

The genus Mansonia is only represented by a single species. Unlike the other mosquito species, their larvae live more or less permanently under water during development and not on the surface. This is possible because their breathing tube is equipped with a sawing device, so they can drill into the air tissue of aquatic plants and extract air from there. Mansonia overwinters in the third larval stage, so it only settles in areas with permanently water-bearing waters. The reproductive mosquitoes then hatch from early summer. In contrast to the other species, these mosquitoes only have one generation per year.

Coquillettidia richiardii is relatively large and has a blunt rump. It is characterized by its dirty yellow color and is rarely found in large numbers.

Uranotaenia

Although these mosquitoes are most prevalent in the African and Mediterranean regions, they were first detected in Germany in 1994. So far, Uranotaenia has preferably bitten birds and only rarely humans. It often lives in the company of Culex pipiens and Anopheles in heavily silted permanent waters.

Uranotaenia unguiculata – Uranotaenia unguiculata is one of the smaller species of mosquitoes that is dark brown in color. This mosquito is easily recognizable by its silvery stripes on the upper side of the front body.

nutrition

Normally, mosquitoes only feed on sweet plant juices. Flower nectar is one of the most important carbohydrate sources for insects. Only the female mosquitoes need blood to produce eggs. The stinging apparatus is severely underdeveloped in males and therefore no longer capable of sucking blood. In numerous field and laboratory experiments, scientists have found that the female mosquitoes orientate themselves primarily on certain substances when looking for a host from which they can suck blood:

• exhaled carbon dioxide
• Body odors such as fatty acids, ammonia and lactic acid

The mosquitoes can follow the scent of the host with their fine olfactory organs until they finally find it. Depending on sensitivity, the bite of the female mosquito results in a more or less strong wheal formation. These wheals are caused by the fact that the mosquito releases protein-containing saliva secretion when it bites, which prevents blood clotting. This is the only way for the mosquito to suck blood at all. While mosquitoes are feared as carriers of dangerous diseases in the tropics and subtropics, they are of little or no importance to us as disease carriers. However, an infection via a mosquito cannot be completely ruled out.

life cycle of the mosquito

1. The egg
Female mosquitoes lay between 30 and 300 eggs exclusively in standing water. This can be a lake or garden pond, but also a rain barrel. The surface tension of still water and a few air bubbles between the eggs are enough to keep the egg boats, into which the eggs are glued together, from sinking.

2. Larvae
After three to five days, larvae hatch from the mosquito’s eggs. Although the mosquito larvae develop in the water, they do not have any organs that allow them to breathe under water. Mosquito larvae have a breathing tube on the penultimate segment of their abdomen through which they can take in air – and thus oxygen. The larvae therefore usually hang upside down under the water surface. Algae and microorganisms in the water serve as a source of food. If danger threatens, the mosquito larvae are very agile and twitch out of the danger zone in snaking movements. The larvae moult four times during their lifetime. Depending on the food supply, it can take between one and three weeks for the larva to pupate.

3. Pupae
While the pupae of many insects remain in a rigid cocoon, the mosquito pupae are still mobile. They float beneath the surface of the water and breathe through two small breathing tubes. Although the pupae no longer eat, they can still flee from danger. The pupal stage of the mosquito lasts only a few days. Male mosquitoes hatch slightly earlier than females. Once mosquitoes are able to fly, they are ready to reproduce.

reproduction

At dusk, the male mosquitoes form large swarms. It is not uncommon for more than a thousand individual insects to be found in these swarms. Female mosquitoes fly into these swarms. With their excellent sense of hearing, the males localize the female mosquito. This is very easy for the mosquitoes, because a female generates a buzzing sound of around 550 Hertz, while this is around 600 Hertz for males. Once the right partner has been found, both increase their buzzing frequency to 1200 Hertz until after mating.

If the female mosquito is fertilized, it is imperative that it consume proteins (hemoglobin) and iron. Because without these substances, most mosquito species cannot develop eggs. Once the mosquito has found the right host, it takes about 0.005 ml of blood with one bite. After digesting this (1-2 days), she starts laying eggs. A female mosquito can repeat this cycle multiple times.

Life expectancy

Female mosquitoes have a life expectancy of about six weeks. Males usually die much earlier. The exception are the female mosquitoes, which hibernate fertilized.

hibernate

As soon as temperatures drop below freezing, mosquitoes stop flying. Male mosquitoes do not survive the winter. Fertilized females seek a moist, cool place to hibernate. They fall into a torpor that lasts until the first days of spring. Then their spirits awaken and the cycle starts all over again with the laying of eggs. An exception is the Mansonia, which overwinters as a larva in water.

Conclusion
There are around 50 different types of mosquitoes in Germany. They are easily recognizable by their delicate physique and long, thin legs. Female mosquitoes have a specialized mouthpart, the proboscis, which they can also use to sting when they need blood for reproduction. The six different genera of mosquitoes differ according to their breeding area. While Uranotaenia and Mansonia are found only in permanently aquiferous bodies of water, Aedes and Anopheles mosquitoes live in the flood plains of large rivers. The common house mosquito (Culex species) and the large house mosquito, which belongs to the Culiseta species, have adapted to human settlements.