The Anopheles gambiae are a class of insects known for their parasitic nature, and they are believed to have the ability to spread malaria. Over years, scientists have taken their time to study these insects and find ways and means of controlling them. They mostly live in the tropics, where both the climate and humidity are conducive for their existence. Historically, they caused the deaths of most missionaries, who conducted their work in Africa. Today, malaria is still a threat to most people in Africa and Asia. The annual death rate resulting from malaria is higher than that of HIV/AIDS and Cancer in the two continents. Understanding the life cycles, feeding habits and reproduction cycles is the best way to eradicate the killer insects. However, not all species of the Anopheles gambiae affect human beings. The exceptional kind feed on animal blood and to some extent fruit syrup. The one that has drawn interest is one that feeds on human blood. This species spread malaria by passing over the bacteria present in their saliva. Further classification reveals that the female species is the one responsible. Today, there exist different methods and ways of controlling the insects. They have helped either control the insects or cure the malaria disease. It has been discovered that the insects have developed resistance and more studies need to be done to control it further.
The study of this class of animals involves understanding their history of development and their life cycles. It would also be particularly beneficial to understand their body structures, habits, behavior mechanisms, and their feeding habits. The insects’ history would help to determine their origin and the conditions suitable for their existence. It also helps the factors that accelerate their development and those that may harm them and their young ones. Understanding this helps in their control and management. The feeding habits, if well understood, would also help with controlling them through starving them or poisoning their foods and their habitats. The life cycles of insects are extremely valuable as they ensure continuity of the insects’ generation. For the scientist, trying to control harmful insects such as this, it plays a pivotal role as it becomes easy to eliminate the insects by breaking their life cycles. The study of insects may also be a subject of interest among the scientist. In the course of their study, it would be particularly beneficial to understand the different types of insects in different classes. Studying about the Anopheles gambiae would be no exception. It would be necessary to know and understand the different types of insects and their effects on the human health.
History of Anopheles Gambiae
In the 1930’s, the Anopheles gambiae invaded Brazil, leading to the yellow fever epidemic of 1938-1939. The control program was at this time successfully handled by the Brazil Government with the assistance of the Rockefeller International. The disease was at this time not particularly well known or understood as it is today. The control of the parasites and eradication of the disease was a strenuous activity that involved the community and the government. The government and its associates first educated the public about the yellow fever diseases and its dangers. They involved health experts in spreading the 17D virus vaccine that helped to protect people living within the tropical forests. The availability of primates in the forests and a good conducive climate aided the spread of the parasites. The Congo forest is affected in the same way due to similar factors. Today, the Latin America countries have succeeded in eradication of the parasites. In the sub-Saharan Africa malaria is still prevalent and is related to most deaths of children below age of five. This is due to the high poverty rates and lack of knowledge about the parasite (Bates, 1970).
Life Cycles of Anopheles Gambiae and their Structures
The Anopheles gambiae undergoes four life stages namely the egg, larva, pupa and imago, which is the adult stage. The first three stages, which take about 14-15 days, are general aquatic ones. The life span of an adult is about 14 days but it can live more in captivity. The three stages are different from each other in terms of character. The rate of production depends most on the prevailing temperature. During the high temperature seasons, the rate is higher as the rate of hutching increases (Gilbert, 2011).
The eggs are usually small with floats on both sides as they are laid singly and on water. In every oviposition, the adult lays about 50-200 such eggs. The eggs easily dry up in excessive heat, as they do not have hardened shells. The eggs normally take about 2-3 days to hatch but can take up to 3 weeks in cold conditions.
They have well developed bodies with head, thorax and abdomen. The mouth on the head has brushes that are used for feeding. They lack legs and respiratory siphons present in other mosquitoes. They are usually found on the surface of clean, unpolluted waters. The spiracles, located on the eighth segment of the abdomen are used for breathing. The larvae spend their time feeding on bacteria and algae. They develop in four stages that take 7 days when the temperatures are conducive. Molting occurs at the end of every stage allowing for further development.
They have their head, and thorax merged to form the cephalothorax. The abdomen is curved underneath to form the comma shape. They have to be on the surface of the water to breath. They breathe using the respiratory trumpets on the cephalothoraxes. The dorsal surface of cephalothoraxes splits to give way to the adult.
The mosquitoes have three body parts, the head, thorax and abdomen. The head is adapted for sensory functions and feeding. The sensory functions are played by the eyes and the antennae, which detect different types of stimuli. The adult anopheles mosquitoes are distinguished by the presence of white and black scales on their wings and the availability of pulps on their fore heads. The thorax has three pairs of legs and wings attached to it for movement purposes. The abdomen is used for digestion of blood and nectar and as the storage facility of the developing eggs. The mosquitoes usually start mating immediately after they are thoroughly developed. The males feed on nectar, unlike the females, which need blood for egg development in their abdomens. The females lay eggs all their lifetime (Trufanov, 2010).
The anopheles mosquitoes are usually found in swampy and bushy areas. They usually prefer these areas as they offer good conducive areas for laying eggs. The mosquitoes prefer the unpolluted areas, which are not harmful to their eggs. Calm areas where the stagnant water is not disturbed are as well preferred areas. The salinity of the water is not much considered when choosing their habitat as they can survive in both salty and fresh water.
The anopheles mosquitoes spread the plasmodium bacteria that cause malaria or yellow fever. The disease affects human beings and other animals. The bacteria are spread through mosquito bites and can be dangerous if not controlled. The disease is most common in tropical areas, where the mosquitoes have better breeding grounds. The disease can be controlled by the use of nets, vaccination and destroying of the parasites breeding areas. The female mosquito, which feeds on blood, spreads the disease (Clements 2012).
Differences Between the Male and Female Anopheles Gambiae
The mosquitoes have no many physical differences, and, thus, it may be difficult to recognize them. However, by placing them under the microscope, the differences can be easily detected. The females can be recognized by their black and white spots on their feathers. They can be also established by the smooth proboscis unlike the males, which are bushy. They can also be distinguished by their feeding habits. The males feed on nectar and fruit juices, while the females feed on human and animal blood. The lifespan of the female is usually longer than that of the males. The males usually die after mating. The females are found on the skin on their hosts trying to get blood; this is quite different from the males, which are only found on plants (American Mosquito Control Association 2001).
The anopheles mosquitoes are found within the tropical belt all over the world. They are usually found in the heavily forested areas, stretching from the Latin America belt across Africa and to the Asian belt. They are usually associated with the warm temperatures in these areas and the wet climate. The availability of apes and primates in these regions favors their development and spreading. The areas around the Congo Forest are most preferred due to their calmness and a good conducive climate.
Patterns of Feeding and Resting
The mosquitoes have different modes of operation. Some of the mosquitoes like to feed at night, while others feed during daytime. Those that feed at night are usually controlled using nets, while those that feed during the day are controlled using insecticides. The feeding habits can also be classified as indoors or outdoors as it is with the resting. In this category, some will east and rest outside, while others will eat and rest inside. It can also be vice versa with those feeding outside and resting indoors, and those feeding indoors and resting outside. This behavior depends on the genetical make up or the climatic conditions prevailing in the region (Wathern, 1998).
Malaria Diagnosis and Treatment
Malaria diagnosis should be accurate to determine the correct treatment. The type of treatment depends on the region, severity of the disease and resistance in the diseases history. In some regions, vaccination is used to protect people against the disease. The treatment offered should be curative to prevent the development of the resistance. In most areas, though, the disease has been eliminated. People travelling to infected areas are advised to take anti-malaria drugs.
Interesting Facts about Anopheles Mosquito
The most intriguing facts about the mosquitoes are that there are about 430 species of the insects but only 30-40 species cause malaria. Most of the species are resistant to control chemicals and need new developments. The mosquitoes have been noted to be active immediately after darkness and early morning, before dawn. In case the mosquitoes are imported in cargo, they usually cause airport malaria among the passengers (Trufanov, 2010). People, travelling from infected areas to uninfected ones, always cause the spread of the disease and introduce the disease.
How Long Do Anopheles Mosquitoes Live
The male anopheles mosquitoes live for about a week. A female mosquito can survive up to a month. They feed on nectar and other sugar sources. Female anopheles mosquitoes can survive up to a month, but most do not typically live longer than one to two weeks. Their chances of survival depend on temperature and humidity, but also on their ability to obtain a blood meal.
Anopheles Versus other Mosquitoes
The anopheles mosquitoes are known to rest with their abdomen raised up unlike the other mosquitoes, which rest with their bodies parallel to the surface. The anopheles is also distinguished by the appearance. They have white and black spots on their bodies while others are straightforward. The anopheles mosquitoes have extended pulps as compared to the other types.
The anopheles mosquitoes have life spans ranging from one week to one month. This is determined by the availability of food, the climatic conditions and the survival of the host’s defensive mechanism. The males usually have short lives as they die after mating. They survive better in areas far from human settlements, and which are believed to be unpolluted. In the polluted environments, they usually have short life span and their rate of reproduction is slow. The wet and hot climates encourage their developments, as there is stagnant water that provides the breeding ground, while the high temperatures favor the survival and hatching of eggs (Trufanov, 2010).
Choice for Meals
The males are known to feed primarily on nectar and fruit saps from plants. The females, on the other hand, have to feed on blood from either animals or human beings. The blood is known to provide the proteins, which are much needed in the development of the eggs within the female abdomen. The mosquitoes tend to like the blood of the primates.
Resistance to Insecticides
The mosquitoes with time become resistant to insecticides. This happens if the same insecticide is used for a long time or inconsistently. It is caused by the mutations, which occur in the insects’ genetic make up, leading to adaptability. These changes are observed in the future generations of the infected mosquitoes. The adaptation allows them to resist to control measures and environmental pollution. Adaptations of this kind make the controlling of the parasites difficult and more powerful chemicals have to be used (Wathern, 1998).
Control of anopheles mosquitoes
The anopheles mosquitoes can be controlled using different methods and ways. The use of chemicals is the most common and worldwide used. They can also be controlled using mosquito nets, which are sometimes sprayed with the insecticide to ensure that any mosquito that encounters the net dies. Draining of stagnant water around the residential areas helps to destroy the eggs and larvae and get rid of the breeding zones. This helps in destroying all the possible ways of regeneration. It also assists in ensuring that the mosquitoes’ future generations are reduced in numbers ( Holstein, 1954). Burning of grasses and the bushes is another way of controlling and eradicating the insects from the environment. The clearing of the bushes is also an alternative. Burning of mosquito coils and chips are additional ways of controlling mosquitoes domestically. It has been found effective in most areas. The use of mutative chemicals and the wolbacha pipients can also be effective.
Role of anopheles in malaria transmission
The female anopheles mosquito is associated with the spread of malaria. It is possible as the mosquito carries plasmodium bacteria in its saliva. During the sucking of blood from the host, the mosquito injects the bacteria into the host’s blood stream where it develops and finally blasts to full malaria (Silver, 2007). The insect itself is not affected by the bacteria as its saliva has chemicals that prevent this from occurring. The male mosquito has no responsibility in spreading the bacteria, as it does not feed on blood.
Effects of Anopheles Mosquito
The anopheles mosquito has different effects on both the animals, humans and plants. The male anopheles mosquitoes destroy fruits and other plants as they suck sup from them. This leads to poor production. The females have the biggest effects on man and animals. Apart from spreading malaria, they cause itchy skin, which makes the victim uncomfortable. They also cause anemia by sucking blood from their victims (Wathern, 1998).
Wolbachia pipients and the anopheles mosquito
The Wolbachia Pipients is a bacterium that largely affects the invertebrates’ reproductive system. The bacterium leads to death of the males leading to generation degeneration. It may also lead to the development of infertile males leading to unproductive fertilization. The anopheles mosquitoes are widely affected by the bacterium which is threatening their existence. The scientists studying the insects are considering using this bacterium and other mutative elements to control insects. The effects of this bacterium have been observed in the control of anopheles mosquito in America and Brazil, where malaria has been totally eradicated (Joseph 2005).
The study of the anopheles mosquitoes can be an attractive thing to do. Understanding their life cycles and effects can help a virtuoso in dealing with the killer insects. The further understanding of the same can help distinguish the anopheles mosquitoes from other mosquitoes, and thus help the people control them. It would be also crucial to understand their control measures and treatment of the malaria disease can help save many lives in the vats tropical belts through the world and especially the sub Saharan Africa and the Asian continents. The use of technology aided control measures, like mutation, would help enhance non-chemical control to protect the environment. It is up to all the scientists and the people in this field to prevent the recurrence of the Brazil like epidemic. The areas around the Congo Forest could be the best study area for any scientists willing to study all about the insects. It is also noteworthy that the people be trained on how to eradicate the disease and prevent it from recurring.
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