We often view mosquitoes as bloodsuckers that do nothing but make our lives miserable. However, mosquitoes do have ecological functions. From pollination to ant puke, the secret life of mosquitoes is both bizarre and ecologically important. Mosquitoes have many functions in the ecosystem that are overlooked. Indiscriminate mass elimination of mosquitoes would impact everything from pollination to biomass transfer to food webs. Worldwide there are about 3,500 mosquito species, many of which want nothing to do with biting humans or any other animal. Even in species that bite, it is only the females that do so and just to develop their eggs. The fundamental food of all adult mosquitoes is plant sugar and its associated nutrients, most often in the form of floral nectar. In the process of looking for nectar, mosquitoes pollinate many of the flowers they visit — this is one of the most commonly overlooked ecological functions of mosquitoes. Mosquito pollination is likely far more common than we realise. There is evidence that mosquitoes function as generalist pollinators in some plant families, and there are many known instances of mosquito pollination that are simply overlooked. Mosquito pollination was observed as far back as the 19th century. Mosquito pollination is hard to see, as most mosquitoes visit flowers near or after dusk and human presence disturbs mosquitoes from nearby flowers. In the Arctic, plants make use of vast hordes of nectar-hungry mosquitoes for pollination during the short growing season. We generally share that Malaria infects some 247 million people worldwide each year, and kills nearly one million. Mosquitoes cause a huge further medical and financial burden by spreading yellow fever, dengue fever, Japanese encephalitis, Rift Valley fever, Chikungunya virus and West Nile virus. They live on almost every continent and habitat, and serve important functions in numerous ecosystems. “Mosquitoes have been on Earth for more than 100 million years,” says scientists, “and they have co-evolved with so many species along the way.” The connection between mosquitoes and flowers is ancient and has likely had a strong influence on mosquito evolution. Genetic evidence supports a rapid increase in mosquito diversity corresponding with the appearance of flowering plants. Mosquito scales have been found in flower fossils from the mid-Cretaceous era. Mosquitoes locate flowers by a variety of cues including odour and vision, and recent research has discovered that some of the odour constituents of certain flowers that mosquitoes feed on (and pollinate) are shared with humans. One interpretation of this is that to mosquitoes, some flowers may smell like humans, possibly indicating the evolutionary origins of why some mosquitoes take blood. While less ecologically important than pollination, mosquitoes also consume plant sugar that has been processed by other insects. Plant-sucking insects such as aphids excrete a sugary waste product known as honeydew, which is exploited as a food source by many insects, including mosquitoes. But honeydew is hard to find in the environment. Mosquitoes have solved this problem by using the smells emitted by microbes that live in the honeydew to locate it. When a mosquito inserts its mouthparts into an ant’s mouth and strokes the ant’s head with its antennae, it tricks the ant into regurgitating and sharing its honeydew. Additionally, honeydew is famously consumed by many ants, which farm aphids to collect honeydew. An ant can, through strokes of its antennae, induce a compatriot that has recently eaten honeydew to regurgitate and share some of its meal. Some mosquito species have learned to exploit this for their own benefit. The Mosquito serves as Biomass transfers. Mosquito larvae grow by consuming microorganisms such as algae and microbes that decompose decaying plant material. Larval mosquitoes contribute to aquatic food chains by serving as food sources for many predators, including fish and birds. The Mosquito serves as Biomass transfers. Mosquito larvae grow by consuming microorganisms such as algae and microbes that decompose decaying plant material. Larval mosquitoes contribute to aquatic food chains by serving as food sources for many predators, including fish and birds. If a mosquito survives to adulthood, it flies away from its aquatic habitat. This transfers the mosquito’s biomass (its material weight) to the terrestrial ecosystem. Adult mosquitoes are eaten by many creatures including birds, bats, frogs and other insects. Adult mosquitoes that die (or are eaten and excreted) then decompose, turning the microbes they consumed as larvae into nutrients for plants, completing another important ecological function. Wiping out a species of mosquito could leave a predator without prey, or a plant without a pollinator. And exploring a world without mosquitoes is more than an exercise in imagination: intense efforts are under way to develop methods that might rid the world of the most pernicious, disease-carrying species (see ‘War against the winged’). Scientists reported that Mosquitoes are delectable things to eat and they’re easy to catch. In the absence of their larvae, hundreds of species of fish would have to change their diet to survive. This may sound simple, but traits such as feeding behaviour are deeply imprinted, genetically, in those fish. The mosquito fish (Gambusia affinis), for example, is a specialized predator — so effective at killing mosquitoes that it is stocked in rice fields and swimming pools as pest control — that could go extinct. And the loss of these or other fish could have major effects up and down the food chain. Many species of insect, spider, salamander, lizard and frog would also lose a primary food source. It has been reported that birds produced on average two chicks per nest after spraying, compared with three for birds at control sites.
Most mosquito-eating birds would probably switch to other insects that, post-mosquitoes, might emerge in large numbers to take their place. Other insectivores might not miss them at all: bats feed mostly on moths, and less than 2% of their gut content is mosquitoes. As larvae, mosquitoes make up substantial biomass in aquatic ecosystems globally and they abound in bodies of water ranging from ephemeral ponds to tree holes. They feed on decaying leaves, organic detritus and microorganisms. Species of mosquito (Wyeomyia smithii) and midge (Metriocnemus knabi) are the only insects that live there, along with microorganisms such as rotifers, bacteria and protozoa. When other insects drown in the water, the midges chew up their carcasses and the mosquito larvae feed on the waste products, making nutrients such as nitrogen available for the plant. In this case, eliminating mosquitoes might affect plant growth. Mosquito larvae can be found in most types of freshwater, from temporary snow-melt pools to lakes. They can even be found in a few types of saltwater habitats such as crab burrows. One of the more interesting habitats that mosquito larvae can be found in are the pitchers the carnivorous plant Sarracenia purpurea. These pitchers are filled with water and decomposing insects that provide food to both the plant and the mosquito. The digestive enzymes in this plant are too weak to dissolve the mosquito larvae. Several mosquito species place their eggs in the water that collects between the leaves of tropical plants in the Brazilian Atlantic forest, and the larvae of some other mosquitoes attach themselves to the roots of aquatic plants to breathe. In 1974, ecologist John Addicott, proposed that as the larvae feed, they keep down the numbers of the dominant species of protozoa, letting others persist. The broader consequences for the plant are not known. A stronger argument for keeping mosquitoes might be found if they provide ‘ecosystem services’ — the benefits that humans derive from nature. Evolutionary ecologist Dina Fonseca, says people being bitten by no-see-ums or being infected through them with viruses, protozoa and filarial worms would love to eradicate them,” But without mosquitoes, thousands of plant species would lose a group of pollinators. Humans have made many concerted, if not always effective, efforts to eliminate mosquitoes. The more successful attempts include the eradication campaign against Aedes aegypti in the early 1900s, which relieved yellow fever enough to allow the completion of the panama canal; and the use of the larvicide paris green to rid Brazil of the malaria vector Anopheles gambiae by 1940. Application of the adulticide ddt allowed the united states to be declared free of malaria in 1949. But the chemicals sprayed then are banned in many countries now. “we can’t mount those top-down, military-style efforts today,”. “And we don’t have ddt any more. Mosquito control using less-toxic chemicals is key to keeping the insects in florida and parts of southeast Asia and latin America at tolerable levels. Worldwide malaria control in 2010 requires about US $1,880 million for indoor residual spraying and $2,090 million for insecticidal nets. “It’s a complicated business, and that’s why we still have mosquitoes,” nasci says. “they’re not going anywhere.” researchers are developing alternative mosquito-control methods. Scientists are working to reduce diseases caused by mosquito and balance ecosystem. Mosquitoes are also the world’s deadliest animal and cause immense suffering. Ideally, we should maintain the ecosystem functions of mosquitoes while also reducing disease burden. Not all mosquito species are responsible for spreading pathogens. Targeting specific species or making the mosquitoes themselves immune to pathogens and thus unable to spread them would protect humans while keeping the ecosystem function of mosquitoes intact. In a world of collapsing ecosystems and declining pollinator populations we need all of the help we can get. This includes acknowledging the secret lives of mosquitoes and more sophisticated mosquito control strategies that protects their ecosystem functions. The World Mosquito Day is celebrated on August 20th every year marking the occasion when Sir Ronald Ross discovered that female mosquitoes transmit malaria between humans. The malarial parasite was found in the gastrointestinal tract of a female mosquito. The discovery allowed scientist to better understand the role of mosquitoes in the disease. It also provided a starting point for prevention. In 1902. Ross became the first British person to be awarded the Nobel Prize for Medicine. There are over three thousand species of mosquitoes in the world today. Of those, only about three cause serious diseases. The most prevalent diseases are malaria, dengue fever, West Nile, Yellow fever, Zika virus and Encephalitis. The London School of Hygiene & Tropical Medicine holds Mosquito Day celebrations every year, including events such as parties and exhibitions, a tradition dating back to as early as the 1930s. According to the latest World malaria report, released on 30 November 2020, there were 229 million cases of malaria in 2019 compared to 228 million malaria cases in 2018. Further, as per WHO, 19 countries in sub-Saharan Africa plus India bore almost 85% of the global malaria burden in 2019. Of them, only India reported any progress in reducing the number of malaria cases. (Interestingly, Algeria was declared malaria-free last year). According to the WHO, “Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes.” Importantly, it is preventable as well as curable. In 1897, a British medical doctor named Ronald Ross discovered that the female Anopheles mosquitoes are responsible for spreading malaria. Ross was born in the Almora district of India’s Uttarakhand. He studied in London and came back to India to work on malaria from 1882 to 1889. He found the link between mosquitoes and malaria transmission 15 years into his studies, and was awarded the medicine Nobel Prize in 1902 for describing the complete life cycle of the malarial parasite. World Mosquito Day is observed every year on August 20 in recognition of his work, and even then the eradication of malaria is a major part of its awareness campaign. The London School of Hygiene & Tropical Medicine holds Mosquito Day celebrations every year, including events such as parties and exhibitions, a tradition dating back to as early as the 1930s. The theme of World Mosquito Day 2021 is “Reaching the zero malaria target”. On World Mosquito Day 2021, know which mosquito is responsible for what disease in humans. In humans, malaria is caused by five species of parasites of the genus Plasmodium. Of these, P. falciparum accounts for the majority of malaria cases and deaths because of the severity of the infections it can cause (although infections of P. vivax have also been known to be dangerous). When a female Anopheles mosquito carrying a Plasmodium parasite bites a human, the parasite is transmitted through the skin. First, it invades first the liver through asexual reproduction and then targets the red blood cells. As a result, the human develops symptoms like fever with chills and anaemia, etc. If left untreated, malaria can kill. At present, a major barrier to eradicating malaria is that malarial parasites have developed resistance against commonly used drugs to treat them, including chloroquine, sulfadoxine/pyrimethamine and even to the newer artesunate-based combination therapies. In the absence of an effective vaccine, it’s crucial that we find a way to restore these drugs’ potency against the parasite or develop new drugs that can be effective. The ongoing novel coronavirus pandemic hasn’t made matters easier, even if the world has developed (even temporarily) a heightened awareness of the effects of infectious diseases. Since the virus is new, we’re still discovering more about it even as we’re working towards a vaccine. So in the meantime, researchers have been repurposing vaccines and other fever-curing drugs already approved by various regulatory bodies to resist COVID-19. This is how hydroxychloroquine, a very important antimalarial drug, hit the limelight and which India’s apex medical research body has recommended to the country’s healthcare workers as a prophylaxis, even if there is no evidence that it can effectively prevent COVID-19. On the flip side, however, hydroxychloroquine tablets have become harder to find and use in places where chloroquine still remains effective against malarial parasites. Additionally, and even though the current pandemic situation is serious, controlling malaria is also very important but has often been sidelined in the headlong rush to avoid the novel coronavirus. Both COVID-19 and malaria patients have fever, but more people with fever get tested for COVID-19 first before malaria. As a result, malaria diagnosis and treatment may get delayed. There is no vaccine to prevent or cure malaria. One, designated RTS,S/AS01 and named Mosquirix, is currently undergoing clinical trials, after having displayed partial protection against malaria in young children. Even though it’s easier said than done in the throes of a pandemic, it’s important that we keep up precaution, prevention, early detection and effective treatment, together with mosquito control efforts, to vanquish malaria. To lower chances of getting malaria, we must follow the following steps (a) Keep water from stagnating (mosquitoes need stagnant water to lay their eggs) (b) Declutter any piles of junk (c) Cover water tanks, wells and buckets (d) Keep your surroundings clean (e) Sleep in well-screened areas at night (f) Use a bed-net and mosquito repellent to keep mosquitoes away (g) Wear long-sleeved dresses that cover the arms and legs to avoid mosquito bites.
( While Bilkees Nazir is a Research Scholar at the Department of Zoology University of Kashmir Hazratbal Srinagar, Dr Bilal A Bhat is an Associate Professor at Associate Professor at S K University of Agriculture Sciences & Technology-SKUAST Srinagar. Views are their own)