On 20th August, 1897, Sir Ronald Ross, a British doctor discovered that female Anopheles mosquitoes were responsible for the transmission of parasites between human beings causing a life threatening disease, malaria. To commemorate this feat, the London School of Hygiene and Tropical Medicine started celebrating World Mosquito Day annually on 20th August, since 1930. World Mosquito Day is being observed to raise awareness about the mosquito-borne diseases, particularly malaria that takes away millions of lives every year, and emphasize our contribution to contain the spread of this pesky insect.
The word mosquito is originated from the Spanish language meaning a little fly. Just like bees, mosquitoes too, feed on plant nectar. Contrary to the belief that mosquitoes feed on human blood to survive, male mosquitoes do not feed on blood at all. It is only female mosquitoes that draw blood since a specific protein present in the blood helps in the development of eggs prior to laying the clutch.
Of more than three thousand species of mosquito known, only a few hundred are harmful to human beings. On one side, mosquitoes are responsible for carrying and transmitting dreadful diseases, on the other, they play a significant role in the ecosystem as a food source for many animals.
Mosquitoes are considered to be the deadliest of all the animals causing million of deaths by acting as a vector in transmission of diseases like Malaria, Dengue, Zika, Chikungunya and others. Different species of mosquito spread different diseases; likewise different species are active at different times of the day/night. Mosquitoes might not be eliminated completely but we can control and prevent to reduce the harmful impact on our lives, to certain extent.
Some interesting facts about Mosquitoes
- Moon serves as night time navigation for mosquitoes. Hence, they get attracted towards lights, confusing with moon.
- Mosquitoes have been for quite long, somewhere from Triassic period – millions of years. They play a significant role in our ecosystem, as a food source for many birds, spiders, salamanders, frogs, fishes, other insects, and also act as a pollinator.
- Male mosquitoes survive for an average of 10 days but female mosquitoes live for an average of 40 to 60 days, sometimes even much more, depending on the species.
- Mosquitoes do not have teeth but their proboscis (needle-like straws) has several saw-like ridges to penetrate through skin. Similarly, they do not have ears but can detect sound vibrations through their antennae. However, they do have compound eyes, which are best for detecting motion.
- While hunting for prey, mosquitoes are attracted by carbon dioxide, lactic acid and octenol released by our breath and sweat. They can sense carbon dioxide from as far as 75 feet. In addition, body heat and humidity around helps them in identifying the target. Once located, they start hovering around with buzzing sound produced by flapping wings at the rate of five hundred beats per second. However, these are the female mosquitoes that come for feeding on blood, while male mosquitoes are busy like bees, feeding on nectar. Blood proteins are required by mosquitoes to fertilize their eggs, before laying the clutch, a set of 100 -200 eggs at a time. Mostly they lay eggs in standing water, however some species lay on damp soil which is prone to flooding, and then there is a species of mosquitoes that even drop the clutch in pitcher-plant.
- Bites of mosquitoes are not just limited to human beings but certain species bite dogs, cats, birds, reptiles, amphibians, and domestic animals.
- Though this ‘little fly’ weighs hardly 2.5 milligrams but can draw blood up to three times of their body weight. During the process of sucking blood, mosquito saliva lubricates their proboscis to glide into our skin.
- Their saliva carries anticoagulant and proteins. These proteins act as foreign substance to our body and to counteract our immune system responds, causing allergic reaction (itchy lump).
- The design of their proboscis has inspired scientists to design less-painful hypodermic needles, examine strategies to make needle insertion easier, and create insertion guides to better place tiny electrodes into the brain. Such nature inspired (biomimetic) technology is now studied under Biomimicry.
Some measures to take to control and prevent breeding and spread of mosquitoes
- Cover all water containers in the house or workplace, to avoid egg-laying by the mosquitoes
- At least on weekly basis, empty and dry up water tanks, containers, coolers, birdbaths, pets’ water bowls, plant pots, drip trays and the like
- From open spaces, remove any discarded item that can collect rain water
- Avoid clogged gutters or drainage from roof top
- For biological control, larvivorous fish like Western Mosquito fish (Gambusia affinis), also known as Guppy fish can be introduced in ornamental water tanks or gardens
- Bacteria, Bacillus thuringiensis (Bt H-14) acts as biological larvicide in stagnant water and poses no danger to humans, non-targeted animal species, or the environment when used according to instructions
- For chemical control, larvicidal and adulticidal chemicals can be used
- For personal protection –
- use insect repellents
- wear light-coloured clothes, preferably, that cover the body as much as possible
- use mosquito nets while sleeping
- use barriers indoors as screen over windows and doors, and most importantly
- patients infected with Dengue, Chikungunya, or Zika virus, their household members, and community must follow personal preventive measures