The looming spring and summer months will mean a great deal to a great many. You see, most of us are a little uneasy in the cold. South Africans fancy themselves a warmer clime and this also means that, come September, we’ll be able to open our doors and windows without fear of any hypothermic repercussions. It will, however, invite insects and the remnants of deciduous foliage into our homes. The pleasant weather will also see an uptick in the activity of many, many unwanted solicitors. But… the kinder climate will invariably mean the return of man’s greatest gripe.
They ruin a good night’s sleep far better than the most aggressive spate of food poisoning ever could. They irritate the skin as much as an accidental brush with ivy or nettle does and they most certainly require a hefty effort to eliminate. The culprit in question is indeed the hated, reviled and loathsome mosquito. The only love these critters will ever receive is from an entomologist who had no other choice but to study their behaviour, breeding patterns and general lifecycles. They are at the pinnacle of universal annoyance.
Mosquitoes have undoubtedly been a pest during the entirety of their 226 million year existence. The truth, however, about these insects, in some parts of the world, is far more sinister than their high-pitched flutter would imply. While most of us battle to whack a few with a pillow at night, many suffer and even perish after being probed by the creature’s elongated mouthparts. We’re all familiar with the dreaded, infectious disease that is malaria and any accompanying symptoms that may lead to a death far more uncomfortable than it deserves to be.
The 20th of August is World Mosquito Day and it is by no means observed to celebrate these perennial nuisances, but to rather venerate the British medical doctor, Sir Ronald Ross. In 1897 Ross discovered that female mosquitoes transmit malaria between humans. Ross himself declared shortly after his discovery that this day should be observed as such and it likely makes it one of the longest-running secular observances in modern history. He received the Nobel Prize for Physiology or Medicine, making him the first British Nobel laureate.
Now, you’ve probably heard that any living thing has an ecological purpose, but you’ve also likely battled to figure out what the mandate of a mosquito is in any given system. To many their solitary purpose is to piss humanity off, but they are critically important to aquatic ecology. There is a reason why they proliferate so, well, prolifically. If every mosquito would go extinct this very second, an untold number of fish and birds in a variety of biomes would see their numbers drop drastically. Mosquito larvae are an important food source for many animals on Earth.
It is therefore probably a given that not many have given much thought to these minute carters of pestilence. Our knowledge, as the general populace, is likely a little undersized. We know what they look and sound like and we may know that malaria is responsible for around five percent of annual deaths on the African continent. In fact, the World Health Organisation estimates that a disproportionate 92% percent of malaria cases and 93 percent of malaria deaths occurred in Africa in 2017. Here are a few interesting factoids about mosquitoes.
- There are around 3500 known species of mosquitoes but only a few hundred of these consume human blood.
- Male mosquitoes are more likely to feed on plants. A female mosquito would need a serving of blood before laying eggs.
- A mosquitoes’ saliva contains an anti-coagulant. This is what induces an allergic reaction in humans that will make the skin itchy. It also makes it easier for the insect to suck any blood up its proboscis.
- The oddly have a preference for beer drinkers.
- They are also attracted to the carbon dioxide, lactic acid and octanol found in our breath and sweat. They also sense the heat and humidity radiating from our bodies.
- Females prefer to lay their eggs in shallow stagnant bodies of water and the best time to avoid the insects is during the afternoons when they cower from the heat.
- Around 250 million people are infected with malaria each year. About a million of these will succumb to the disease – most are children.
- Since the implementation of widespread insecticide-treated nets, there has been a reduction of incidence by up to 50 percent.
- They are known as ‘vectors’ and can be carriers of multiple deadly diseases like Zika and Dengue and yellow fever. This is why they are known as the world’s deadliest animals.
- The use a special organ called the maxillary palp to detect any carbon dioxide another organism would emit.
- Mosquitoes generally have a maximum lifespan of up to two months.
- A mosquito can drink up to three times its weight in blood.
- Females will lay eggs three times during their lifespan and would lay clusters, called raft, of up to 300 eggs at a time. They spend the first ten days of their lives in water.
- They are one of many insects that hibernate. They typically prefer temperatures from the middle-20s and upwards and tend to shut down when the temperature drops below 10°C.
- Their beat between 300 and 600 times a second, but generally only achieve flying speeds of up to 2.5khp.