The life of a mosquito

Knowledge is power when it comes to preventing mosquitoes.

Understanding the four distinct stages of a mosquito’s life cycle means you’ll have a far better chance of keeping those pesky whiners away.

The first three stages of development need water – any type of water anywhere will do. In fact, mosquitoes have been found in mines a kilometre below the earth’s surface, and 4000m above sea level on mountain peaks. Mosquitoes are incredibly diverse and different species have adapted to different conditions: some prefer temporary flood waters, some have evolved to only use artificial containers, others prefer permanent water sources, and some like damp earth.

There are about 3000 species of mosquitoes world-wide, and only a few are carriers of disease. So that’s the good news. The bad news? All species bite.

Blood to feed the eggs

While the high-pitched whine of a male mosquito may be annoying, they’re not the ones doing the biting – only the female mosquito bites. She needs blood to produce eggs. After feasting, she goes on to lay large numbers of eggs directly in, on or near water. Depending on the breed, she may lay them singly or in a ‘raft’ of up to 200 eggs. These eggs can survive periods of dry or cold conditions – the embryos can be dormant for years before the conditions are wet and warm enough. That means some species hatch in a few days, while some take much, much longer.

Hatching into larvae

After a mosquito larva has emerged from its egg, it will live just under the surface of the water, feeding and developing. The larva will have an air tube called a siphon (like a snorkel), allowing it to breathe. As the larvae grow, they go through four ‘instars’ or stages, where they discard and regrow their exterior covering. These larval stages can last anywhere from 4 to 14 days depending on species, temperature and food.

However, even in this early stage, the larvae aren’t defenseless. When in danger, they can wiggle and swim in an ‘s’ motion. This allows them to avoid predators or displacement of water, and return to the surface again afterwards.

Pupa – rest time

A baby mosquito will stay as a pupa for a while – from two days up to a week. This stage is similar to a butterfly’s chrysalis – a period of rest while the comma-shaped pupa morphs into its adult body. The pupa needs air to breathe and water to survive, so it sits at the top of the water. If it senses danger, it will use its little flippers to roll and tumble to deeper in the water.

As it matures, its skin splits along the back, and the adult mosquito emerges to rest on top of the water, to dry and harden its body parts.

Adult suckers are ready to fly

The males develop first and then hang around the breeding site. When a female appears, the males identify her by the sound of her wingbeats, and then they mate – very quickly. This is because adult mosquitoes have a high mortality rate, with up to 30% of the population dying every day. They need to get the job done fast. Males live only six or seven days, and only eat plant nectars. Females can survive for up to five months, looking for blood the whole time. A female finds victims by tracking carbon dioxide as it’s exhaled. Once she has fed, she will fly between 1 and 15 km to lay her eggs.

And so, the cycle begins again.

Each specie is different

The complete cycle differs from one breed to the next. Some take as little as four days, while others can take months. Temperatures affect maturation times, too. For example, the culex tarsalis takes 14 days to go through this cycle at 20°C, but only ten days at 26°C.

While every breed is different, they all required still or stagnant water for the first three stages.