The Common House Mosquito: An Unwanted Companion in Our Lives

Culex pipiens is the common house mosquito—the one that tries to bite you at night and wakes you up with its dreadful buzzing

Culex pipiens is the common house mosquito—the one that tries to bite you at night and wakes you up with its dreadful buzzing. The typical behavioural pattern of this nocturnal pest is to come into our houses and attack us between sunset and sunrise. A single Culex pipiens, eager to get enough blood to lay its eggs, can ruin your night with multiple bites: the female of the species needs this blood meal to complete her biological cycle.

Like those of other mosquito species, the larvae of Culex pipiens are aquatic and can develop anywhere water collects, in any kind of container, gutter or structure. Consequently, mosquitos are found everywhere. Moreover, they can inhabit either clean or polluted waters, even cesspools and poorly maintained sewers.

Curiously, in today’s media-saturated world, we are easily alarmed by the transmission of exotic viruses like Zika but have failed to notice that this mosquito and another of the same genus—Culex perexiguus—have been spreading West Nile virus in Andalusia and nearby regions since at least 2010. In Spain, West Nile virus has been affecting horses since at least 2010 and cases in humans were reported in 2010 and in 2016. Continuous outbreaks throughout Europe—in countries such as Greece, Romania and Italy—have claimed dozens of lives.

Culex species have been responsible for spreading encephalitis, including the Saint Louis and Japanese variants (the latter causes more than 50,000 cases and 10,000 deaths each year)

In various parts of the world, Culex species have been responsible for spreading encephalitis, including the Saint Louis and Japanese variants (the latter causes more than 50,000 cases and 10,000 deaths each year). These mosquitos are also responsible for the spread of West Nile virus, which has affected more than 40,000 people in the United States since it first reached the country in 1999. The common house mosquito also spreads filarial worms—including Dirofilaria immitis, which affects dogs—and several Plasmodium species that cause avian malaria.

Culex pipiens is a very adaptive species. Some of its ecological forms prefer to feed on birds at northern latitudes but are more likely to bite humans at latitudes farther south. The mosquito’s appetite can also vary depending on where the larvae develop. For example, mosquitos that mature in an underground environment where organic matter is present will be more likely to feed on humans than on birds. Because of this plasticity, the common house mosquito can act as a bridge vector, spreading viruses between different animal species—including humans.

Their adult lives are short—rarely more than 15 days

In the summer, over the course of one week, adult mosquitos develop from the eggs laid by the female in raft-like clumps on the surface of the water. Common house mosquitos do not fly very far from where they develop as larvae; at most, they will venture a few dozen metres away. Their adult lives are short—rarely more than 15 days.

Make sure there is no standing water nearby, since these mosquitos will breed anywhere moisture accumulates

What can you do to keep Culex pipiens out of your house? Make sure there is no standing water nearby, since these mosquitos will breed anywhere moisture accumulates. Any jars, water drums, flowerpot saucers and similar recipients should be emptied regularly. Remove all discarded objects that can hold water, such as plastic containers, bottles, toys and glasses. Swimming pools and ponds should be well maintained. The common house mosquito is found in the same habitats as the tiger mosquito and also in drains, where it can be the most abundant species.

To protect yourself, install window screens and use insect repellent. Remember—they bite at night!

To protect yourself, install window screens and use insect repellent. Remember—they bite at night! When applying insect repellent, make sure you follow the instructions. Use a brand that is proven to work, ideally one containing DEET. Two things you should know: ultrasonic insect repellents do not work at all and the efficacy of bracelets and similar devices has not been demonstrated.

In the fight against mosquito-borne diseases, these vectors unfortunately are not monitored as well as they should be. National and international networks are needed in order to improve mosquito-surveillance efforts. To combat these emerging diseases, we need to adopt the same attitude that led to the eradication of malaria in Spain in the mid-20th century.

More information

"Usual Suspects: 006 Culex mosquito" infographic