Mosquitoes bring to mind undesirable connotations. More than the average bug, they are particularly irritating in demeanor. Their ringing wings announce their arrival and remind you that you should spread out the nets before you lie and unleash your arsenal of insecticides. It helps to know your mosquitoes by species as they herald the threat of different diseases. Let’s take a look at one genus of this insect, the culex mosquito, which is a vector of a number of human pathogens.
Identifying a Culex Mosquito
First of all, Culex mosquitoes are medium sized, which means they will be high pitched in flight and quite fast when moving around your room. They can be identified by the cross veins on their wings and straight abdomen when not full of someone’s blood. Their appearance is a grayish brown and their structure differs from anopheles mosquitoes, which have a pointed abdomen. They also do not have prespiracular or postspiracular setae.
Outdoors, Culex mosquitoes flock together, though they are mostly found in enclosures. This has led to the Culex genus being referred to as the house mosquito as it prefers rooms, caves and outbuildings. Their small body size makes them tolerant to cooler seasons. The taxom, Culex, is latin for gnat which alludes to their appearance.
How do Culex Mosquitoes Develop?
Culex mosquitoes like other mosquitoes are hatched in the water into larvae that feed on vegetable matter, fungi and bacteria. A mosquito can lay up to 350 eggs on a single raft and they hatch after 2 days. As if this wasn’t enough, they lay eggs every third night. The water must be still and reasonably foul for the larvae to forage. In the wild, the larvae, or wigglers as they are otherwise known, are eaten by fish that grab them on the water surface. The Culex larvae actually hang from a breathing tube that juts from the water surface. They molt four times as they keep growing larger.
The larvae mature after two weeks and form pupae, which are shaped like a comma. The pupae are commonly referred to as tumblers, and just like a butterflies, they undergo metamorphosis into adults. Actual metamorphosis takes about two to three days. Tumblers are not completely stationary, they will jerk and tumble when disturbed.
The lifecycle is seasonal with certain months having the largest prevalence depending on the region. Culex mosquitoes travel great distances from their breeding grounds. During winter, they find a warmest moist spot and stay in a state of torpor. The lifespan of an adult Culex mosquito is one month for females and 1 week for males. Temperature is very important as the higher it goes the shorter the lifecycle will be.
Pathogenomics of the Culex Mosquito
Culex mosquitoes are associated with malaria, which is a worldwide killer. It may also carry:
- Dengue fever
- Yellow fever
- Lymphatic Filariasis
- Rift valley fever
- Sindbis virus
- West Nile virus and others.
Some of the diseases are transmitted between man and animals, while others are transmitted between humans. Some of the pathogens are worms, others are parasites, while others are viruses. Culex are not the only type of mosquito that spreads malaria as the Anopheles mosquito also spreads it. They are also responsible for the spread of avian malaria in birds. Pets like dogs do suffer from pathogens transmitted by the Culex mosquito.
The vast number of diseases the Culex carries is precisely why mosquito-borne disease research efforts strongly focus on this type of mosquito.