Category: Science

Anopheles Mosquitoes

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The Anopheles mosquito is just one of hundreds of species of mosquito that can feed on humans and animals and transmit disease. The Anopheles is best known as the most common transmitter of malaria among humans, but it can also transmit several other diseases. And as a pest, it causes itchy bites during the summer months.

Life Cycle and Habitat

Anopheles mosquitoes, like most other mosquito species, lay their eggs in water. The eggs hatch into larvae, which then mature into pupae and adults. The length of time that it takes for the mosquito eggs to mature into adult insects varies based on the outdoor temperature, but it takes at least a week to occur.

Anopheles mosquitoes prefer clean, still water in which to lay their eggs. Roadside ditches and pools that retain rainwater are a favorite site. While Anopheles mosquitoes, and malaria, are typically considered problems of tropical and subtropical regions, Anopheles mosquitoes are actually not very dependent on warm temperatures for survival and have been found as far north as Canada. Larvae of new subspecies have been imported into the United States in water found inside tires shipped from other parts of the world.

Anopheles Mosquitoes and Malaria

Originating in Africa, Anopheles mosquitoes are best known as carriers of Plasmodium falciparum, the microorganism that is known to cause malaria in humans. The malaria microorganism does not cause disease in mosquitoes. The mosquito ingests immature malaria microorganisms when it feeds on blood from an infected human. The malaria organism travels from the mosquito’s mouthparts to its gut, where it matures for up to three weeks before traveling back to the mosquito’s salivary glands. When the mosquito bites another human, malaria is transmitted to that human in the mosquito’s saliva. Anopheles mosquitoes are especially dangerous because they show a preference to feed on humans and birds over other species.

Controlling the Anopheles mosquito population and preventing mosquito bites are critical to preventing malaria, especially in parts of the world where malaria is common and medical attention is hard to come by. It is also becoming important in colder climates like the midwestern United States, where malaria was once eradicated and is now re-emerging due to the introduction of Anopheles species into areas where they were once less common. The use of mosquito nets and mosquito control programs has been very effective in reducing the rates of malaria infection in much of the world.

Other Diseases

In addition to malaria, Anopheles mosquitoes can transmit a variety of other diseases to humans and pets. Anopheles are one of several mosquito species that transmit heartworms to dogs and cats. They also transmit the microfilaria, or microscopic worms, that can cause elephantiasis in humans.

In recent years, other viruses transmitted by the Anopheles, such as O’nyong’nyong fever, have been discovered. It is likely that many of these viruses have co-evolved with mosquito species over time and that more viral diseases may be discovered as research into mosquito life cycles continues.

Controlling Anopheles Mosquitoes

The mainstay of controlling Anopheles mosquitoes is treating or eliminating the fresh water pools in which they lay their eggs. Providing good drainage in ditches and lawns and getting rid of old tires and other debris that retain water after rain are important in good mosquito control programs. Bird baths should be treated or drained. Mosquito baits can be used; these kill mosquito larvae and pupae in water sources before they can hatch into adult insects. Choose baits that are not harmful to pets and wildlife to preserve the environment while controlling mosquitoes.

Anopheles mosquitoes are most active at dusk and during the nighttime hours, and they find their prey (humans) by sensing body heat and carbon dioxide. To protect yourself, try to stay inside or under netting during the evening hours. Make sure window screens are in good condition, and consider using repellents. Repellents can be sprayed on your body or used in the environment in the form of citronella or other repellent candles to keep the bugs at bay. Anopheles mosquitoes are troublesome and spread disease, but by following these simple tips you can protect yourself from being bitten.

 

Lifecycle of a Mosquito

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The life of a mosquito begins in the water and ends in the air. Undergoing a metamorphosis any sci-fi buff would admire, radical transformations must occur in order to change a water insect into one that flies. A mosquito achieves this by developing through four different life stages: egg, larva, pupa, and adult.

Egg Stage

Nearly all mosquito eggs are laid in pools of water. These are stagnant pools with no flowing water to disturb the eggs. If you have a pond,birdbath, or even a long-standing puddle in your yard, you could be harboring a mosquito nursery! The eggs tend to clump together in what is called an “egg raft”, floating along the water’s surface. The length of gestation depends on the species, with some incubating for a few days, while others can survive in egg form all throughout winter until spring comes. Whether they were an egg for a few days or weeks, they will eventually hatch into the next phase of their lifecycle.

Larval Stage

A mosquito larva is essentially nothing but a cylindrical body with a head and mouth. The larva live on the water’s surface where they hatched, breathing through a siphon in their abdomen. They are able to swim away under the surface if they are threatened by predators. They feed on algae and other nutrients found at the water’s surface. As they grow, they shed their skin several times until they are ready to move on toward the next stage in their lifecycle.

Pupal Stage

During the pupa stage, the mosquito does not do much other than grow. The pupa consists of a curled casing inside which an adult mosquito is developing. The pupa does not eat. It only swims to avoid predators and to breathe. A mosquito may stay in the pupal stage anywhere from a few days to weeks. This largely depends on environmental factors such as temperature as well as differences between species.

Adult Stage

At long last, when the conditions are just right, the pupa breaks open and a full grown mosquito slowly emerges. The mosquito’s exoskeleton is soft and its wings are wet at this point, so it rests on the water’s surface until the clear, soft exoskeleton hardens into the dark brown we know so well. The mosquito then finds a place of safety where it slowly opens its wings and allows them to dry. It is now fully transformed from an aquatic larva to a terrestrial and aerial insect.

Mating usually happens soon after emergence into adulthood. Not all mosquitoes are bloodsuckers. Needing the extra nutrients to feed the eggs growing inside of her, it is the female mosquito that goes out in search of a blood meal. Male mosquitoes generally feed on sugary sources of food, like nectar. Female mosquitoes are also attracted to sugary foods and eat them in addition to blood. Females can live for a few weeks, reproducing as much as possible, while males typically die after seven to ten days.

Lifespan

The life cycle of a mosquito from egg to adult depends largely on the environment, with each stage varying drastically depending on several factors. For example, a 10 degree change in temperature from 70 degrees Fahrenheit to 80 degrees Fahrenheit can increase the duration of the developmental stages by four days from 14 to 10. In other cases, some mosquitoes take a full month to develop fully while others in very warm climates may develop in only 4 days. On average, the first 3 stages of development take about 5-14 days to complete. That coupled with the average adult lifespan of 7-14 days gives a total lifespan of a mosquito of 2-4 weeks.

Understanding the lifecycle of a mosquito can help professional mosquito control services eradicate them, and help you avoid them. Now that you’ve armed yourself with knowledge of the enemy, go out and enjoy a bite-free summer!

 

Marking Mosquitoes for Study

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How It’s Done and Why It’s Important

It’s a well-known fact that mosquitoes annoy most people. They are ravenous blood-thirsty insects that bite and feed at will. Much like a classical monster, they live a parasitic existence to ensure their own survival. Mosquitoes are widespread, so much so that at least one species exists on every continent, save for Antarctica. In truth, not all species of mosquito are dangerous, and some actually help us, but most are the blood-drinking terrors that we have grown to avoid.

Pointing Out the Bad Apples

But mosquitoes cannot be simply exterminated en masse. As much as it would please many people to have it happen, they are a necessary part of the ecosystem. To this end, we have developed techniques for marking mosquitoes to study them.

In many cases the mosquito is marked with a capture, release, and recapture program utilizing boxes that are full of fluorescent powder. The mosquitoes find their way into the traps and come out covered in powder that glows various colors. It does not affect their natural role, as animals don’t have access to the same light sources as humans do. But it does offer people looking to study the animal an avenue to do so.

Many places mark mosquitoes every single year and the reasons might be surprising.

Just What is all the Fuss About?

There are a lot of reasons for mosquito marking programs, despite the obvious cost both financially and in intensive labor.

Mosquitoes carry many vector-based illnesses and blood-borne pathogens. As parasites, they spread these illnesses, some of which cross species barriers, to every host they bite. Biting is risky for the mosquito in nature. So when the mosquito gets the opportunity, it drinks as much blood as possible, which the female uses for the development of eggs. When a West Nile virus infected bird is bitten, the mosquito that did the deed has her blood supply infected as well. Each subsequent person she bites is then exposed to the disease.

That is what makes marking mosquitoes so important. In order to track which species of mosquito are infected, they are captured quickly after becoming adults. This is also used to monitor where the new adult mosquitoes go and what they bite. This is essential in creating a mosquito control plan for a given area.

The really difficult thing is finding non-invasive solutions for marking mosquitoes that won’t alter the behaviors of mosquitoes in a significant enough way that the science becomes invalid.

Advances by Stride

Mosquito marking has seen a lot of advancements since its inception. These efforts were to create not only a method to track the lives of these potentially dangerous insects but also to do it in a way that they are still able to live their lives. Mosquitoes are essential to the ecosystems in which they live, both as parasites and as prey for other creatures that make the same areas their homes.

Fluorescent powder is not the only tool used for marking mosquitoes now. Other things have been implemented like special proteins strands that cause the mosquito to be monitored via special lighting. The dayglo powders of the past are long out of use as they have made mosquitoes bigger targets for their prey than is natural, although one of the main ways to control the mosquito population is to increase the population of dragonflies in the area. This science continues to grow.

 

Mosquito Research and Funding

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Mosquito research and funding is an important factor in maintaining the public health of people all around the world. Without funded research, we would not be aware of the many diseases passed to humans and other animals by the insects, which have caused widespread epidemics throughout much of the world. Even in the U.S., where a large amount of mosquito research and funding originates, the instances of West Nile Virus passed to humans by mosquitoes continues to rise, even as the population of mosquitoes falls through control and prevention.

Research

Mosquito-bourne disease research is not one of the most popular scientific areas of study, and is often overtaken in both volume and funding by studies into lesser known diseases. Research into the transmission of viruses by insects to humans and animals is relatively young in its history; the first research into the transmission of Texas cattle fever by ticks took place in 1893, which lead on to further research into tick and mosquito borne disease.

When considering mosquito research and funding, the relatively small amount of money invested by government agencies at state and national levels is quite shocking. For example, the state of Florida in the U.S. has capped its research funding into mosquitoes at around $250,000 since the early 21st century.

Learnings

Each area of the world has its own varieties of mosquitoes. Research has shown a state the size of New Jersey has more than sixty different species of mosquito. When considering how widespread the insects are around the world, the number of different species that have been discovered is breathtaking.

In order to understand the dangers each type poses, it’s important to understand each species behavior. Through continued mosquito research and funding, researchers have developed the knowledge that the culex mosquito is the carrier of the West Nile Virus. Other research has shown which species are linked to other fatal diseases like malaria and yellow fever.

Behavior

Many mosquito studies have been conducted into the breeding patterns and life cycle of the insect. Research has shown the mosquito prefers to breed and lay its eggs in moist areas of the ground and in stagnant pools. Through this, we have developed the knowledge that mosquito populations can be limited by removing standing water.

Attraction

A recent study by Notre Dame University looked into the reasons mosquitoes are attracted to humans and other animals in a bid to help the development of mosquito repellents. This research found the mosquito is attracted to a chemical produced by humans called nonanal. Birds are also producers of nonanal and are the major transporters of mosquitoes around the globe. As only the female mosquito feeds on blood, knowing why the female is attracted to humans is important in developing repellents to protect humans from mosquito bites.

Because of the fact that the majority of the time mosquitoes are feeding on the sugars produced by plants, the future of mosquito research and funding probably lies in understanding why certain flowers attract mosquitoes. By understanding what attracts mosquitoes we can develop better prevention methods and repellents that can protect us from many dangerous diseases.

Why Do Mosquito Bites Itch?

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It is a common misnomer to declare the ceaselessly tiresome red swelling on one’s arm a mosquito “bite.” A mosquito doesn’t so much as bite as pierce the skin and draw blood in a similar vein as a phlebotomist. Furthermore, the primary reason why that itching is so persistent has as much to do with the person as it does the mosquito.

Why Do People Itch?

Recent scientific studies indicate that all itching may be caused by a molecule called natriuretic polypeptide b (Nppb), which is released by the heart and sent to the brain via the spinal column. It is quite likely that without this molecule being sent to the brain one could avoid the itching from the mosquito altogether. Essentially, instead of being angry at the mosquito one could be angry at their own heart, spine or brain.

Why Does the Mosquito Want Your Blood?

It is understandable for one to think a mosquito is sucking your blood like a vampire for greedy sustenance. This isn’t really the case. Male mosquitoes gather nutrients from plant nectar and sugar sources as do the females. However, females require blood for their eggs and reproduction.

A Short Narrative From Proboscis to Fingernail

A female mosquito locates its prey, lands on it, and pierces the flesh with its proboscis. The proboscis is like a long needle, but victims rarely feel the “bite”; they more often feel the reaction. The mosquito finishes drawing blood and flies off, or perhaps is squished in the process. The human response that follows is why mosquito bites itch.

In order to draw blood quickly and effortlessly, the saliva of the mosquito contains an anti-coagulate so the blood flow remains constant. This saliva causes the human immune system to send antibodies to the intruder, which in turn triggers histamine. You may notice that “anti-histamines” are a common term to describe anti-allergy products. It is the histamines that cause blood vessels near the bite to swell up and display a physical queue of where to scratch.

Scratching this area and digging into it with fingernails, poking an X on it and other assorted physical voodoo may work are but temporary victories in the battle against the itch. These “victories” eventually lead to even more itching and pain because the immune system kicks in, yet again, to help by sending in more antibody soldiers and resulting in more heartache. The itching is not first and foremost on the mind of the immune system. The immune system wants the saliva-intruder out by any means necessary.

Developing a Tolerance to Mosquito Bites

Many children and adults get allergy shots to help reduce severe immune response to offending histamines. On a similar principle, the human body may grow more tolerant of mosquito bites over time. Still, it is not recommended that you purchase mosquito saliva and inject yourself with it nor go outside amongst a swarm of hungry mosquitoes in hopes of being “cured.”

Fascinating Conclusion

Blame not the mosquito as much as the person for the bites and subsequent itch.
The more you sweat, breathe and efficiently process cholesterol, the higher the likelihood of attracting mosquitoes. A mosquito also chooses its blood supply by sight. Therefore, preventative measures often include general avoidance of any area where mosquitoes exist.

The itch is an immune response you need if you were to consider what might occur if a swarm of mosquitoes were able to painlessly and itchlessly suck out enough blood for its victim to die. This immune response prevents such an occurrence with the mere cost of an itch. It’s a worthy compromise.

 

Larval vs. Adult Mosquito Control

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There are two different types of mosquito control. You can try to reduce the population of larva or you can try to reduce the population of full grown adults. Each have their own upsides and downsides. Here are the differences in larval mosquito control vs. adult mosquito control. One of these processes should be an option to help reduce the population around your home and keep your family safe.

Mosquito Larva Control

By reducing the population of mosquito larva in an area, subsequently, there should be fewer adults around to bite you. This is called source reduction. There are two main options when it comes to reducing the population of larva: reducing the areas where mosquitoes can breed and lay eggs and introducing predators into their ecosystem.

Area Reduction
Mosquitoes like to breed by damp areas that have standing water. The eggs are laid in stagnant water, the edge of a water source, or on plants that grow in water. By reducing the usable area the mosquitoes have to breed and lay eggs, you will reduce the amount of adult mosquitoes in your area. The thing all these usable areas have in common is the water. By filling in holes that hold stagnant water and killing aquatic plants by pulling them or spraying them with herbicides, the mosquitoes will look elsewhere to lay their eggs. Even by simply picking up trash that may collect rain water, you will reduce the area they have to lay eggs. Without a concentration of eggs and larvae surviving in your area, fewer adult mosquitoes should be around to bother you.

Introducing Predators
Mosquito eggs and larva have natural enemies. If you do not want to remove a water source, you may want to introduce some of these predators. This is called biocontrol. Bass, bluegill, piranhas, salmon, trout, catfish, and goldfish all feed on the larva of mosquitoes. If you add a few of these to your water source, they should devour many of the larvae before they have the chance to grow into adults. Fungi and nematodes can also assist in the reduction of the larva population. As will bacterium-laden mosquito dunks. Place dunks in any body of water you wish to treat, and the bacterium released from the dunks can eliminate larval-stage mosquitoes quickly.

 

Adult Mosquito Control

Many of the effective ways in keeping the larval population to a minimum also work for adults, while others are best reserved for the full-grown variety.  Through the use of biocontrol, insecticides, and exclusion, you should be able to keep your pest problem to a minimum.

Adult Mosquitoes’ Natural Enemies
Source reduction is more effective for the egg and larval stage of the mosquito’s life, while introducing natural enemies can be more effective against adults. You will need to find different natural enemies to defend against the full grown insects. If you have access to a large quantity of dragonflies, this can be an effective tool in reducing the population. Bats and purple martins eat insects, but not just mosquitoes, so their use is still up for debate.

Insecticides
The use of insecticides can be useful in getting rid of these pesky pests. Mosquitoes have evolved, though, and a pesticide that works for some, may not work for all. There are 3,500 species and making one chemical that can deter all mosquitoes is a daunting task. Repellents are often used by applying them to the skin when you are in an area that has many mosquitoes. DEET, picaridin, eucalyptus oil, indalone, dimethyl carbate, IR3535, and ethyl hexanediol are all effective repellents.

Exclusion
Before you have exhausted all of these techniques you should start with one of the simplest ways of keeping the insects away from you. Covering all windows of your home with a screen will help to keep them out of your house and off of your skin. Use a screen with very small holes so they cannot get through. Mosquito nets can be used as well. The best kind of mosquito net to use is one covered in insecticide. This is the most effective way to control mosquitoes in a residential area.

By reading this, you should realize the difference in larval mosquito control vs. adult mosquito control. Hopefully you can find an option that works for you to keep these disease carrying pests away from you and your family.