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Mosquito of the Month: Culex erraticus

Posted by The VDCI Team on Dec 14, 2016 1:04:57 PM

Written By Courtney Brown, Surveillance Technician

Continuing the theme of mosquitoes of diminutive stature, this month we focus on another small mosquito – the tiny and mighty Culex erraticus.

Culex_erraticus-Carpenter-and-Lacassee_1955_250.jpgIn contrast to the beautiful, benign Uranotaenia lowii of last month, Culex erraticus is dressed more plainly in rich chocolate brown from proboscis to toe with lighter tan banding on the abdomen. Their size is not to be underestimated; they come equipped with a long proboscis with the business end being swollen. Their bite is regarded as painful, with the added insult of being accompanied by a vector-borne disease at times. Even though sorting through great masses of tiny brown mosquitoes quickly becomes monotonous, these tiny mosquitoes are of great interest to mosquito management programs due to their appetite for birds, large hooved mammals, reptiles, amphibians, and humans.

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Topics: Mosquito of the Month Series, Integrated Mosquito Management (IMM)

Mosquito of the Month: Uranotaenia lowii - the Pale-Footed Uranotaenia

Posted by The VDCI Team on Nov 17, 2016 1:06:03 PM

Written By Theodore Heron, Surveillance Technician

Beauty can be found in the smallest of things. Last month we focused on the largest mosquito, or “elephant mosquito,” Toxrhynchites rutilus. However this month, we are at the opposite end of the spectrum with the smallest mosquito —Uranotaenia lowii, also known as the pale-footed Uranotaenia.

http://cdn2.hubspot.net/hubfs/581508/Uranotaenia%20lowii_University-of-Florida.jpgMuch like its overly-sized relative, the pale-footed Uranotaenia has no interest in humans. This lack of interest, combined with its small size, leaves the species often unnoticed in mosquito management and surveillance programs. While the mosquitoes ignore humans, other living creatures aren’t as fortunate. The tiny mosquitoes get their blood-meals from reptiles and amphibians—mostly frogs. Throughout the world, amphibian populations are drastically declining, and many scientists believe habitat destruction and climate change are the primary culprits. Very little is known about how mosquitoes affect non-human species. So, this is entirely speculation, but vector-borne disease may be an additional contributor to this decline. Uranotaenia lowii resides within several pockets of the Western Hemisphere, including the U.S. Gulf states from Texas to Florida, and along the Atlantic seaboard, as far north as North Carolina.

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Topics: Mosquito of the Month Series

Mosquito of the Month: Toxorhynchites rutilus - the Elephant Mosquito

Posted by The VDCI Team on Oct 13, 2016 12:28:42 PM

Written By Michael “Doc” Weissmann, Ph.D., Chief Entomologist

“Massive” and “giant” are not terms most of our partners want to hear associated with insects, especially mosquitoes, in their community. Toxorhynchites rutilus is the largest mosquito in the USA. An adult female can have a wing span of nearly ½ inch, and if it sat on a quarter, the tips of their long legs could dangle off the edges. Yeah, I’d call that massive.

Toxorhynchites_rutilus_septentrionalis_DallasTX_JasonWilliams250.jpgBut fear not – these giant, day-flying mosquitoes do not need a blood meal to produce eggs, so they do not bite. Due to their lack of interest in taking a nibble, they are only caught in certain kinds of traps associated with mosquito surveillance, and cause little concern in the field of mosquito control. Both adult males and females feed exclusively on sugary substances – primarily flower nectar but also plant sap, honeydew, and juices from rotting fruit. They are sometimes called “elephant mosquitoes” due to their long, trunk-like proboscis that curves downward and is pointed at the tip to assist in sucking nectar from deep flowers. Since they don’t bite, they also don’t transmit any vector-borne diseases. Whew!

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Topics: Mosquito of the Month Series

Mosquito of the Month: Aedes aegypti - the Yellow Fever Mosquito

Posted by The VDCI Team on Sep 15, 2016 9:30:03 AM

Written By Michael “Doc” Weissmann, Ph.D., Chief Entomologist

“Celebrity status” isn’t generally something bestowed upon an insect. And yet one mosquito, Aedes aegypti, has been a part of the Zika headlines almost daily for much of the last year, garnering nearly as much attention from the press as the presidential candidates during this election year.

http://cdn2.hubspot.net/hubfs/581508/Aedes_aegypti_250x250.jpgNo other mosquito species has had such a dramatic impact on human history. Also known as the Yellow Fever Mosquito, Aedes aegypti was the first mosquito implicated as a vector of human disease. Experiments in the 1880’s by Cuban physician, Carlos Finlay, demonstrated that when one of these mosquitoes took a blood meal from a patient with Yellow Fever, it could transmit the disease to a healthy person just a couple days later during a subsequent bite. Initially, few people – including members of the scientific community – took the idea seriously, finding it hard to believe that such a small insect could kill a full grown person. It took a couple of decades and many additional experiments to finally prove Finlay’s theory.

Today, many mosquito species have demonstrated the ability to be competent vectors of a variety of mosquito-borne diseases affecting not only humans but also many other animals. Aedes aegypti not only carries Yellow Fever, but is also a vector of West Nile virus, chikungunya, dengue, and more recently making the news as the primary vector of the Zika virus. While a vaccine exists now to protect us from Yellow Fever, vaccines for the other diseases are still under development and keeping a close eye on the Aedes aegypti species remains a top priority in many Integrated Mosquito Management (IMM) programs.

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Topics: Mosquito of the Month Series

Mosquito of the Month: Anopheles quadrimaculatus - Common Malaria Mosquito

Posted by The VDCI Team on Aug 31, 2016 10:52:51 AM

Written By Michael “Doc” Weissmann, Ph.D., Chief Entomologist

Malaria was eliminated from the United States by 1951. Elimination means it is gone, right? Forever? Well, not exactly.

http://cdn2.hubspot.net/hubfs/581508/Anopheles_quadrimaculatus_p_web.jpgAccording to the Centers for Disease Control and Prevention (CDC), about 1,500 cases of malaria are diagnosed each year in the U.S., predominantly in travelers or immigrants coming from countries where malaria transmission is common, primarily from sub-Saharan Africa and South Asia. Could malaria make a come-back in this country? It is not out of the realm of possibility. The malaria parasite (Plasmodium) that causes the disease symptoms in humans was almost eliminated in North America through targeted mosquito control efforts in the early 1900s that included large-scale mosquito spraying (including the use of DDT), and swamp drainage. However, Anopheles quadrimaculatus – one of the primary carriers of the disease parasite in pre-1950s U.S. – is far from eradicated.

Also known as the Common Malaria Mosquito, Anopheles quadrimaculatus is distributed throughout the eastern United States, often occurring in huge numbers in the southeastern states, especially along the Gulf of Mexico. This fact reinforces the importance of strong surveillance and disease testing programs in areas where the species inhabits. It is not unusual for VDCI’s surveillance traps set in the Mississippi Delta region to collect over 7,000 mosquitoes in one night, of which 99% are likely to be this species.

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Topics: Mosquito of the Month Series

Mosquito of the Month: Culex tarsalis - the Western Encephalitis Mosquito

Posted by The VDCI Team on Jul 28, 2016 2:42:28 PM

Written By Michael “Doc” Weissmann, Ph.D., Chief Entomologist

Culex_tarsalis_p_2Western_Encephalitis_Mosquito_250.jpgCulex tarsalis is one of “…a number of species of which little is known and which are not, as a rule, common or troublesome….” This is how Evelyn Groesbeeck Mitchell described this species in her 1907 book, Mosquito Life. By this time, it was already established that malaria was transmitted by Anopheles mosquito species, and that Aedes aegypti was the vector of Yellow Fever. The link between mosquitoes and some forms of encephalitis was not yet known.

Today, Culex tarsalis is also known as the Western Encephalitis Mosquito. It is a species of concern throughout much of the United States, especially west of the Mississippi River, for its competency when it comes to vectoring several forms of encephalitis. In many areas, this species is the primary vector of Western Equine encephalitis, St. Louis encephalitis, and more recently, West Nile virus. Although usually preferring to seek birds as a blood meal source, they also readily bite other animals, transferring these diseases from the bird reservoir to some mammals, including humans.

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Topics: Mosquito of the Month Series

Mosquito of the Month: Aedes vexans - the Inland Floodwater Mosquito

Posted by The VDCI Team on Jun 30, 2016 11:59:00 AM

Written by Michael “Doc” Weissmann, Ph.D., Chief Entomologist

Aedes_vexans_inland_floodwater_Mosquito_250.jpgCosmopolitan – a species of the world, present in many countries and absent in only a few. No mosquito fits this description better than the Inland Floodwater Mosquito, Aedes vexans. They have been collected on every continent except Antarctica and South America. In most of North America this is the dominant mosquito species, becoming less abundant at higher elevations in the Rocky Mountains and at higher latitudes in Canada, and often outnumbered along the Atlantic coast by the Eastern Saltmarsh Mosquito, Aedes sollicitans.

The name “vexans” is from the Latin word “vexāre” meaning to annoy, torment, or harass. In many parts of the world, this species is a major nuisance, the females biting in the evening, peaking in activity an hour or so after sunset. They are opportunistic feeders, taking blood meals from a variety of animals as available, but apparently preferring larger mammals, including cattle, horses, deer, and humans when present.



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Topics: Mosquito of the Month Series

Mosquito of the Month: The North American Rock Pool Mosquitoes

Posted by The VDCI Team on May 22, 2016 4:23:13 PM
Written By Michael “Doc” Weissmann, Ph.D., Chief Entomologist
 
April showers bring…mosquitoes?
 
rock_pool_photo_Castle_Rock_CO.jpgYes, all that spring rain that makes our gardens bloom with May flowers also supplies the water necessary to hatch the first round of this season’s mosquito eggs that have been dormant over the winter. While we tend to think of mosquito larvae as swamp insects, some occur in much smaller pools, created by springtime rains and stream overflows on rocky surfaces.
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Topics: Mosquito of the Month Series

Mosquito of the Month: Aedes sollicitans – the Eastern Saltmarsh Mosquito

Posted by The VDCI Team on Apr 27, 2016 2:00:00 PM
Written By Michael “Doc” Weissmann, Ph.D., Chief Entomologist
 
Mosquitoes carry diseases that can kill people. We know that now. We didn’t always.

Aedes_sollicitans_Eastern_Saltmarsh_Mosquito.jpgToday, many mosquito control programs focus on reducing mosquito abundance because some species can vector life-threatening diseases. However, before making the connection between mosquitoes and disease, it was the nuisance biting that caught everyone’s attention. The Eastern Saltmarsh Mosquito, Aedes sollicitans, was one of the first mosquitoes implicated in creating unbearable living conditions due to their nuisance biting, and one of the first species targeted in large-scale mosquito management programs.
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Topics: Public Education, Mosquito of the Month Series

Mosquito of the Month: Aedes pullatus - the Alpine Snowmelt Mosquito

Posted by The VDCI Team on Mar 30, 2016 12:07:48 PM
Written By Michael “Doc” Weissmann, Ph.D., Chief Entomologist
 
Aedes_pullatus_from_Carpenter__LaCasse_1955-2.jpgHigh in the Rocky Mountains, under the snow and ice, eggs that were laid by mosquitoes last summer lay dormant, waiting for spring. As soon as the ice becomes liquid, the first of the eggs will hatch. 

Known as the snowmelt mosquitoes, these species have a short season in which to grow. In order to get a head start, the larvae are adapted to survive in very cold water, including snowmelt ponds and overflow pools from frigid mountain streams. The cold water slows down their metabolism as well as their development into a flying, biting adult mosquito, which can take several weeks.

One of the most widespread, and arguably most beautiful of these cold-adapted species, is the Alpine Snowmelt Mosquito, Aedes pullatus. This mosquito is often abundant throughout the summer in mountainous areas of western North America, Europe, and Asia. They occur mainly in higher elevations, although also found less commonly as low as sea level in the colder northern latitudes.
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Topics: Mosquito of the Month Series