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Posted at 11:00 AM ET, 08/25/2010

Eaten by Aedes: The buzz on summer mosquitoes

By Ann Posegate

Wx (Weather) and the City

* Sunshine returns: Full Forecast | NatCast | Hurricane Tracking *

Mosquito Larvae_SDcounty.ca.jpg
An underwater army of Culex larvae, courtesy of Wikimedia Commons.

They lie waiting in storm drains, breeding hoards of underground armies that target unsuspecting pedestrians. They crouch camouflaged in the base of flower pots, their eggs resurrected by puddles from recent storms. They explode from swollen creeks, tracking down their next blood meal with specialized heat-seeking sensors.

Let's face it. Mosquitoes in the DC area have been voracious this summer. Their prolific populations have left us grabbing for the nearest can of DEET. Is it the heat? Severe thunderstorms? Drought? How have we coped ...or have we?

Scientists have identified more than 3,500 species of mosquito around the world ... not a comforting fact for mosquito magnets like me. They are vectors for diseases such as Yellow Fever, Dengue, Malaria and West Nile virus. Virtually no one in the world can avoid these pesky suckers, except those who spend time in Antarctica (take it from me), parts of Greenland, the open ocean or tall mountaintops.

Two hundred of these species are found in the United States. About 60 species of mosquito have been identified in Maryland, and about 57 have been identified in Virginia.

Keep reading to learn more about mosquitoes in our area, how the weather impacts them and what you can do to control them ...

The eastern and southern U.S. also have the pleasure of hosting the Asian tiger mosquito (Aedes albopictus), one of the most invasive species in the world. It was first found in the U.S. in the mid-1980s and has quickly spread by breeding in pools of rainwater that collect in tires stored outside, as well as other wet nooks and crannies in forests and cities.

Whereas other mosquitoes are crepuscular -- most active at dawn and dusk -- the Asian tiger mosquito can and will bite during the day. Despite being a tropical species, it is well adapted to cold conditions: it hibernates over winter; its eggs tolerate cold; and adults can survive sub-freezing temperatures and snow.

Mosquito life cycle_EPA_Leon County Mosq Control_Tallahassee FL.jpg
Mosquito life cycle, courtesy of Leon County Mosquito Control, Tallahassee, Florida.

Mosquitoes need standing water to breed. Lucky us: we've been inundated with strong thunderstorms, floods and plenty of standing water this month. After females feed on blood (males do not bite), they lay their eggs in streams and pools of rainwater in any catchment devices available -- flower pots, depressions in the sidewalk, storm drains, bird baths and supposedly even footprints in the mud. The eggs hatch into larvae, which remain underwater and grow into pupae. The pupae transform into adults that emerge from the water ready to feed.

Although it seems contrary, drought can exacerbate mosquito breeding. There may be fewer pools of rainwater filling flower pots during drought and dry weather, but there are more pools of standing water left in storm drains that would normally be flushed out after storms.

Temperatures can activate viruses within mosquitoes. West Nile virus and St. Louis Encephalitis develop inside their hosts once the temperature reaches about 58 degrees Fahrenheit. The rate of development then doubles for each additional 12 degree temperature increase.

Given the trouble mosquitoes cause to humans and other animals, scientists have been asking: does the world really need them? Some say yes; others disagree. Mosquitoes are an important food source for birds, bats, spiders, lizards, frogs, fish and other insects. Adult mosquitoes feed on flower nectar (females also need blood), and thus serve as pollinators for certain plants.

I guess we can't complain. After all, we do live on a former marsh. Just be thankful we don't live in the Arctic tundra where, when faced with a short breeding season, mosquitoes consume up to 300 milliliters (1.3 cups) of blood per day from a single caribou and form swarms thick enough to suffocate the animals.

With the recent design of the first malaria-proof mosquito, global eradication of the insects may not be necessary, at least as far as humans are concerned.

Tips for mosquito control

Birds and bats are natural insecticides: a small brown bat can devour up to 600 mosquitoes in an hour. Some residents resort to installing bird and bat houses on their properties (learn how to build a bird house and bat box).

Even the small amount of water found in a flower pot saucer is sufficient for mosquitoes to lay eggs in. Remove water from rain gutters, plastic buckets, children's toys, potted plant trays and other containers after a storm. If you have water features such as bird baths or wading pools in your yard, empty and change the water at least once per week. Protect yourself and your family by using insect repellent and wearing long sleeves and pants when outdoors during dawn and dusk.

Tips courtesy of Earth Gauge.

Other resources:
Using DEET safely

EPA Insect Repellent Calculator

Storms likely to lead to bumper crop of mosquitoes (WTOP News)

Screw the Heat, Mosquitos are Coming! (Prince of Petworth blog)

District Department of Health: Summer warning about mosquitoes

Maryland mosquito control program

Virginia Department of Health: Frequently asked questions about mosquitoes

Tips after you have been bitten

Map of West Nile virus in the U.S. from 1999 - 2004

By Ann Posegate  | August 25, 2010; 11:00 AM ET
Categories:  Nature, Posegate, Wx and the City  
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Comments

DC was not built on a swamp. It's a myth that won't die. http://www.welovedc.com/2009/07/07/dc-mythbusting-built-on-a-swamp/

Posted by: Langway4Eva | August 25, 2010 11:44 AM | Report abuse

I was just discussing with someone why there hadn't been many mosquitos around given all the rain we've had. We chalked it up to drought-like conditions earlier in the year and figured that must have been their peak breading time.

But now you say there have been a lot of mosquitos? I haven't seen many.

Posted by: cassander | August 25, 2010 11:55 AM | Report abuse

Oh I HATE them!
But the 25% DEET bug repellents seem to work.
The invasive tiger kind is the worst.....they seem impervious to sunshine & can be very aggressive.
It takes all the fun though of just popping out to the garden for a couple minutes.

Posted by: FIREDRAGON47 | August 25, 2010 12:20 PM | Report abuse

Yeah, I haven't really noticed a particularly bad mosquito situation this year. I wouldn't call it "voracious," that's for sure.

Posted by: SWester2010 | August 25, 2010 1:03 PM | Report abuse

Nice article... sorry to hear you're a mosquito magnet. I think it's interesting that mosquitoes seem to prefer certain people. My brother, for instance, seems to get bit a lot more than I do even when we're at the same location.

BTW, the bat and bird box links need to be fixed.

Posted by: spgass1 | August 25, 2010 1:07 PM | Report abuse

Cassander, you haven't been in my neighborhood. The Asiatic tiger mosquitoes are fierce around here...lots of drainpipes for them to breed in.

Wonder what it was like in the Carboniferous...there was more oxygen in the air back then and the dragonflies were the size of hawks. They must have had mosquitoes ranging in size from bumblebee-sized to tennis-ball sized for food. It's possible this continued into the Mesozoic, when the mosquitoes had plenty of juicy dinosaurs to snack on, though the dragonflies were back to a more normal size by then. Perhaps the reason for the dinos' long tails was so they could swat at the annoying clouds of mosquitoes continually pestering them. The rationale behind Jurassic Park is the possibility that viable dinosaur DNA may still be in the bellies of mosquitoes entombed in Jurassic [and more likely Cretaceous] amber. It's believed that the world's oldest amber dates to the Jurassic, though Cretaceous and more recent Tertiary ambers are more common.

Posted by: Bombo47jea | August 25, 2010 1:08 PM | Report abuse

When I grew up in Florida, we used to have "mosquito trucks" going around the neighborhood spraying like crazy to kill off the mosquitoes. I suspect a lot of people who lived during that era can trace respiratory problems to the spraying (he says as he reaches for his ProAir inhaler).

Anyway, where I now live the water runs downhill, so we've seen some toadstools but no skeeters.

Posted by: JerryFloyd1 | August 25, 2010 1:13 PM | Report abuse

We have had great success this summer using a product called Mosquito Deleter - not affiliated with the company in any way, other than being a happy customer. The product essentially attracts mosquitoes to a small bucket that allows them to deposit eggs, but when the larvae move to the flying stage, they are trapped inside the device. It is amazingly effective - not that we haven't had some mosquitoes, but far less than others in our neighborhood and far less than in previous years.

Posted by: SBrun | August 25, 2010 1:30 PM | Report abuse

They started out mild earlier this summer but in the last month, they have exploded. My arms look like a braille dictionary with all the dots! The worst is when you have one in your home and you don't know it until you have mysterious itching followed by raised, itchy bumps ...then you go on the warpath.

Posted by: authorofpoetry | August 25, 2010 1:38 PM | Report abuse

The idea that DC was built on a marsh is overstated and predicated on a categorical confusion about DC being a swamp of politics. For the most part, DC was built on beautiful rolling farm lands.

Bugs, for their part, were far more identified with the Bay...

Posted by: ecomst1 | August 25, 2010 1:40 PM | Report abuse

The mosquitoes have been horrible!!! I step outside and within 1 minute I am bitten multiple itchy times unless I've soaked myself with DEET (which I don't like to do). They swarm around my dogs, not deterred by the hair. They've gotten into the house too...surprised I haven't gotten West Nile since I've been bitten so much this summer.

Posted by: Susannah3 | August 25, 2010 1:48 PM | Report abuse

Langway4Eva - Thanks for that link, and for busting the myth. 'Floodplain' might be more appropriate. Still, I believe that some parts of the metro area were once tidal wetlands of some sort (before they were farmlands), given our proximity to rivera.

spgass1 - Thanks. Links fixed.

Interesting to hear all of the different perspectives around the region. Mosquitoes in my area of NW DC were really bad in July, then there was a lull for a couple of weeks before they came back strong again. For some reason, mosquitoes also seem to be getting indoors more this year.

Posted by: Ann-CapitalWeatherGang | August 25, 2010 3:49 PM | Report abuse

I used to be a real mosquito magnet. Fortunately, as I've gotten older, mosquitos seem to find me less apetizing.

However...

One of the more persistent "green" suggestions is a rain barrel to collect rain for garden irrigation and other outside uses. Am I the only one who thinks "mosquito breeding tank"? And who refuses to have one around?

Posted by: rlguenther | August 25, 2010 4:35 PM | Report abuse

rlguenther - I think that used to be the case. But there are now barrels with ultra-fine mesh screening that does not allow mosquitoes to get in or out. Check out Aquabarrel in Gaithersburg.

Posted by: Ann-CapitalWeatherGang | August 25, 2010 5:40 PM | Report abuse

My experience so far this summer is that the mosquitos haven't been as bad as normal, but in the past week or so I've begun to notice them.

Posted by: Sarpedon | August 25, 2010 6:46 PM | Report abuse

I recall a news story a couple of years ago that about 20% of the overall population get about 80% of the mosquito bites due to something in their metabolism. I think I'm one of them.

Don Lipman, Capital Weather Gang

Posted by: Weatherguy | August 25, 2010 11:32 PM | Report abuse

The comments to this entry are closed.

 
 
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