It’s late in the wet summer of ’96, and you already know plenty about mosquitoes. There has been a bumper crop of the little suckers this year.
You wouldn’t be at all surprised if there were one in the room with you right now, drawn to your irresistible chemistry. Perhaps it came into your home hidden in the folds of this newspaper. Or maybe it rode in on your shoulder like a tiny, weightless parrot.
Who cares? A mosquito’s just a mosquito, right? Comes with the territory, especially in August.
But a mosquito is not just a mosquito, no more than a bird is just a bird or a tree is just a tree. In fact, a bird could be a golden eagle, American robin, common snipe or a thousand other things, and a tree could be a shagbark hickory, a Douglas fir or flowering crabapple. Seeing them that way makes the world a lot more interesting.
Similarly, the mosquitoes you’ve swatted this summer could have included Aedes vexans, Culex pipiens and Anopheles quadrimaculatus. Maybe even Uranotaenia sapphirina, in which case you’ve squashed an iridescent blue rarity that is the collector’s item in Lake County’s mosquito world.
Yes, Lake County has a mosquito world. At times there could be as many as 30 species, but we’re going to take a look at 14 of the most common–or soon to be common–ones.
A species, by definition, is a group that can mate only with and reproduce its own kind. As long as we’re straying toward the arcane world of definitions, we probably should cover a few entomological (bug science) basics before taking a look at the various makes and models of our area’s mosquitoes.
Mosquitoes are insects that metamorphose (change form) during their lives. They start as eggs, hatch into plankton-like larvae that live in water. These change into pupae, shrimp-shaped things that do not eat but soon morph again into adult mosquitoes, which are slender, delicate flies about a quarter-inch long.
Male mosquitoes are innocent guys who subsist during their short one- or two-week lives on nothing more threatening to us than fruit juice. It’s the females that suck blood. They need blood in order to supply protein to eggs they create at the rate of 200 or more at a pop.
And they get this blood from birds, forest animals, pets and humans by jabbing us with a pointed proboscis containing two tiny tubes. One tube injects anesthetic and anti-clotting agents (causing the infamous itchy bite and sometimes transmitting disease). The other tube draws blood into the mosquito. She’s a heavy drinker, often taking in twice her weight or more.
Some mosquitoes are tough enough to survive a Lake County winter by hiding in sheltered places such as tree holes or buildings. Others survive as fertilized eggs that hatch in spring.
With this brief background out of the way, we’re ready for an informal “Field Guide to the Mosquitoes of Lake County.”
Floodwater mosquitoes
There are at least seven species in Lake County belonging to this group, known as Aedes mosquitoes. They lay eggs on the ground near water. These may remain dormant for long periods, as they’re activated only when inundated. As a result, when wet weather causes rising water to reach formerly dry areas, numbers of eggs that were waiting for just such a flood will hatch, causing population explosions (as happened earlier this summer).
Incidentally, swarming mosquitoes of this variety can be so severe in the Arctic that they’ve been known to kill large animals such as deer and caribou.
In general, the Aedes species are brownish in color. They have striped abdomens, and these markings may be subtle or somewhat bold. There are bands of color on the legs but no wing spots. The rear ends are rather pointy. Palpi (feelers) are shorter than the proboscis (the snout that also is a hypodermic needle).
There are seven kinds of floodwater mosquitoes in Lake County:
Aedes canadensis, like the robin, is one of our first signs of spring, seen primarily in woodlands. Aedes stimulans, Aedes exrucians and Aedes fitchii are the most abundant spring floodwater mosquitoes, even biting during daylight hours.
Aedes triseriatus breed in water held in tree holes and are mean daytime biters that can carry encephalitis, a serious disease that attacks the human central nervous system.
Aedes trivittatus are identified from other Aedes by their two bold stripes on the upper thorax (the back area between head and wings). They bite by night have also been known to carry encephalitis.
Our very common Aedes vexans will travel a mile for a meal and can lay as many as 500 eggs in a pint of water. They’re most active at dusk and produce several generations a summer.
Quick identification tip: When biting, Aedes mosquitoes assume a hunkered down posture, with head and tail angling toward the skin. Other kinds of mosquitoes, we’ll see, bite while holding their bodies in different positions.
House mosquitoes
In spite of the name, you really don’t want these mosquitoes in your house or anywhere around it. This group, officially known as Culex variety, are the most problem-creating members of an already problematic family.
Culex mosquitoes prefer to breed in unwholesome pools of stagnant water. In fact, they like it best when the water’s contaminated, because their eggs utilize the nutritious byproducts of organic decay and microbial growth.
Preferred breeding sites include old tires, beached boats, ditches, catch basins, rain barrels, garbage cans, neglected bird baths–any place water sits.
These mosquitoes are our areas’s most notorious carriers of the serious St. Louis strain of encephalitis. In certain years, outbreaks of this disease have become significant in late summer and early fall, when standing water grows unpleasant and Culex populations are high.
Lake County Culex mosquitoes are drab and brown, with no obvious wing spots. Body and leg bands are faint or not there at all. Their abdomens come to a very blunt end, giving the appearance of squared-off tails. By contrast, the floodwater Aedes mosquitoes have pointed tails.
There are three kinds of house mosquitoes in Lake County:
Culex pipiens is a common species, and if you see one up close, you might notice whitish, scaly bands on its abdomen. These mosquitoes like to rest during the day in and around houses (thus their name). And at night, they bite. Culex restuans breeds throughout the summer but is noticed mainly in spring and fall. Some experts believe they rarely bite people but are a factor in the spread of encephalitis among birds.
The similar Culex salinarius hang around bogs, ponds and parks. They’re implicated in the deadly outbreak of St. Louis encephalitis that hit Illinois in 1975.
All of our Culex species are worth avoiding. How? Remove the watery birthing grounds they require. Reduce time spent outdoors after dark. Use repellents. Have your community arrange larvicide and adulticide treatments.
Quick identification tip: When biting, Culex mosquitoes hold their bodies parallel to the skin surface. This contrasts with the hunkered posture of the Aedes types and especially with the next mosquito we’ll look at.
Malaria mosquitoes
Don’t let the name scare you. Lake County’s version of this mosquito is not known to carry malaria here. But mosquitoes in this group, known as the Anopheles, have been notorious spreaders of the disease, even in parts of Illinois, as recently as the early part of this century.
Lake County’s one malaria mosquito, Anopheles quadrimaculatus, is a large, brown mosquito that likes to lay eggs in quiet ponds, avoiding stagnant, polluted water. It breeds best in warm weather. Females travel up to a mile to feed at night, and just one can produce 3,000 eggs a season.
Spotted wings are clear field markings. Other commonly seen mosquitoes in our area have no wing spots.
Another sign for the sharp-eyed observer: Anopheles mosquitoes have long palpi, or feelers, about the same length as the proboscis. (Palpi should not be confused with antennae, which are feathery and located higher on the head.) Aedes and Culex have palpi that are much shorter, perhaps only a quarter of the length, when compared with the proboscis. Mention that at your next cocktail party.
Quick identification tip: Anopheles mosquitoes tilt their bodies on an angle to the skin surface on which they’re biting. Noses down, tails in the air. This angle can be steep, ranging from 40 to 90 degrees. Other species hold their bodies roughly parallel to the skin surface.
Asian tigers, speckle-wings and sapphire-colored collectors items
Three area mosquitoes are notable in that they don’t easily fit into the previous, larger categories. And one of them isn’t actually in Lake County–yet.
The Asian tiger mosquito, or Aedes albopictus, is an exotic species that was unintentionally introduced in Southern states during the 1980s. It seems that American truck tires were sent to Asia to be recapped, and when they were returned to us, they harbored stowaway eggs.
The tiger mosquito got a foothold, grew in numbers and began its spread, gradually expanding its range toward us. It was most recently spotted as near as Chicago’s North Side.
In Asia, it’s known to transmit the virus that causes dengue fever, but that’s not expected to be a problem in Illinois. More likely, tiger mosquitoes may carry encephalitis.
Their bold stripes (hence, the name) aid in identification. And they prefer to bite during daylight, making these mosquitoes even easier to spot.
Our speckled-wing mosquito goes by the scientific name Psorophora columbiae. Its egg-laying habits are similar to those in the floodwater group, but this is a pastoral bug, found near farms and feedlots. Still, if water is allowed to accumulate in neighborhoods, speckle-wing could show up, and it’s a mean biter.
Lake County’s “collectors item” is known by entomologists as Uranotaenia sapphirina. As the second part of its unpronounceable name suggests, this is an iridescent blue specimen. It breeds along lakes, in ponds and sometimes in the water that pools in tree holes. Eggs may even be found in potholes on quiet roads. Adults are rather unaggressive and not often seen. They’re the colorful “rare birds” of Lake County mosquitoes.
All those Latin names . . .
All that talk about palpi, proboscises, biting and more Latin names. Why bother to know this stuff? Seen one mosquito, you’ve seen them all. And one is one too many, anyway.
Maybe there’s an answer. As locally grown nature writer Dianne Ackerman (born in Waukegan but working in primitive places such as Antarctica, the Amazon, Texas bat caves and New York City), writes, “. . . There’s a way of beholding nature that is itself a form of prayer . . . a devotion to the keenly observed detail and a sense of sacredness.”
Beholding nature. Devotion to the keenly observed detail. Mosquitoes are part of nature and have been for more than 50 million years, representing one of our planet’s best survival stories. And we’ve merely spent a few minutes keenly observing their details.
Perhaps Ackerman, when using words such as “prayer” and “sacredness,” overstates things a bit. But, well, it’s Sunday.
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Thanks to George Balis, an entomologist with Clarke Environmental Mosquito Management Inc., for expert guidance in preparing the facts used in this article.
CALLING IN THE SWAT TEAM
Because mosquitoes are annoying biters and may even transmit disease, Lake County officials work to eradicate them or at least reduce their numbers.
Parts of the county are under the protection of mosquito abatement districts, units of local government with taxing authority, run by volunteers appointed by the county. Their mission is to measure the extent of mosquito problems and arrange relief.
In southeastern Lake County, communities including Highwood, Highland Park, Deerfield, Bannockburn, Del Mar Woods and Riverwoods are within the Southlake Mosquito Abatement District. Farther north, the Lake Bluff Mosquito Abatement District provides similar services in its area. And throughout the rest of the county, individual municipalities and neighborhood associations make their own mosquito-abatement arrangements.
Southlake and Lake Bluff Mosquito Abatement Districts, as well as the majority of communities that independently contract for mosquito control, turn to Clarke Environmental Mosquito Management Inc., based in Roselle.
This 50-year-old company is the largest independently owned firm in the industry and the only one doing integrated mosquito control by land and air or land only in northeastern Illinois.
It’s an entomological “swat team,” using high-tech methods to analyze the extent of infestation, predict mosquito population trends, identify mosquito numbers and types, test for mosquito-borne diseases and effectively kill larvae and adult mosquitoes.
