Monday is game day for mosquito fighters.
Each Monday morning, the Metropolitan Mosquito Control District’s Kirk Johnson and his crew set out traps baited with dishes of stinky water, traps that are as delicious to mosquitoes as a plate of spaghetti carbonara is to a pasta lover.
Each Monday at sunset, Johnson and the rest of the Monday Night Network spring into action again. An early-to-bed/early-to-rise guy, Johnson sets his alarm and wakes to join the 86 others who venture into their backyards or neighboring parks — without wearing Off! — to make themselves into what Johnson calls “attractants” but most of us would call “mosquito bait.”
At a precise time (which varies depending on when the sun goes down), they stand still for a solid minute — luring nearby mosquitoes and essentially shouting to them, “The blood bar is open. Come at me!”
After 60 seconds, the volunteers spend two minutes waving nets to catch the bloodsuckers they have attracted so those samples can be used to determine where mosquitoes are hitting hardest and, thus, where the Mosquito Control crew needs to send in its troops.
“We’ve done work to determine what the level of tolerance is for people living in the metro area,” Johnson said. “That comes in at two mosquitoes in two minutes. If we have a level where we capture more than two in two minutes, that tends to equate to a point where people say they are bothered by mosquitoes.”
A net with two dozen skeeters qualifies as “a pretty intense mosquito population,” he said, but numbers soared as high as 100 this month.
So, if a Monday Night Networker captures two dozen pests, do they feel lucky? No, said Johnson: “They feel like they want to get back in the house.”
Johnson, who has degrees in biology and environmental studies, is a vector ecologist for the Mosquito Control District (“vector” refers to pathogens that are carried about by other creatures). But the ecologist, who was drawn to mosquitoes because of his interest in their hang — wetlands — has come to know a heck of a lot about the pernicious creatures.
After 21 years with the district, he can tell you there are 52 kinds of them in Minnesota, with life spans from a couple of weeks to a few months.
Or that, despite popular wisdom, some species attack during the day.
Or that the reason most mosquitoes strike during cooler hours is because that’s when they require less energy to fly and their victims are less active.
“Kirk is kind of our eyes for the metro,” said Dave Neitzel, supervisor of mosquito and tick-borne diseases for the Minnesota Department of Health (and the creator of the Mosquito Control District’s surveillance and control program). “We know what kind of numbers to expect elsewhere in the state once we know what’s going on in the metro.”
If there’s a mosquito breeding site that needs to be taken care of or another buggy mystery to solve, Neitzel said, he’s glad to know that Johnson and crew are on the case.
‘One unlucky person’
Johnson admits he has a “higher tolerance for dense mosquito populations than a lot of people,” in part because he spent his early years in western and northern Minnesota.
He stops short of calling Twin Citians wusses, but points out that Mosquito Control efforts (by helicopter or by hand) can wipe out 80 to 90 percent of the larvae in a targeted area. Unless they spot a helicopter overhead, most Twin Cities area residents may not even be aware of those efforts because we are so used to having a managed population of Minnesota’s unofficial state bird.
“People who grew up in the Twin Cities don’t realize what it would be like if Mosquito Control didn’t exist,” said the Richfield resident. “It would be like the lake cabin experience here. It would be intolerable, bad enough that it would drive people indoors.”
Speaking of which, Johnson’s family has a cabin Up North, but he doesn’t get up there to be eaten alive by mosquitoes in the summer because he’s too busy trying to control the bug population in the Twin Cities. And getting bitten here.
“I tend to be attractive to mosquito bites,” he said. “It has a lot to do with metabolism. If you’re in a group of people, there’s always that one unlucky person who gets bitten a lot.”
He follows standard recommendations for avoiding mosquitoes: wearing long sleeves and pants and a repellent that contains DEET or picaridin and staying indoors at dusk or dawn, when the bugs are at their buggiest. If he’s doing a riskier activity such as canoeing in northern Minnesota, he’ll don a head net, too.
Johnson jokes that he’s “tight” with mosquitoes, so it’s safe to say his relationship with the pests is more complex than most of ours.
“There are times I despise mosquitoes, sure, but I’m still fascinated by all of the differences among the species and the challenges we go through in our agency, determining how best to control each species,” he said. “The constant changes and the new ways we respond to them keep the job very interesting.”
A treasure hunt
Choosing his top mosquito is tough (“it’s like kids — it’s hard to pick your favorite,” Johnson said), but he’s partial to the contrasty, black-and-white look of the Orthopodomyia signifera. He’s most fascinated by the Aedes triseriatus, whose favorite spot tends to be out-of-the-way water containers, such as discarded tires and unscreened rain barrels.
“You have to find their habitat first,” he said. “You have to investigate wooded areas and other things, even birdbaths. It’s almost like a treasure hunt.”
The success of that hunt depends on the season as well as amounts of heavy rainfall and heat, both of which are associated with aggressive mosquito populations.
“After a widespread rain, we might treat 30,000 acres of wetland by helicopter,” he said. The seven-county metro area has 75,000 wetlands.
“That requires a lot of human time, and it’s all surveillance-driven,” said Johnson, who lists western Hennepin and Carver counties and northern Anoka and Washington counties as hot spots because they have so much surface water.
Other areas of Control District interest are “catch basins,” those drains you see all over the place in the middle of curbs. There are 280,000 of them in the metro area, many with hidden pools of standing water that mosquitoes love, so the district treats about 80,000 of them each month.
And many of the Monday Night Networkers also cover the metro area, distributing 137 traps baited with carbon dioxide and 36 stinky-water, or gravid, traps (“gravid” meaning “pregnant”). Trapped critters are studied in the district’s lab, to determine how to hone the continually changing efforts to control the population.
“The water is a bait made to simulate the wetlands that mosquitoes would want to lay eggs in,” said Johnson, noting that the combo of water, hay, brewer’s yeast and protein powder is not unlike the ingredients of a craft beer, albeit a craft beer with the bouquet of an outhouse.
“The brewer’s yeast metabolizes plant material, so the bait we use mimics a wetland, with rotting grass in it and a lot of microbial activity, which is exactly what mosquitoes look for.”
Mosquito surveillance is conducted by the Control District’s 208 seasonal and 54 full-time employees, who collect samples and apply mosquito larvicide, exposing themselves to the irritating bugs so you don’t have to.
“They take great pride in helping knock down these populations,” Johnson said. “They’re more acutely aware of what the mosquito populations are like in the areas where they work than just about anybody.”
All of us help in that effort every time we slap our own arms to interrupt a mosquito in the midst of a “blood meal,” of course. Every mosquito counts, said Johnson, who notes that the persistent pests are survivors that have been on this planet a lot longer than humans.
Which is why, when it comes to putting the brakes on the mosquito population, he said, “I’ll take any help I can get.”