Warmer Iowa winter brings out the wasps

An unwelcome buzz — wasps — may be more commonly heard this spring in Iowa.

Anecdotally, there seem to be more wasps than usual hovering about following a somewhat mild winter in Iowa, according to weather experts. Iowa State University professor of entomology Donald Lewis said he, too, has heard from Iowans who feel there are more of the insects than usual this season. He also suspects it was a “good winter” for them.

Gabrielle Smithman, a teacher at Merrill Middle School in Des Moines, experienced one effect of that good winter. Smithman closed classroom windows this spring.

The teachers at Merrill move from room to room, rather than having students rotate classrooms, to avoid crowded hallways during the pandemic.

During a warm spell earlier this spring, Smithman noticed a wasp on the inside screen of a classroom window. She quickly shut the window and stuck a Post-it on it, warning the teachers who would follow her.

“I knew if I just left it closed with no note, the next teacher that comes in is going to see a closed window, is going to open it and is going to unleash a wasp into the sixth-grade classroom, and there is no recovering from a wasp inside a classroom. The moment it gets in there, the whole class is derailed. You can pretty much kiss any learning goodbye for that class period,” Smithman said.

The following week she closed three windows in one day because of wasps.

“It’s such a big problem — our principals sends us a weekly little update, and she signed her emails, ‘Yours in catching the wasps.’” Students thee avoid some infested areas at recess as well.

Lewis, the entomologist, said there is no way to officially track the number of wasps from year to year. The state has comprehensive trap data on mosquitoes via the Iowa Mosquito Surveillance Program, said Lewis, who specializes in insects found in and around the home. No similar program exists for wasps because they don’t carry disease like mosquitoes can.

“Those queens hibernate in brush piles, under debris, under the loose bark of dead trees. They get into a protected location, and they make it through the winter,” Lewis said.

Average temperatures recorded last winter in Des Moines were several degrees above normal for all but one month from November through March, according to the National Weather Service. In the other month, February, a prolonged freeze (when the temperature didn’t rise above zero for almost three days) helped pull the monthly average to 11 degrees below normal.

Brad Janssen, co-owner of Janssen Pest Solutions in Des Moines, said his business has experienced an uptick in calls about wasps — not just this year, but in 2020 as well. He estimated that calls increased by more than 25 percent.

The pandemic could be partially responsible for the increase, Janssen said.

“With the era of COVID, I think that just more people are at home, observing, because not everybody is going to the office,” Janssen said.

Janssen said that during this time of year, with temperatures fluctuating, wasps are attracted to the eaves of homes and sunbathed spots on playground equipment because they’re seeking warmth.

Emily Beeman, a Des Moines resident who works as a bus driver for the Waukee Community School District, said wasps this spring are “all over the place.”

While house-sitting on the south side of Des Moines, Beeman had what she described as a “full, dramatic Tolkien-level epic battle” against a wasp that gained entrance through a window in the kitchen. Beeman won.

“But then the next day there was one in the exact same spot. At first, I thought he came back from the dead. But no, it was another one.”

Understanding the life cycle of wasps can help make sense of what Iowans are observing this spring, said Lewis. The wasps Iowans are seeing this time of year are queens, whose job it is to find a location for a nest and build it — but they’re not typically aggressive, he said.

Iowans might think they’re seeing hornets, but that is unlikely, he said.

Lewis doesn’t have good news. There isn’t much to do besides removing nests or spraying them with an aerosol, preferably at night. There isn’t evidence that tactics like making fake wasp nests of small paper bags actually work, Lewis said.

“My guess is that probably works for one person one time, but it’s not going to work for everybody every time,” he said.

He said Iowans should try to avoid floral scents — “less perfume, less aftershave, less floral-smelling soaps during these times, if you’re going to be outdoors, might reduce the attraction. Otherwise, watch out and try to stay clear.”

The best tactic is to leave wasps alone whenever possible.

“You don’t have to go swinging after them. You don’t have to swat them. You can step away and let them go by,” Lewis said.

Meanwhile, Smithman and her colleagues at Merrill Middle School remain vigilant and keep a sense of humor.

“I joked with my co-workers, I felt like it was the ‘Walking Dead’ because they put a note on the very first episode of that — ‘Don’t open, Dead inside.’ I’m like, yep, that’s how it feels with the wasps.”

Nicole Grundmeier is a freelance reporter and writer for IowaWatch. This story was produced by the Iowa Center for Public Affairs Journalism-IowaWatch, a nonprofit, news website that collaborates with news organizations to produce explanatory and investigative reporting. Read more at IowaWatch.org.