While we humans patiently, or maybe not so patiently, wait for spring, so do the bugs. This includes ones that can carry harmful diseases.
There are a lot of different factors that can help mosquito populations boom in any given year.
Susan Paskewitz is a professor in the Department of Entomology at UW-Madison. She says after two years of low mosquito populations, we’re likely to see more this summer.
The rain outlook is the biggest factor.
“Many of our most important nuisance species, not necessarily the ones that transmit disease, but certainly the ones that we notice in our backyards biting us are very tightly associated with rainfall patterns,” said Paskewitz. “We’ve had a couple of years where we’ve had really low mosquito populations. It’s been quite interesting to follow. Probably because the springs have been a bit dry. Not necessarily anticipating we’ll be so lucky this year.”
While mosquitoes are mostly annoying to humans, they can also transmit disease.
West Nile Virus is one Paskewitz of particular concern, though if we do end up having a wet spring it might not be as concerning.
“Those mosquitoes behave really counter-intuitively. They tend to be more abundant in the dry years. We do worry about that as a potential impact on Wisconsinites when we have those dry, droughty kind of years.”
Severe cases of West Nile Virus and other mosquito-transmitted illnesses are relatively rare in Wisconsin.
The state is home to at least 56 species of mosquitoes.
Ticks
The number of reported Lyme Disease cases in Wisconsin has more than doubled in the last 15 years.
The western upper peninsula has also seen increases in the disease in recent years.
Knowing how abundant tick populations are going to be each season is hard to predict.
Unlike some pests like mosquitoes, the weather doesn’t seem to have as big of an impact on populations.
Paskewitz says one of their best indicators is the wildlife populations the ticks feed off of like white-footed mice.
“When those populations are high usually lot of the immature stages get fed and then the following year we anticipate a larger population of these pests. We think that maybe this year is one of those years where there will be a lot of mice out there just because there were lots of acorns last year so it could mean next year could be our boom year,” she said.
Paskewitz says sometimes people mistakenly think there’s a large tick population in a year because they’re finding the larger, adult ticks on them after being in the woods.
But she says it’s actually the smaller, immature ticks that pose a greater risk.
“The nymphal stage cause they’re so small, those are the ones that are really abundant during June and that we think people often miss them, don’t realize they’ve been bitten. That correlates really well with when we see people get sick,” said Paskewitz.
This year had the earliest occurrence of a nymphal deer tick that’s ever been recorded in Wisconsin, according to Paskewitz.
She recommends taking precautions like wearing long pants and shirts and spraying your clothes with repellant to prevent tick bites.
