Wet spring brings mosquito boom

ESCANABA – An extremely snowy winter that led to a wet spring has created a boom in the mosquito population. Run-off from melting snow created a perfect hatching environment for spring floodwater mosquitoes, according to officials.

According to the Michigan Mosquito Control Association, the eggs of mosquitoes that hatch in the spring are found in the leaf litter at the bottom of depressions in the ground that are dry at other times of the year. The eggs hatch once water is present and conditions are right. They are viable for up to seven years after being laid, allowing the species to thrive even after multiple dry seasons.

Mosquitoes may appreciate the Upper Peninsula’s wet spring, but people are less than thrilled about the increase in buzzing blood-suckers. Many stores are finding it difficult to keep bug spray on the shelves.

“We had over 40 cases in on Saturday, but it was gone by afternoon,” said Escanaba Menards Assistant Manager Scott Thill, adding the store was getting more bug spray in all the time.

Because 30 different species of mosquito call Michigan home and different species have different life cycles, the extremely buggy spring may not be an indicator of what the mosquito population will look like in the next few months.

“As we get into the summer months that population will die off and be replaced with a different species of mosquito,” said Bob Heyd, entomologist and forest health specialist for the Department of Natural Resource’s Marquette office.

Unlike the spring mosquitoes – which are long-lived and may bite several times but only have one generation per year – summer floodwater mosquito larvae develop in seven to 10 days. Multiple generations of these mosquitoes can hatch in a summer, but the severity of a summer mosquito season is difficult to predict because hatchings depend on rainfall.

While many may view the blood-thirsty insects as merely a nuisance, the small insects can carry a big – and possibly deadly – punch. Historically malaria and yellow fever are notable diseases carried by mosquitoes, but West Nile virus, other forms of swelling of the brain known as encephalitis, and dengue hemorrhagic fever that are transmitted by mosquitoes have also been documented in the United States.

However, because not all species of mosquito are capable of carrying the same diseases, some diseases are only spread at certain times of the year or in certain regions.

“West Nile Virus is actually (carried in) a mosquito species that hatches mid summer,” said Heyd.

Another animal that has had a particularly notable year so far are bats, which have been hit by white-nose syndrome. The syndrome has been confirmed in bats in Dickinson and Mackinac counties and can lead to large population die offs. While the effects to bats can be drastic, Heyd does not believe that WNS will impact the mosquito population.

“Even though (bats) do eat mosquitos they aren’t one of the major things that controls the population,” said Heyd, adding that roughly 10 percent of a bat’s diet is made up of mosquitoes.