Frigid winter not deadly enough for summer's pests

Published: Feb. 1, 2019 at 5:44 PM CST
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We were constantly warned about the dangerous, even deadly, effects of the cold weather this week, so you may start wondering if that spells good news this summer when it comes to mosquitoes and other pesky insects.

"With insects, it's all about whether they freeze or not. If the insect freezes, it's pretty much over," Michael Draney, an entomologist at U.W.-Green Bay, said.

But unlike us, Draney adds, inspects produce antifreeze in their blood to lower their freezing level. They also seek sheltered locations to hibernate.

He says temperatures below zero are often fatal for insects like mosquitoes, but, "They make up for being vulnerable by having a high reproductive capacity. So, if a few of them survive and it's a really good year in the spring or summer, they're going to be able to reproduce and make up for that."

"Many species are able to make up for that very rapidly," he continued, "and mosquitoes are a good example of that. They can go through several generations in a summer and we could have a bad mosquito season here even with this weather."

As for ticks, Draney says, unfortunately for us, they are very hardy.

"They are probably going to be fine, but if you have a long winter, it delays when they come out and start feeding, and that can be very important for us. So I guess for ticks, it's more about a long winter than a hard cold snap."

Better news pertains to the emerald ash borer, whose larvae spend winters in the bark of ash trees.

"If it gets down to minus-20, maybe 80 percent of them might do. If it gets down to minus-40, most of them would die," he said, "and that would certainly mean the trees are going to be able to survive longer and slow down their spread."

Draney adds that, again, unlike us, wind chill doesn't affect insects. That's because they don't produce heat their bodies try to keep in. Their body temperature is in equilibrium with their environment.