HOW COME?

Cold truth: Insects don’t die

Now is the winter of our discontent - Richard III

At least it will kill the bugs! - Everybody else

Snow and freezing rain fell in far southeast Arkansas on Feb. 11. It was the 14th occurrence of winter precipitation in Arkansas in this unusually cold, gray winter.

Hey, if we’d wanted this much ice and snow, we’d move to Chicago. That’s what everybody says.

Being human and thus being optimistic, here’s the other thing everybody has been saying:

At least this winter of closed schools and bent fenders and inconvenience will kill the bugs, making the spring and summer gloriously free of insects.

Um, no. Not even close.

“Our climate doesn’t get cold enough to affect the insect population.”

So says John Hopkins. He should know, at least based on his having several mosquito traps and one gypsy moth trap in his office. (Not to worry. There is no impending outbreak of the defoliating moths.)

But don’t take his word for it. Hopkins is only agreeing with Henry W. Robinson and Robert T. Allen, authors of “Only in Arkansas. A Study of the Endemic Plants and Animals of the State.”

In this 1995 work, they tell us the Class Insecta is “the most successful group of organisms inhabiting the earth today.”

Oh, great.

“In Arkansas,” they add, “we estimate that there may be thirty-five [thousand] to forty thousand species. Most of these species are common and occur over a large geographical area.”

Hopkins is an urban entomologist with the University of Arkansas Division of Agriculture in Little Rock. He studies insect problems in urban environments, mainly what affects people rather than crops and other plants.

Insects overwinter in two ways, he says. They go dormant. Or they remain active and figure out a way to stay alive.

Insects that go dormant are susceptible to freezing, but have a couple of ways to cope, Hopkins explains. Some may generate an internal anti-freeze, which they start to produce metabolically when the weather turns cold. Call it a cryo-protectant. A second way to cope is by dehydration, cells with less moisture being less susceptible to freezing. Small insects are better at dehydration.

Easy to think of seed ticks right now, isn’t it?

Bugs do die from the cold, depending on the temperature and the duration of their exposure. But they might have left something behind. Something like eggs.

Eggs, Hopkins said, have, as a general rule, evolved to survive winter. In fact, eggs and pupae are more cold-tolerant than are larva and adults.

Insects also migrant to happier places, like snowbirds leave Minnesota in the fall and head to Florida.

Bugs will migrate from open fields into forests, where they can burrow down into the cover provided by leaves. Or, even better, they will move into a heated building. Smart bugs move from the north side of a tree to the warmer south side.

Even the right kind of snow - a fluffy layer - will insulate insects from the cold.

When spring comes, insect populations go with the flow. After a mild winter, they will begin to increase in the latter part of March. After a normal winter, in April or May. After a cold winter? Later, but inevitably.

All right, then, to the crux of the matter: What would it take to kill sufficient numbers of insects to make life less annoying?

“It would take a relatively long period, maybe three or four weeks of subzero or single-digit temperatures.”

Wow. That would really be cold. That would be Duluth. But it wouldn’t be Arkansas.

John Robinson is a meteorologist at the National Weather Service office in North Little Rock. Asked about such an extended period of cold, he is more than skeptical.

“Virtually impossible,” Robinson says.

Why?

“Because even when we have a cold snap, temperatures don’t go that low or don’t even persist for a week. The cold air doesn’t have that much staying power.”

Maybe there is such a cold snap in the recorded weather history for Arkansas.

Likely not, Robinson says.

“It’s pretty unusual to have single digits several says in a row.”

Hopkins recalled the ice storms of 2000-01. They kept down the fire ant population, he says, temporarily.

This does not sound promising for humans. How about individual, and especially loathed, insects?

Mosquitoes - “They’re going to come through just fine.” Go find an old barn around Stuttgart, Hopkins says. Go inside. There they are.

Fleas and ticks - Outside, they’re doing well, thank you, on wild critters. Inside, “they can overwinter in the house or on pets. Larva feed on grunge in the carpet, the yucky stuff the vacuum won’t pick up.”

Roaches - “They’re in the house all the time. If they’re outside they’re under the mulch and that protects them. The ones in the house, they don’t even know it’s winter.”

But there’s hope. Sort of.

“The next ice age that comes around will have an effect on insects. Humans, too.”

Style, Pages 23 on 02/18/2014

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