Insects make their own antifreeze, but it might not be enough this winter

For the people on P.E.I. this winter of mild temperatures and little snow has been an easy one, but for the Island's insects it's been a different story.

"Two things happened this winter: one is fluctuation of temperature over a long period of time, the other is we have had rain and a flash freeze," said Christine Noronha, an entomologist with Agriculture Canada.

The flash freeze can be a quick death for insects.

"They get wet, the ice will enter their body and it will kill them," said Noronha.

The fluctuating temperatures create a more complex problem for bugs.

Depleted reserves

Insects spend the winter in a state called diapause, which is like a very deep form of hibernation.

To survive diapause, insects need to build up reserves in the fall, then they bury themselves underground, under leaf litter, under the bark of trees, and other cozy places, and produce a natural antifreeze to get through the cold weather.

When temperatures get close to double digits, the insects start to come out of diapause. They breathe more quickly, and this uses up reserves, and then when the cold returns they have to produce more antifreeze, depleting more reserves.

"It's very difficult," said Noronha.

"That depletion in reserve can cause them to either die, or they can come out of diapause early."

If they come out of diapause early, they may find there is no food for them to eat, or earlier depletion of reserves could mean they won't have the strength fly to where their food is.

"You're going to see them, but they're going to die," said Noronha.

Noronha estimates that certain insect numbers could decrease by 20 to 30 per cent. That includes black flies, mosquitoes, and certain agricultural pests. Pests that overwinter in the soil will not be affected as much.

But low insect numbers in the spring will not necessarily translate into a less buggy summer. Insect populations rebound quickly, Noronha said, and by midsummer the effects of the hard winter will likely have passed.

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