Insects in winter

Written on January 17, 2014

Winter’s coming on fast. The trees are losing their leaves, the temperatures are dropping, and then there’s the daily reduction in daylight as well – these are harbingers of a change in seasons. But what happens to insects in winter?

No doubt at some point this question has crossed your mind. And you might be surprised to learn that the majority of insects survive the winter. However, unlike humans, who maintain a constant body temperature regardless of their environment, insects are “cold-blooded” animals, meaning their internal temperature varies according to ambient temperature. While we bundle up, insects make use of ingenious adaptations to deal with the cold.

Some decide to take off

Some insects avoid winter quite simply by leaving their habitat and heading south, on the lookout for a more moderate climate. We call that migration. One well-known example is a butterfly that’s very popular in Québec, the monarch. Each year, at the very beginning of autumn, the fragile-looking butterfly travels4,000 kilometersto the high mountain areas of the state of Michoacán, inMexico. The butterflies spend the winter there by the millions, until the return of nicer weather.

But this reaction to winter is not what usually happens. Most insects have adapted to their environment and remain there, resorting to different strategies, each one more fabulous than the last.

While others dig in

Just as we fall into the arms of Morpheus for a long, deep sleep, a majority of insects find shelter somewhere and slip into a state of torpor, thereby reducing their expenditures of energy. Similar to mammals who hibernate, insects go into diapause. In that state they can spend the winter in one or another of the stages of the life cycle, whether in the form of an egg, a larva, a nymph or an adult. Hidden under the bark of trees, under the ice, the ground, litter, or sometimes in our homes, insects escape the harshness of the climate. Even snow serves as a refuge by offering insects an insulating cover that will protect them from the cold and from predators until the return of spring.

Alcohol in the “blood”

Insects never stop surprising us. One of the most impressive strategies of insects who spend the winter in Québec is their ability to produce an effective antifreeze consisting of glycerol. Glycerol, a molecule preventing the formation of ice crystals, replaces the water in and around cells.

Carrying on despite everything

Finally, for a few rare insects, active life continues at the heart of an immaculate landscape. Have you ever noticed, in winter, what looks like little black grains of sand under the carpet of snow? If you get closer and focus your gaze, an unsuspected scene comes to life: little indigo blue arthropods, millions of them, indulging in remarkable acrobatics, as though celebrating the ice on the ground. These are springtails, commonly known as “snow fleas” (Hypogastrura nivicola). And although they’re not really fleas, they have the ability to leap to heights as much as 50 to 100 times their size. These feats are possible thanks to a fork-shaped appendage on the underside of their bellies known as a “furca“.

Insects in winter – what an amazing world!

We’ve had a look at some of the tactics brilliantly executed by insects to avoid the effects of winter. No doubt when spring returns we’ll take a different look at these little-known but fascinating creatures!

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