November is the time to winterize homes, cars, plants and even doghouses. Surviving winter demands preparation. It means caulking, putting up storm windows and doors, covering winter-sensitive plants with mulch, insulting dog houses and possibly getting a flu shot.
What about insects? What do they do when Old Man Winter blows his icy breath across the landscape? Well, they also winterize.
Winterizing for an insect is much like the process we go through to winterize a car. We add antifreeze to the car. Insects add antifreeze to themselves. If the liquid in the cooling system of a motor is allowed to freeze, the expansion during the process will break the radiator and hoses. The same is true of the liquid in insects. If it is allowed to freeze, the crystals that form will destroy the cells and tissues of the insect and cause death.
By adding antifreeze to an automobile's cooling system, the freezing point of the liquid is reduced so that freezing doesn't occur. This protects the system from damage.
As winter approaches, some insects use a similar antifreeze approach. In preparation for freezing temperatures, the water content in the insect is reduced. The water is replaced with glycerol, a compound similar to glycol that's used in antifreeze. Therefore, like the car, the insect is winterized. An insect's biological system is shut down and is protected from freezing during the cold winter months.
When the days become longer and the temperatures creep upward. The insect reverses the process. Glycerol is broken down and replaced with water. The insect is ready to resume normal activities.
In her poem entitled “About Caterpillars,” Aileen Fisher begins with this stanza:
"What about caterpillars?
Where do they crawl
when the stars say, ‘Frost,'
and the trees say, ‘Fall?'
Good question. But the important thing about an insect surviving winter is not where they crawl, but what they do when they get there. The successful insects winterize with antifreeze.