This was a recent question from our “Ask The Bug Doctor” page and it’s actually a very good one. I’d say most people think of bears when they think of a creature hibernating for the winter. We picture the momma bear in a cave somewhere sleeping the cold winter months away all warm and cozy & her body living off of the fat stored up from a summer time of gorging herself on berries and honey she’s stolen from any unearthed bees nests. Oh how I wish I were a bear at times.
Insects however are cold blooded and can’t generate heat but we know that they disappear (for the most part) in the cold winter months only to find them in the spring ready for another season. So how do they do it?
First, not all insects survive the same way; Bees stay semi active and heat is produced from the honey in their hive as it oxidizes. Monarch butterflies migrate to escape the cold and others may survive in one of the many stages of development either as an egg, pupae or larva.
The most intriguing way are the insects that produce an ‘anti freeze’ in their bodies to keep from succumbing to the cold. Although complicated it is basically glycerol produced by the bug that allows it to survive the long cold winter months.
glycerol |ˈglisəˌrôl; -ˌräl|
a colorless, sweet, viscous liquid formed as a byproduct in soap manufacture. It is used as an emollient and laxative, and for making explosives and antifreeze. • A trihydric alcohol; chem. formula: CH 2 (OH)CH(OH)CH 2 (OH).
As best I can tell this chemical is produced seasonally perhaps triggered by the colder temperatures and is not a conscious choice. Warmer weather triggers the insects normal functions to kick back in and although it may take some time the bug returns to normal ready to do what bugs do. This survival technique is not always fool proof however and fluctuating temperatures may trick the insects body to come out of this state to soon. Once the freezing temps return it may not be able to produce the glycerol again or in time and it may die. Even with this chemical protection these insects still will find protected places in which to hide as further insurance of their survival. This is why so many times you will find insects in your home alive in the dead of winter either brought in with the firewood or woken up by the heat produced from your furnace. The term for this characteristic of insects is called ‘over-wintering’ and it’s just one of the many fascinating aspects of a bugs life.