Most insects shelter from the elements by a layer of leaf litter, soil, and special adaptations.
In temperate areas, winter is the hardest time for insects to survive. Low temperatures, infrequent water and scarce food all combine in winter to make it simply unlivable for the vast majority of insects.
This is easily observed as once boisterous landscapes become quiet shadows of their former selves once frost begins to set in. While it may seem that most animals in the ecosystems around you disappear completely during the winter, in fact most of your insect neighbors take shelter in plain sight during the colder months. Using a wide variety of techniques, these insects are able to survive long periods of time in dangerously low temperatures while staving off the effects of thirst and hunger. The methods used for such spartan living tend to differ between species. Many insects possess multiple varied forms throughout their lives from egg to adult, and there is usually one form that specializes in surviving the winter. By learning how these important animals outlast the cold, it can be easy to make sure your property is arranged in a way that ensures a cozy winter retreat for the beneficial insects in your area.
Most insects spend the winter as an egg or immature form, sheltered from the elements by a layer of leaf litter, soil, and special adaptations. Some worms, for example, die in the winter and leave protected eggs in the soil that hatch in the spring. Larger worms burrow deep into the soil to prevent from freezing. A few insects use the mobility of their adult forms to simply run from the cold, as in the case of monarch butterflies who travel thousands of miles to avoid being frozen, using UV rays and other subtle clues as guidance. Many aquatic insects take shelter at the bottom of ponds or lakes. Social insects like ants and honey bees huddle together to keep warm and either feed off of collected stores or enter a torpid (inactive) state. Most of our other native social insect colonies, such as bumble bees and paper wasps, die off and leave only new queens to survive until the spring, sheltered in leaf piles or thick mulch. These queens, along with a host of other insects, are then forced to find a way to keep from freezing.
Simply put, in winter many insects find a way to either prevent their bodies from freezing entirely or they control exactly where they freeze, sacrificing sections of their body for the greater good. They are able to do this by pumping their bodies full of specific sugars and in some cases also dehydrating their cells, turning themselves into living insect jerky. Many of these animals also enter a state called diapause, which is basically hibernation but the participant is sometimes also semi-frozen. Even insects that only live for a few weeks in their adult forms are able to prolong their lifetime for months or years in their inactive and protected state, quietly waiting for their preferred weather to return.
It seems that most insects take their cues to prepare for winter based on shorter day lengths rather than dropping temperatures. Because of yearly temperature variations, this can sometimes mean that an insect finds itself in colder temperatures that it would like. This is especially dangerous to small, cold-blooded animals like insects who lose muscle function at cold temperatures. Luckily, many insects are able to warm in the sun and flex certain muscles in order to warm their core temperature to levels allowing for movement. Flying insects require their flight muscles to be especially warm to perform at optimum efficiency. These insects are able to utilize the incredibly complex and powerful engines strapped to their backs to help. The flight muscles that flying insects require are gargantuan—around 15 percent of their total mass—and are able to produce some serious heat through contracting. If that isn’t sufficient, some species such as bumblebees have been found to also generate extra heat through chemical reactions in or near their muscles. As we learn more about the ways in which insects are able to survive harsh temperatures and conditions, perhaps we will be able to apply some of their time-worn strategies to our own lives.
Help insects in your area survive the winter
The insects on your property are already tucked in for the season, so keep that in mind as you go about your winter chores. Avoid cutting down or pruning any trees or shrubs in the winter, as beneficial insects could be sheltered on their branches and trunks. Winter pruning is also damaging to most plants (prune in the spring or directly after said plant blooms). Try not to pile snow very high in natural areas, as this can lead to ice buildup that is slow to melt. Leave any pithy-stemmed plants or grasses that you cut to at least a foot in height, to give insects sheltered places to settle down if needed.
Leaf piles, thick mulch, and other similar locations are important overwintering sites for insects, especially bumble bee and wasp queens. Established leaf piles on the fringes of a property are a great way to foster local populations of beneficial insects. As you add to the piles year after year, it won’t be long until your yard is the area’s premier winter retreat. A final tip—go light on the ice melt. The salt found in most concoctions can work its way into the soil, where it can damage plants as well as animals living underground.