Where do the bugs of summer go when the weather turns cold? How do they reappear the next year when the temperatures warm? As cold-blooded creatures, insects are particularly susceptible to winter’s freezing temperatures. To survive, insects have developed a wide variety of adaptations, including long migrations, creating their own anti-freeze and even freezing portions of their bodies.

Migration is one strategy for escaping the killing temperatures. The Monarch Butterfly is the foremost example of migration. Each fall, between August and October, this insect heads south to Mexico. Other insects migrate -Crop pests are the most obvious of these migrants. But this list of insects includes milkweed bugs, Painted Lady butterflies and leafhoppers.

• verwintering as Larvae. Many insects successfully pass the winter as immature larvae. The protection of heavy covers of leaf litter or similar shelters protect the woolly bear caterpillar. Some grubs simply burrow deeper into the soil to escape the cold.

• verwintering as Nymphs. Not many insects are active in the winter, but the nymphs of aquatic insects like dragonflies, mayflies and stoneflies live in waters of ponds and streams, often beneath ice. They feed actively and grow all winter to emerge as adults in early spring.

• verwintering as Eggs. Few insects lay eggs which survive the winter. The most prominent insects in this category are Praying Mantis, and the Corn Rootworms also use this strategy.

• verwintering as Pupae. Some insects overwinter in the pupal stage, then emerge as adults in the spring. Moths in the Silkworm Family, may be found attached to plant branches as pupae in the winter.

Hibernation as Adults. Many insects hibernate as adults. Tree holes, leaf litter, and under logs and rocks are common shelters for overwintering adult insects. Ladybugs and box elder bugs, however, generally choose to overwinter as adults in wall voids, attics, and other out-of-the-way places in homes and other structures, as do a variety of wasps and flies, including yellow jackets, who are frequently found wintering in the eaves and attics of houses and barns.

Mourning Cloak butterflies and bean leaf beetles find warm shelters in tree cavities, beneath loose tree bark or in unheated buildings. Virtually anywhere they can fit into, to protect themselves from winter winds and keep them out of the view of birds and squirrels. Those who snuggle under tree bark prefer the south side of the tree, where it may be several degrees warmer on a sunny day. The Mourning Cloak Butterfly reduces the water content of its body, and builds up glycerol which acts as an antifreeze.

Collective Action: Social insects like ants and termites go to the deep reaches of their underground colonies that extend below the frost line. There, they feast on food they stored during the warmer months.

Another collective insect, honeybees, have a different adaptation to beat the wintertime cold. When the temperature of the hive goes below 64 degrees, bees huddle together in a ball, but remain semi-active. The interior bees generate warmth by vibrating their wing muscles. The outer bees are motionless, acting as an insulating layer. They take turns in the warm middle and the insulation layer. (The queen stays in the middle and does not take a turn on the outer layer). The consumption of up to 30 pounds of stored honey during the winter months gives the bees needed energy. Heat energy is also produced by the oxidation of the honey. Insects that are inactive during the winter months undergo a state in which their growth, development, and activities are suspended temporarily, with a metabolic rate that is high enough to keep them alive. Despite their strenuous efforts, bee colonies can potentially become completely lost or lose most of their members in a cold winter.

In general, insects are able to survive cold temperatures easiest when the temperatures are stable. Many insects can gain shelter and nourishment through the winter in a variety of micro-habitats. Among these are under the soil, inside the wood of logs and trees, and even in plant galls. Blankets of snow benefit insects by insulating the ground and keeping the temperature surprisingly constant. In comparison, vertebrates undergo hibernation, during which they have minor activity and add tissues to their bodies. They start doing things like putting on extra layers of fat. They also reduce the amount of water inside them. Although prepping their bodies provides some protection, freeze avoidant insects must also find shelter, and where they winter depends in large part on their stage of development. Those insects that spend the winter attached to a branch or twig, like the Goldenrod Gall Moth caterpillar, use the plant’s natural defenses to create their winter igloos: as the insect is attaching itself, the plant produces a cancer-like growth in defense, called a gall, which forms around the insect, shielding the insect from the elements. Grubs simply burrow deeper into the soil to escape the cold.

Though some insects may become unseasonably active during an extended midwinter thaw, the true hibernators and the majority of those that rest in the adult stage will not be tricked to becoming active early. Of course, that’s not much consolation to the homeowner who has to deal with a midwinter wasp buzzing the family or an “invasion” of slow flies bumbling into windows and walls during a midwinter mild spell. With or without antifreeze, most insects cannot function at temperatures below 40 degrees F because they rely entirely on the world around them for the warmth they need to live, they have developed this wide range of techniques for surviving cold weather and assuring the survival of their species.