We survive winter here in Colorado by living in warm houses and wearing layers and layers of polar fleece and down. How do insects survive?
Some insects, such as boxelder bugs and yellowjackets, spend the winter as adults in protected areas, under loose tree bark or under the shingles of your house. Insects that over-winter as adults usually enter diapause — “an inactive state of arrested development” (sounds like me yesterday, watching the snow fall). During diapause, their growth, development, and activities are suspended, with a metabolic rate that is high enough to keep them alive. Diapause is triggered when daylight starts to become shorter in the fall. Warm temperatures tend to wake up the insect from diapause. This usually takes a long period of warm temperatures; it would be a mistake to wake up too soon.
There are many strategies for surviving winter. Monarch butterflies migrate to the mountain highlands of Mexico. Dragonflies and mayflies spend the winter in ponds and overwinter as nymphs. Others overwinter as eggs (aphids), larvae (corn borers) or pupae (swallowtail butterflies). Some insects replace the water in their bodies with glycerol, which act as an “antifreeze”, so the cells in their bodies can reach temperatures below freezing without forming ice. With or without antifreeze, most insects simply cannot function at temperatures below 40 degrees F. Because they rely entirely on the world around them for the warmth they need to function, they have developed this wide range of techniques for surviving cold weather and assuring the survival of their species.