Global menu

Insects and other arthropods

How do insects survive the winter?

The chrysalis of the black swallowtail butterfly, from the first generation of caterpillers, is green and blends in with its summer environment.
Photo: Insectarium de Montréal (René Limoges)
Papilio polyxenes asterius, Québec, Canada.
  • Papilio polyxenes asterius, Québec, Canada.
  • Papilio polyxenes asterius, chrysalis, Québec, Canada
  • Nymphalis antiopa, Québec, Canada.

Arthropods, including insects, are cold-blooded animals, which means their vital functions, including feeding, movement and reproduction, depend on the ambient temperature. For this reason, they are very vulnerable to the significant temperature decreases in the wintertime. Arthropods have adapted in a number of ways in order to survive the winter.

An ingenious strategy

Generally, the winter adaptation process takes several weeks and begins once the days become shorter at the end of the summer. In addition to waiting for milder temperatures to arrive in the spring to complete the stages of their development, insects and other arthropods reduce the quantity of water that their bodies can hold. They also accumulate small molecules of glycerol in their blood, called hemolymph, that act as antifreeze for them during the winter. When cold weather arrives, they go into “diapause,” a state of almost total metabolic inactivity.

Glycerol is a type of alcohol that keeps the body’s cells from breaking. It keeps the water inside the organism from freezing and producing ice crystals that would destroy the cell walls, leading to the organism’s death. By keeping water molecules from crystallizing inside their tissues, arthropods greatly increase their chances of survival. They can survive in temperatures as cold as –30°C and sometimes even lower.

If tropical species without this capacity to resist the cold end up here by accident, they will not survive the winter.

Add this