Have you ever wondered what insects do in winter, when it is too cold to eat and multiply? Where do they go? The famous Aesop fable “The Ant and the Grasshopper” gives us a clue as to what happens in nature when winter approaches.
When the winter wind blows in…
Insects are great champions of adaptation; to survive our long winter, they have developed vital physiological acclimatization techniques. In the fall, as daylight and temperatures drop, they get rid of excess water in their metabolism and accumulate molecules of glycerol, which serves as an antifreeze. With the exception of a few species, such as the monarch butterfly, most insects stay in Québec. They may spend winter as an egg, larva, nymph or adult. Entomologists call this period of inactivity “diapause."
A few proven survival techniques
- Resilient eggs – To increase their chances of survival, many species of butterfly lay their eggs sheltered from the elements and out of sight of predators. Praying mantises protect them in an egg case. Mosquitoes’ eggs spend the winter under the ice in ponds and other bodies of water.
- Hidden larvae – To avoid freezing, many beetle larvae, such as June bugs, burrow into the ground. Others take shelter inside plants (stems, leaves, roots).
- Protected nymphs – Many ephemera, dragonflies and stoneflies spend the winter in the nymph stage, hidden at the bottom of rivers, lakes and ponds. The first rays of springtime sun break through the ice and snow, allowing the insects to escape the water. They then moult for the last time, emerging as adults. Many species of moth spend the winter at the chrysalis stage, inside a cocoon—this is the case of two of our largest species: the cecropia moth and the polyphemus moth.
- Sleeping adults – Ladybugs group together in impressive numbers at the foot of trees, sheltered from the wind and generating enough heat to survive. Thanks to glycerol, some can withstand temperatures as low as -30 °C. Other beetles can survive -60 °C. Meanwhile, ants burrow into the ground to protect themselves from the cold. Future queens of 14 species of social wasps in Québec spend the winter in the adult stage, hidden in a bed of leaves or a pile of bark.
A few species remain active in winter in Québec. Crane flies in the Chionea genus, nicknamed “snow flies,” prefer to carry out their breeding cycle in the winter rather than the summer. So get outside and discover all these insects that endure Québec’s cold, harsh winter!