Nature Bulletin No. 142 Febraury 14, 1948
Forest Preserve District of Cook County
William N. Erickson, President
Roberts Mann, Supt. of Conservation
Insects pass through the winter in every stage of their lives: some kinds
as eggs, some as larvae, some as pupae, some as nymphs, some as
adults. Only a few, notably the Monarch butterfly, migrate southward.
Of those that hibernate as adults, there are a few butterflies.
The Mourning Cloak butterfly spends the winter in barns or sheds or
hollow trees, and on unusually warm winter days they may emerge and
fly about -- good-sized butterflies with rusty black wings spotted with
blue and bordered with pale yellow.
Ladybird beetles, or "Lady bugs", hibernate in big colonies under the
loose bark of trees, in tree cavities, and in buildings. On warm winter
days they may come out and crawl around. House flies, and the blow
flies known as Bluebottles and Greenbottles, winter in cellars, attics and
the crevices of buildings. If the temperature rises above 50 degrees,
they will crawl or fly aimlessly about.
Many adult insects spend the winter underground. The May beetle, or
"June bug", burrows down below the frost line. So do most kinds of
ants. The young queen bumblebees lie dormant in burrows well below
the ground surface. Many insects spend the winter as adults in or under
rotting logs; some beneath the leaf mold or in the topsoil of woodlands;
some among grass roots or in bunches of grass. Some beetles, for
instance, get ready for hibernation by storing up fat, like bears. Other
insects seem to be able to eliminate water from their bodies and can
endure freezing temperatures for weeks at a time.
In general, uniformly cold winters with plenty of snow are easiest on
insect life. Next best, are very mild winters with little or no freezing.
Cold winters with occasional warm thawing days, and warm winters
interrupted by severe cold spells, are both disastrous to many kinds of
The snuggest bug is in a rug.
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Update: June 2012