Where Do They Go?
Nature Bulletin No. 726 October 5, 1963
Forest Preserve District of Cook County
Seymour Simon, President
Roberts Mann, Conservation Editor
WHERE DO THEY GO
Walking through the meadows, fields and prairies on a balmy autumn
day we hear the chirps, trills, buzzing and humming of innumerable
insects. Many kinds have been multiplying since spring until their
populations are beyond comprehension.
dance in the air and flutter from flower to flower. Bees are
industriously gathering nectar and pollen. Scads of startled
grasshoppers and crickets leap and scatter ahead of us. The ground is
alive with myriads of ants, bugs, beetles, caterpillars and smaller
forms of insect life. In the woodlands, great companies of insects creep
down from trees to find winter homes in weeds or the litter and humus
beneath fallen leave.
Inevitably there comes a night when the temperature drops much
below the freezing point and the vegetation is thickly coated with frost.
On the following day no insects are seen or heard. Where did they go.
The grasshoppers died. So did all but a few species of butterflies,
moths, and the adults of many other kinds of insects whose young,
however, pass through winter in the egg stage or hibernate as larvae,
pupae, or nymphs. The ants huddle in their burrows. The honeybees
huddle in their hives. The bumblebee queens and the queens of
colonies of social wasps have crept into protected places where they
hibernate until spring, but the males and workers died.
All of the male mosquitoes died. Fertilized females of the common
house mosquito (Culex pipiens), and of the Anopheles mosquito which
transmits malaria, congregated in cellars, catchbasins, hollow trees
and other protected places where they hibernate. The woodland and
floodwater mosquitoes winter over as eggs.
Housewives are unpleasantly familiar with the adults of insects which,
seeking places to hibernate, manage to creep through cracks and
invade our homes: houseflies, the bluebottle and greenbottle blowflies,
wasps, lady beetles, and that harmless nuisance -- the boxelder bug.
A few species of butterflies and moths migrated southward earlier in
autumn: notably the Monarch butterfly -- sometimes in vast flocks,
sometimes as far as the West Indies -- and some of them, tattered and
torn, return in spring to lay eggs on young milkweeds. Adult angle-
winged butterflies, such as the Mourning Cloak and Red Admiral,
hibernate in outbuildings or hollow trees and become torpid but, on
balmy winter days, may emerge and flutter aimlessly about.
Some kinds of adult insects can endure long periods of extreme cold
while hibernating if those periods are continuous -- not interrupted by
warm thawing days -- and some, believe it or not, survive being
The Viceroy, the fritillaries, and the little skippers, are butterflies that
hibernate as caterpillars. The swallowtails and the white cabbage
butterfly are some of those that hibernate as pupae -- naked chrysalids
not protected by cocoons.
Some of the moths --especially the tent caterpillar, bagworm,
cankerworm, gypsy moth and other injurious kinds -- pass through
winter as masses of eggs. The woolly bear caterpillar, larva of the
Isabella tiger moth, is a familiar example of those which hibernate in
the larval stage. The caterpillars of many kinds of moths, however,
spin silken cocoons around them and change into pupae before winter
comes. Most youngsters are familiar with and collect cocoons of the
big silk moths -- the Cecropia, Promethea, Polyphemus and Luna
In winter, if you turn over a rotting log, you may find a mouse's nest, a
torpid snake or a salamander, a woolly bear caterpillar curled up
tightly, and the pupae of beetles or other insects. Please put the log
back as it was.
You may learn far more about "Where Do They Go" from the Field
Book of Animals in Winter, by Dr. Ann Morgan, published by G. P.
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Update: June 2012