Nature Bulletin No. 518-A February 23, 1974
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
That first small crater-like ring of soil granules heaped up around a
crack in the sidewalk is a sign of spring. Hesitate there a moment --
children always do -- and you'll see several Little Black Ants hurrying
in and out, bringing up particles of earth from below as they enlarge
their underground home. At another time you may see columns of
them in an ant safari with two-way traffic as they cross a lawn or
invade a kitchen to forage for food.
All ants live in colonies. Ants are called social insects because within
each colony there is a division of labor with males, females and one or
more castes of workers each performing certain tasks for the benefit of
the whole group. A single colony may vary in size from a few dozen
individuals up to millions. Some naturalists suppose that ants are more
numerous than any other type of land animal others think that plant
lice outnumber them.
In most kinds of ants a new colony is started by a young queen.
Immediately after the mating flight she loses her wings, then digs a
hole in the ground or finds a cavity under a rock or beneath the bark of
a tree. There she walls herself in and remains for weeks or months, a
voluntary prisoner. During all this time she does not eat but is
sustained by stored fat and the large wing muscles which are now
useless. First, eggs are laid which hatch into larvae. The queen nurses
these on saliva until they transform into pupae which look like small
oblong capsules and are often mistakenly called "ant eggs ". From
these emerge abnormally small, wingless workers called "minims".
Commonly, the three stages -- egg, larva, and pupa -- each require
about three weeks.
This first brood of workers digs out of the cell and begins to gather
food for itself and its mother. Then she lays more eggs, and the
workers take over the care of the new larvae which appear. Because
they are abundantly fed, these produce workers of a larger caste. All
workers are imperfect females which rarely lay eggs. Now the colony
increases rapidly. New chambers and galleries are excavated. For the
remainder of her life, which may reach 15 years, the queen is merely
an egg-laying machine. In later years, males and females with wings
suddenly appear outside the colony and launch into their nuptial flight.
These young females start new colonies and the males die a day or two
later. The queens come from larvae which have been specially fed, and
the males come from unfertilized eggs.
Various ants eat almost any kind of plant or animal material. Cookie
crumbs -- a combination of sugar, starch and grease -- seem irresistible
to many of them. They are also great scavengers, stripping flesh from
the bones of dead animals and drafting away dead insects. Some kinds
are best known for their habit of keeping "ant cows" -- plant lice or
aphids -- from which they coax a sweet fluid called honeydew.
The Army Ants of tropical America and Africa are famous for their
predatory habits. No living thing along their line of march, even man,
can resist their tearing jaws. The Leaf-cutting Ants feed on fungi
which grow on chewed up foliage in their subterranean "mushroom
gardens". Some of our local ants raid the colonies of other kinds, carry
away their pupae, and make slaves of the workers that emerge from
things are more interesting in the schoolroom than a healthy
colony of ants in an observation nest. Detailed information about that
is given in Service Leaflet No. 35, which may be obtained from the
MacMillian Science Co., Inc., 8200 South Hoyne Avenue, Chicago 20,
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Update: June 2012