WHY DO THE ANTS GO MARCHING?
Ask students if they have seen ants. Their answer should be YES
(since it is estimated that out of one million trillion insects
alive on earth (10 to the 18th), approximately one percent of them
are ants, which equates to 10 thousand trillion ants, divided into
more than 9,500 species of ants. Ask students where they see ants,
and they will probably answer that they see ants EVERYWHERE! This
is definitely true, since they live almost everywhere in the world,
and they have been around for more than 100 million years. Show
students pictures and/or drawings of ants. Ask students what ants
do and why they are often seen "marching." Reinforce that
ants are the chief predators of insects and spiders, and collect
more than 90 percent of all dead insects to bring back to their
nests. Also, ants move more soil than earthworms do and are responsible
for moving nutrients and plant species throughout the ecosystem.
The scientific study of ants is called myrmecology. Brainstorm a
list of questions your students have about ants and list these on
the chalkboard. Visit http://www.antcam.com/
and view ants through their live ant cameras. See if your observations
can help you answer the questions your students developed, as well
as some of these questions: Do ants talk? Do ants sleep? What do
ants eat? Do ants "go to the bathroom"? How long do ants
live? Are all ants female? Where do ants go when they die? How can
you tell ants apart? Do ants ever get sick?
MAKE A FORMICARIUM
(Or you can call it an ant colony!) Check out insected.arizona.edu/antrear.htm
for information on keeping ants in the classroom. Ask students to
make observations of the formicarium at specific times and record
this information in a class log. Each day or week, have students
make news broadcasts about the activities of their ant colony. Develop
an ant newspaper with articles, advertisements, letters to the editor,
want ads and other journalism examples written by the students from
the ants' point of view. Publish this newspaper for other students
to read and enjoy.
COMPARE AND CONTRAST CARTOONS
What's the difference between thatch ants, carpenter ants, fire
ants, samurai ants and other species of ants in the world? Ask students
to research and develop compare/contrast cartoons to show what they
have learned. Since over 9,500 species of ants have been discovered
so far, students have lots of ants from which to choose!
WHAT ABOUT THE APHIDS?
Ask students to try to find some aphids on the leaves and stems
of plants in their garden. Using a magnifying glass, ask students
to draw a sketch of an aphid. Describe how ants "milk"
the aphids to get them to release the liquid called honeydew.
VIDEO OVERVIEW AND SUGGESTIONS
As you view the video "Thatch Ants" with your students,
use the timecodes and video transcript as needed to stop and start
the tape, discuss the information and visuals, and guide your students
as they explore this topic. Ask them to write down any terms that
are unfamiliar to them and use the glossary after the program to
define the terms.
We are beyond the suburbs and the farms in Central Oregon's
sagebrush country. It is probably home to coyotes and bobcats.
But we are here to observe life on a scale so tiny it is often
ignored. There is an entire world under foot, a social system
operating here beneath the weeds. This is thatch ant territory.
And our miniature camera is exploring one of the many ant
trails that radiate like spokes from the primary nest.
The trails are lifelines as the colony collects the food it
needs to survive. Our trail is alive with worker ants bearing
the trophies of almost endless scavenging.
We must slow the action in order to observe the frenetic scene,
and as we do, this ant world under the Central Oregon sage
begins to reveal its secrets.
"I think that they're amazing creatures."
Jim McIver has spent seven years studying thatch ants in
Oregon. The word "thatch" pertains to the
straw-mat-like coverings civilizations often use building
shelters. In similar fashion, thatch ants construct nests
of carefully interweaved twigs. "That nest structure
results from the collective behavior of hundreds of workers
that are striving to keep that thatch structure up high. So
the net result of all their activity will be a movement of
thatch from down below to up high."
A colony is like a living creature and the ants are its
moving parts. This is a big colony, a regular ant factory,
which will produce 25,000 workers in a year.
The mound breathes as air circulates through the sides and
out the top of the nest. But wind and rain and gravity work
to flatten and suffocate the structure. Workers struggle to
maintain ventilation, constantly tugging the countless twigs
back into place.
To fuel this and the other critical demands of survival, the
colony has a voracious appetite. "The colony basically
needs two types of food and it's sort of analogous to honeybees.
Honeybees need pollen and nectar. Ants need protein and honeydew.
They need protein and some kind of carbohydrate for energy.
And so the economy of the colony is built around collecting
these kinds of foods.
High in the branches of a sage plant, some workers perform
a singular food gathering task for the colony.
"Each of the ants has her own clump of aphids that she
tends to specialize on and she'll circulate around and harvest
honeydew from that group of aphids all day long."
It is a kind of microcosm of life in this Central Oregon
range land near Prineville. The thatch ants tend livestock,
minute aphids that infest the sage.
"Antennae of the ants move constantly. They use the antennae
to stimulate the rear end of the aphids so that they'll excrete
a little bit of a little droplet of honeydew.
The ants that work the aphids become living storage tanks
for the honeydew. Each worker can transport half its weight
in honeydew from the sage to the nest. At the nest, the sugary
fluid will nourish larvae, young workers and the queen. The
honeydew harvester carries the honeydew in a receptacle in
the forward part of her abdomen. That natural container is
called a "crop." To estimate the honeydew that's
stored in her crop we take this capillary tube and put it
up against her mouth at the same time as we gently squeeze
her abdomen. Honeydew is just like, basically, sugar water.
It has about the sugar concentration of orange juice.
Numberless workers lap up uncounted droplets provided by
the aphids, mostly from sunup to dark, collecting enough honeydew
to help fuel the colony.
But there is more to the diet requirements of the colony.
And the worker ants can be as fierce as any other carnivore.
To survive, this colony alone must feed on the carcasses of
a half-million insects annually. Several yards from the nest,
an injured honeybee has been caught in the ants' unending
sweep. Workers cannot easily move so big an object. That problem
will be remedied, though, by sharp mandibles and relentless
tugging. "They've got it pinioned and it's much too large
to transport back. So they'll cut it into pieces. And they'll
take the head back by itself. And they'll take the wings off,
which they can't eat. And then divide the body up into parts,
take those back to the primary nest.
The ants are excited by the presence of prey or predator.
And through some unknown mode, perhaps a chemical or visual
cue, the excitement spreads.
The lure of the bee has distracted the ants from our miniature
camera. But without the bee, the camera is subject to immediate
attack. The aphid tenders, too, are ready to do battle with
an alien object like a lens. The worker assumes her classic
defense posture, curling her abdomen under and spraying formic
acid at the intruder. Any worker will give her life subduing
prey or defending against a predator. There is no hierarchy
among the ants. There are no leaders. Even the queen, producing
eggs deep in the nest, has no authority. "There are no
workers that are superior to other workers. There are no foremen.
All the workers are basically identical or equal."
Each spring, the successful colony will generate a new brood
of queens and drones that fly off and establish other colonies.
And so, by some little understood mechanism, the colony operates
year to year. The workers somehow divide the tasks without
benefit of a central authority to coordinate the complicated
So how they get the work done is probably one of the biggest
mysteries. Each individual is programmed with certain information.
She's programmed to recognize certain types of communication
signals from her sisters and she's programmed to respond to
the environment in very basic ways. But a large part of her
behavior is also due to her individual experience.
Jim McIver tags thatch ant workers. He can track them month
after month. He feels he has a lot more to learn. "One
of the values of studying other living things is finding our
Careful observation of apparently random behavior may offer
more clues to the order of the colony. The mindlessness of
the individual somehow yields to a consistent teamwork the
colony depends upon for survival.