All About Ants (almost) Essay, Research Paper

All About Ants (almost)

Among the many hundreds of thousands of astonishing organisms with which we must

share this earth, there is one seemingly ordinary group of specimens which

fascinates many people beyond all others. There is nothing too extraordinary in

the proportions or appearance of ants, but it is their history and culture that

induces a second look. These insects are about as different from us mammals as

two organisms can be, yet it appears that of all the known animals their way of

life appears closest to our human way of life. The similarities in the ways in

which we organize our lives are astounding. Ants are doubtlessly the most

successful of all the social insects of the Hymenoptera, an order also including

wasps and bees.

The earliest known specimens are found entombed in the Scandinavian Baltic Amber

samples which scientists date in upwards of 100 million years old (The Ant

Colony ?89). These primitive samples have evolved into the 5000 to 10000

species known today which vary amongst themselves as widely as the numbers

suggest (Social Insects ?68). These remarkably adaptive creatures are found in

some form on all continents and all habitats but the extreme arctics. Their

success is manifested in the claim that at any time there are at least 1

quadrillion living ants on earth(Groliers ?93).

All species of ants are social. They live in organized communities or colonies,

which may contain anywhere from a few hundred to more than 20 million

individuals. These are organized into a complex system which may contain two or

more castes and sub castes which can be roughly organized into three groups.

Queens, males and workers.

The queen is much larger than the other ants, and has wings until mating. Her

primary task is to lay eggs for the colony. Some colonies have one queen;

others have up to 5000. Queens develop from fertilized ordinary eggs, nobody

is exactly certain what causes these to develop into queens but it is generally

thought that the process comes from an altered diet in the pupae and larvae

stages and as a pheremone response, which will later be discussed. Queens have

an extended life span of up to 25 years and can lay millions of eggs in that

time (Ant Colony ?89).

Male ants are winged as well, their sole purpose is to mate with the queens.

For this reason they are the shortest lived ants in the colony. Hatching in the

spring, they mate in the summer and upon completion of this task promptly die.

As in all Hymenoptera, they are formed from non-fertilized eggs (Social Insects ?

65).

The majority of the ants in the colony are wingless females who are generally

non-reproductive. These “workers” must perform the tasks of sustaining the

colony and all life therein. They are responsible for building, repairing, and

defending the nest, and for caring for the queen and the brood. They also

generate a source of nutrition and feed all the members of the colony. Some

will will perform a single task for their whole lives, while others change

constantly.

In polymorphic species, where the workers vary in size, the worker sub casts

are most destinguishable. Here there is found a larger or major worker often

referred to as a soldier. Her function is often associated with specialization

such as guarding the colony, carrying heavy loads, or in species where necessary,

foraging for food. While the minima or smaller workers tend the larvae and

queen.

Once or twice each year, commonly on a warm summer day, every ant colony becomes

the source of great excitement. Well rested and cared for young alates begin to

make for the escapes and exits from deep within the colony. Large soldiers

guard the door as the young winged members are escorted to the open by hordes of

workers. Suddenly, yet unbeknownst to man nature gives a signal. Soldiers

retreat, and workers make space and assemble on the ground as the males and

queens are hustled to the sky. Hastening into the air they often meet with

winged’s from other colonies with the same objective. For the first and only

time in their lives they will mate, often in mid-air or settling on leaves and

branches. Now the queen is equipped with a lifetime supply of sperm. After a

brief hour or two of this nuptual flight they return to the ground. Males

having accomplished their duty die, while the queens task has only begun. She

will return to her original colony, inhabit another established colony or form

her own.

Not all queens will survive this lonely dangerous task. Her first objective is

to shed her wings, for she will never fly again. She breaks them off herself,

or is aided by worker ants. If she is to form her own colony she goes about

finding a spot . Depending on her species any wide number of sights may be

chosen. In the majority of cases a queen will tunnel a cell underground. She

uses her jaws and forelegs to move the earth. Alone and unprotected she seals

herself into her new home. Then, following a variable gestation period she lays

her eggs. It may be nine months before the first workers hatch(A closer Look ?

75). She must find food in this time when she is all alone busily laying eggs.

Her body is able to break down her no longer needed wing muscles from which she

may gain nutrition. Often she must eat some of her eggs to survive(Groliers ?

93).

The first ants that hatch are workers. This first group is consistently smaller

than workers to come. As you will find out they did not receive the same

nurturing that will become standard for the brood in a fully functioning ant

colony. They instinctively venture out to find a way to feed their feeble

mother. From now on, she will be cared for as true royalty, licked and fed by

the nurse workers, her only job, to lay a lot of eggs.

Once she has been attended to, these busy workers will go about the task of

enlarging and enhancing the anthill. First they will provide a place for the

brood. Those that live in the earth tunnel chambers in the soil, these are

logically referred to as nurseries. Here the eggs and smaller larvae are cared

for.

Insect development consists of three stages. The first of which is the egg.

These are carried to nurseries as soon as they are laid. Each chamber differs

in temperature and humidity. In order for the eggs to develop properly the eggs

must have a temperature of 77 digrees F(Colony ?89). Nurses move the eggs from

room to room. These chambers are often found in the deepest recesses of the

colony. By licking them the sticky ant saliva causes the eggs to cluster

together, for easier carrying. After 14 days this first stage is complete as

the tiny larvae hatch(Colony ?89). These larvae lack legs and eyes and hardly

resemble adult ants. The helpless infants rely on the nurses to feed and clean

them. This developmental stage requires a temperature of 82 degrees F with a

high humidity, as a result the larvae are stuck together and carried about just

as the eggs are(Colony ?89). They receive a special diet as well. For the next

8 to 20 days the larvae grow quickly(Colony ?89). So quickly, in fact, that

they will grow right out of their skin. “Bursting at the seams,” they slither

out as do snakes. When this has taken place four or five times they enter into

the third stage and pupate. The larvae excrete a white solution which quickly

solidifies upon contact with the air. This is spun into a protective cocoon,

which looks very much like a large egg. For an unknown reason, there are a

number of larvae which go through pupation without a cocoon. Their colorless

legs and antennas are pushed helplessly to their bodies, giving the same

appearance as their counterparts within cocoons. In a dry location of 86

degrees F, they finish up their childhood near the surface of the anthill where

they may be seen from the outside. After two to three weeks in the cocoon the

transformation is complete. Gnawing a hole from the inside, the nurses are

alerted of their condition and aid them in escape. For the first few days the

exoskeleton has not hardened so the young ants body is soft. It’s chest

(thorax) is li ght brown, legs are pale, and heads and abdomen are gray. Still

vulnerable, if they are in danger, they are swept to safety by nurses.

The body of an ant is divided into three segments which are the head, thorax,

and abdomen. On the head are antennae, eyes, and mouth parts. The tiny feeler

like antennae are perhaps the Swiss Army Knife of the insect world as they

enable the ant to touch, taste, smell and sense vibrations. These antennae are

also used to help the ants communicate with each other. All worker ants have two

compound eyes, these sense organs are made of many lenses set close together,

each lens seeing a tiny part of what the creature is looking at , the combined

effect is a fragmented picture of the whole object. This means of vision is

beneficial to the ant because it enables them to very easily see movement.

Males and queens do not, however, need such a complex system. They have three

simple eyes on the top of their heads called ocelli which distinguish between

light and dark(Groliers ?93).

The two primary mouth parts are mandibles and maxillae. Mandibles are a moving

jaw like apparatus. These are used for fighting, digging and carrying objects.

The smaller maxillae reside behind the mandibles and chew food. On the front of

the maxillae is a row of tiny hairs which operate like a comb to clean the legs

and antennae.

The middle section is called the thorax, here the heart is located, as are three

pairs of legs. The wings of unmated queens are attached here as well. Two tiny

hooks on each leg enable the ant to climb vertically and upside down. Some, use

the front claws to tunnel underground. A tiny row of hairs on the front legs

serve the same purpose as those on the maxillae.

There are two pieces which make up the abdomen, the waist like petiole and an

enlarged segment which is called a gaster. The petiole is made up of one or

two movable segments with humps on top and connect the gaster to the thorax.

An ants gaster contains a crop and intestine. Some varities may also contain a

poison gland, filled with formic acid that can be sprayed at a moments notice.

This substance has proven very useful to people as it may be used as an

insecticide, antibiotic, preservative, and disinfectant. Ants were originally

the sole industrial source but it can now be artificially produced. Contact

with minimal doses of the ants product is not harmful to humans but the mass

doses of thousands can suffocate a person (Colony ?89).

Ants digest liquids only. Chewed food is moved to a pouch just below the mouth,

contractions squeeze the juices out and they are swallowed. Solids are

regurgitated, and liquids are stored in the crop. Now when the ant is hungry,

food from the crop will travel through a small valve to the intestine where it

can nourish the body. The crop lies just within the gaster and has thin

elastic walls. A full crop is large enough that this process can happen several

times before the food supply is seriously depleted.

Due to the many specialized roles in the ant community not all members are in

charge of the important task of gathering food. As a result these gatherers

must feed the other members of their community. The means employed to

accomplish this task are unique and intriguing. A hungry ant uses its antennae

and legs to tap and stroke a food gatherer on the head. Following this signal

the two ants will put their mouths together and food is passed from the crop of

the gatherer to the hungry member, this is called mutual feeding or trophallaxis.

An ant with a full crop can be distributed food to 8-10 others in this way.

And as they share their supplies one ant can feed up to 80 others(Groliers ?93).

Ants have an elaborate system of communication, which includes visual, auditory,

tactile, gustatory and olfactory signals(Groliers ?93). While eating, many

animals socialize and communicate. Few, however, are able to learn so much from

their meals. Modern science has discovered the importance of this method of

feeding. While people used to believe that ants were able to work together as

they do because they were highly intelligent insects. We now know that this is

not the case. Although they are capable of learning, ants as individuals are

not particularly intelligent at all. Secretions received from the food share

tell the ant what to do. These substances come from secretions the ants have

picked up by licking the body of the queen and her brood. Nest mates constantly

feed, lick and touch each other so these secretions are passed all around the

colony. These vital secretions act as memos in a large office building.

Because each colony has its own individual scent, they help ants to identify

each other by smell and touch. They tell an ant everything from what jobs need

doing in the nest, to communicating excitement and danger. Special glands

enable various ants to give off an alarm secretion, lay trails and attract

sister workers to a new food source, this Olfactory communication is made

possible through the release of chemicals called pheromones. So it is not

special intelligence which enables ants to communicate as they do but the

passing of and ability to react to secretions, which keep up a bond between

colony members and helps them work together.

Across the many different species there are various specialized colonies and

means of nesting. While in the majority of cases ants live in the soil or wood

or any number of natural cavities. Some nomadic army ants may form temporary

nests , or bivouacs, consisting entirely of ants themselves a living suspended

ball (A Closer Look ?75). Other ants build “carton nests” of plant tissue.

African weaver ants make their nests of living leaves bound by larval silk.

Others form a symbiotic relationship with Acatia trees eating from the plants

and guarding against other destructive insects and competitive vegetation.

Many ants also have specialized ways of obtaining food. Nomadic army ants raid

and retrieve in groups, these large species live predominantly on other

organisms. They forage en mass and are therefore able to overtake much larger

prey.

Fungus growing ants are highly specialized herbivores that ” cultivate

subterranean fungus gardens on fecal or plant-derived substrates.” These ants

live solely on fungus. “Leaf cutters” gather green leaves, which they chew and

grow fungus on.

Harvester Ants feed on seeds. Living in hot dry climates they construct

elaborate nests up to 2m below the earth devoting massive chambers entirely to

the storage of seeds, which are often topped off with a layer of gravel and sand,

as the ancient Egyptians protected their grain supplies. Harvesters often husk

collected seeds before storing(Groliers ?93).

Gatherers and herders, gather plant liquids directly from wounds and nectaries.

Others collect honeydew, a substance excreted by aphids which feed on plant

juices. The aphids are unable to digest many of the nutrients from these juices

which are beneficial to the diets of the ants. Thus, in exchange for protection

from enemies the “cow” allows the ant to feed off of its excretions.

Perhaps the most interesting however are the parasitic and slave making ants.

Two or more species may form joint nests in which the broods are separated, and

the parasitic species obtains food from the host species. In another category

called mixed colonies, the broods are mixed and cared for as one. Some

parasitic ants are permanent residents of the host colony and are so specialized

that they have lost the work caste. Here slave making may result. But perhaps

the most blatant exploitation made by one species over another found in nature

aside from we humans is the slave-making species. These raid other colonies and

steal worker pupae that they enslave to carry out the work of their colonies.

Some species, such as the ants of the Amazon are so specialized for capturing

slaves that they can not forage for food or care for their young. Without

slaves they quickly perish.

Ants are often called the most fascinating insects of all. While they can be

vastly destructive, stripping valuable trees bare in the tropics, and a general

nuisance marching through kitchens and pantries they are extremely helpful to

man as they help to clear the earth of pests like termites. Wood ants clear

forests of millions of tree-destroying insects over a single summer. They have

been here for approximately 53 million years, and 56 percent of genera

represented among the extensive Baltic amber are living today, and show no sign

of dying out soon. In our great pursuit of knowledge it is my hope that we can

derive something of value from studying the culture and life-style of the

hardest working organisms in the world. (With the exception, of course, of the

Villanova biology teachers).