Inside the ant colony - Deborah M. Gordon

Think about all the things that need to happen

for a human settlement to thrive:

obtaining food,

building shelter,

raising children and more.

There needs to be a way to divide resources,

organize major efforts

and distribute labor efficiently.

Now imagine having to do this without any sort of planning

or higher level communication.

Welcome to the ant colony.

Ants have some of the most complex social organization

in the animal kingdom,

living in structured colonies

containing different types of members

who perform specific roles.

But although this may sound similar to some human societies,

this organization doesn't arise from any higher level decisions,

but is part of a biologically programmed cycle.

In many species,

all the winged males and winged virgin queens

from all the nearby colonies in the population

each leave from their different nests

and meet at a central place to mate,

using pheromones to guide each other to a breeding ground.

After mating, the males die off,

while females try to establish a new colony.

The few that are successful settle down in a suitable spot,

lose their wings,

and begin laying eggs,

selectively fertilizing some using stored sperm they've saved up from mating.

Fertilized eggs grow into female workers

who care for the queen and her eggs.

They will then defend the colony

and forage for food,

while unfertilized eggs grow into males

whose only job is to wait until they are ready to leave the nest

and reproduce, beginning the cycle again.

So how do worker ants decide what to do and when?

Well, they don't really.

Although they have no methods of intentional communication,

individual ants do interact with one another

through touch, sound and chemical signals.

These stimuli accomplish many things

from serving as an alarm to other ants if one is killed,

to signaling when a queen is nearing the end of her reproductive life.

But one of the most impressive collective capabilities of an ant colony

is to thoroughly and efficiently explore large areas

without any predetermined plan.

Most species of ants have little or no sense of sight

and can only smell things in their vicinity.

Combined with their lack of high level coordination,

this would seem to make them terrible explorers,

but there is an amazingly simple way

that ants maximize their searching efficiency;

by changing their movement patterns

based on individual interactions.

When two ants meet,

they sense each other by touching antennae.

If there are many ants in a small area this will happen more often

causing them to respond by moving

in more convoluted, random paths in order to search more thoroughly.

But in a larger area, with less ants, where such meetings happen less often,

they can walk in straight lines to cover more ground.

While exploring their environment in this way,

an ant may come across any number of things,

from threats or enemies, to alternate nesting sites.

And some species have another capability known as recruitment.

When one of these ants happens to find food,

it will return with it, marking its path with a chemical scent.

Other ants will then follow this pheromone trail,

renewing it each time they manage to find food and return.

Once the food in that spot is depleted,

the ants stop marking their return.

The scent dissipates and ants are no longer attracted to that path.

These seemingly crude methods of search and retrieval

are, in fact, so useful that they are applied in computer models

to obtain optimal solutions from decentralized elements,

working randomly and exchanging simple information.

This has many theoretical and practical applications,

from solving the famous traveling salesman problem,

to scheduling computing tasks and optimizing Internet searches,

to enabling groups of robots to search a minefield

or a burning building collectively, without any central control.

But you can observe these fascinatingly simple, yet effective, processes directly

through some simple experiments,

by allowing ants to enter empty spaces of various sizes

and paying attention to their behavior.

Ants may not be able to vote, hold meetings or even make any plans,

but we humans may still be able to learn something

from the way that such simple creatures

are able to function so effectively in such complex ways.