Behavior of Ants
Division of Labor
Ant colonies are grossly divided into queens, males, and
workers. The job of the queen is to lay eggs. The males generally do nothing
for the colony. They wander around accepting food from the workers until
the time comes for mating. They die almost immediately after mating. Workers
are generally sterile females. They have a variety of tasks to perform
for the colony ranging from foragers, defenders, brood feeders, food preparers,
caretakers of the queen and nest construction, among other things. The
size of the ant in the colony is often different according to the task
the ant needs to perform. The queen is often the largest; brood keepers
are the smallest. Soldiers are large, and foragers are smaller.
When ants specialize, they help the colony survive in a number of ways.
For example, foragers are constantly exposed to danger while out on the
hunt. A small percentage of the colony acts as foragers though, so the
majority of the colony is safely tucked away in the nest. The foragers
are sacrificing for the majority of the colony, which means that the colony
will probably survive longer. If every ant in the colony had to forage,
then every individual would be exposed to great dangers. Interestingly,
duties are often assigned according to the age of the ant. The younger
ants are closer to the queen, taking care of her and the brood, while
the older ants are usually delegated the more dangerous tasks of foraging
The overriding goal of every foraging ant is to spend the
least amount of energy to obtain and deliver the greatest food value to
the colony. As long as enough foragers are successful, the colony can
maintain the energy flow to continue reproducing indefinitely.
One major deciding factor as to foraging technique takes into account
the external dangers presented to ants while foraging. They are constantly
under attack by predators and competitors. When an ant is lost to predation
or injury, the whole colony loses a small energy packet. Predators may
influence whether a colony hunts with packs of ants going off at a time
or if the colony uses individuals to hunt on their own. Will they hunt
out in the open or will they hide under some sort of canopy?
If competition is a problem, ants may expend a larger amount of energy
to retrieve a food source quickly, rather than to go slowly and allow
other colonies to take the food.
Temperature and humidity are two important environmental factors effecting
foraging. Desert ants are adapted to higher temperatures and lower humidity,
while cold weather species do better in higher humidity, cooler temperatures.
Some ants forage before sunrise and after sunset when the temperatures
are not too hot. Others forage only after sunrise and before sunset to
take advantage of the warmer temperatures. Some ants may forage at unseemly
times of the day to avoid predators. Foraging may be controlled by the
time of availability of the food source. High humidity seems to present
a higher temperature window as to when ants will forage. Most ants will
not forage during or shortly after a rainfall.
When foraging, ants seek a variety of materials depending on the needs
of their colony. At different times, the colony may need protein or may
need carbohydrates. Ants can be predators, omnivorous, seed specialists,
or fungus gardeners. There are no known ants that actually eat leaves,
but there are ants that use leaves for different purposes.