Leafcutter Ants
of Cloudbridge
When
hiking the forest trails of the Cloudbridge Reserve it is common to see
small trails with many busy ants carrying leaf material from trees to
their nest. The ecology and social dynamics of the leaf-cutter ants
(Atta cephalotes) is fascinating.
 Leaf-cutter ants
tear portions of leaves from trees with their scissor-like jaws and
carry the leaves to their nest. Each ant can carry 50 times its own
weight. They leave an invisible scent on the trails they use in order
to
find their way back because sometimes they travel several hundred yards
away
from the nest. Once in the nest they chew the leaves into a pulp-like
material,
which soon sprouts a fungus and the ants grow and cultivate “fungus
gardens”.
The fungus, in turn, is food for the ants. What is left over is organic
matter
in the form of leaves, fungus, and waste, which helps to add nutrients
to
the soil. The nests can be 3,000 to 4,500 square feet and may be 8 feet
or
more deep. Thousands of chambers will contain the fungus gardens and
the
nest can house millions of ants.
A
colony
of leaf-cutting ants is comprised of several castes. Two of the castes
include queens and drones, (males, who hatch from unfertilized eggs and
die shortly after mating with the queen). Only queens and drones can
mate
and queens and drones are the only ants in the colony that can fly.
Most
colonies have only one queen, but sometimes there are two or three,
especially
in large colonies. Other castes include minors ('nurses'), medians
('workers'),
and majors ('soldiers'). These are all essentially workers, but they
have
specialized jobs and are different sizes.
The
queen's main responsibility is to lay eggs and develop new colonies.
When a queen wants to start a new colony, she takes a piece of fungal
hyphae from one of the gardens and tucks it into a small area in her
head. She then flies away in search of a drone. When she finds a drone
she mates with it and then looks for a suitable spot to start a colony.
She then digs her nest and begins to lay her eggs. A queen is capable
of laying thousands of eggs every day. The ants go right to work once
hatched. The workers, which are the largest caste in the colony, neatly
cut off pieces of leaves off the trees
(see picture) and take them back to the nest. Once workers deposit the
leaves,
the nurse ants chew them up and lay them down. The nurses also
tend
to the larvae and eggs in the colony. The large soldiers defend the
colony
and provide protection to the workers from enemy ants and predators.
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