Grass Clippers
Harvester ants are medium-sized ants that
live in temperate North America. The name harvester ant comes from the ants'
habit of cutting little pieces of grass. They use these grass clippings to
build large nest mounds. Two of the most common harvester ant species are
the western (red) harvester ant and the Texas harvester ant.
Location, Location, Location!
There are 26 species of harvester ants in
the United States. Except for one species, most are found west of the Mississippi
River. Harvester ants usually live in dry environments.
They like to build their nests in
exposed areas. Some nests are quite large. They may be 4.6
m deep and may be home to up to 10,000 harvester ants.
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Harvester ants use bits of grass and plants to build huge nest mounds. Some
are as wide as 70cm across!
©M. Durham/GLOBIO.org Harvester ant nests are easy to spot. A mound
up to 70
cm across made of clipped grass and plant stems marks the site of the nest.
Inside the nest are several separate storage areas called granaries.
The granaries hold seeds that the ants have collected and are saving for future
meals. Occasionally, the harvester ants build their nests in places that create
problems for humans, like golf courses, parks, or people's lawns.
Hitting the Dinner Trail
The main sources of food for harvester ants
are the seeds of different types of grasses. They also eat the bodies of insects and
spiders. Worker ants collect seeds by traveling over well-developed trails
that can extend 50-60
km from the nest!
A harvester ant near Kerman, Iran, travels over well-established trails.
It is returning to its nest with a seed it has collected. The seed will be
stored in the nest’s granary.
©M. Moffett/Minden Pictures Ouch! That Stings!
Harvester ants have a strong sting, which
they use to defend the colony.
When disturbed, the ants come rushing out of the nest. They pinch intruders
with their mandibles and
then sting them with small stingers on their abdomens.
An Enemy in “Armor”
Harvester ants have a strong sting that they use against intruders when
defending their colony. They also use their mandibles to pinch their attackers.
©M. Durham/GLOBIO.org Harvester ants are very aggressive.
But the horned lizard, or "horned toad," is a reptile with the perfect
defense against them. Horned lizards have tough scales that act like armor
and protect them from even the worst ant attacks. The ants can sting and sting
and a horned lizard won’t feel a thing. This is bad news for harvester
ants. Horned lizards feed almost entirely on harvester ants. In areas where
harvester ants are disappearing, horned lizards have become endangered.
Astro Ants
In 2003, the space shuttle Columbia carried the first ants – harvester
ants – into space.
©NASA Harvester ants became famous in 2003 for
being the first ants to travel into space. They were aboard a 16-day flight
of the NASA space shuttle, Columbia. The ants were part of an experiment
to observe and study the effects of space flight and a weightless environment
on the tunneling behavior of ants.
If your class would like to study harvester ants like the shuttle astronauts
did, ask your teacher to email GLOBIO for more information.