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 speciesare 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 thecolony. 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 veryaggressive. 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 becomeendangered.
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.