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   The Baker Endowment
   Calendar of Events
   Things to Expect & Do
   Ants: The Good, the
          Bad, and the Zany
   Barnyard Trivia
   Landscaping with Good
          Taste
   Word Wise
   Speaking of Spinach
   Spinach Recipes
   Beautiful Brittlebrush
   Computer Corner
   Invasive Plant Notes
   Book Review
   Harvest Time Puzzle
   Go Native with
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   Can You Identify This
          Plant?
   Homing in on Jojoba
   The Plant Vampires
   Of Friendships &
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Master Gardener Journal  


S P E C I A L   F E A T U R E



Ants: The Good, the Bad, and the Zany

by Sue Hakala,
Master Gardener


A new ant colony begins when winged reproducing queens and males fly away from the colony where they were hatched to establish a new colony. This activity generally takes place on a warm sunny day following a rain, when temperature and humidity are right. Timing of the flight is specific to individual species, with some migrating as precisely as from 10 a.m. to 11 a.m. Migrating ants don't fly a great distance-maybe only 50 feet-attracted by specialized pheromones that call mates together.

The potential queen can mate several times, storing enough sperm packets within her body to last a lifetime. Males then either die or are eaten by predators. After mating the queen rubs off her wings and digs to get underground quickly to avoid predators. Out of 1,000 new queens, only two or three will survive to create a successful colony.

The new queen lays her eggs, and once they hatch she tends and cleans the young. She feeds them utilizing fat stored in her flight muscles. Once the first set of young goes through their complete metamorphosis from egg to larva to pupae to adult, the worker daughters take over and the queen begins to lay more eggs.

It is the job of worker ants to enlarge the nest, carrying the dirt to the surface in their jaws. Ant nests are generally 8 to 24 inches underground, but in hot desert climates they may go deeper to where the soil is cool. The mound serves to maintain the temperature of the nest. The higher the mound the more heat is brought into the nest. In very hot weather other holes may be opened to let some of the heat out. Disturbing the mound with a careless foot quickly may change the temperature within the nest, jeopardizing the eggs. In cool weather ants may sunbathe at the entrance, then return to the nest to give out the heat stored in their bodies.

WHAT DO ANTS EAT?
Depending on the species, ants may eat sugars from plant juices, sweet liquids, protein from insects and animals, seeds, or fungus.

Leaf-cutting ants in Central and South America gather leaf bits and partially chew them to release nutrients. They then plant these leaf bits for fungus to grow on. Leaf-cutter ants get only 9 percent of their total nutritional needs from the fungus; the rest comes from the leaf sap collected while cutting the leaves. Any time toxic leaves find their way into the nest for the fungus, a chemical signal is emitted that alerts other ants to the danger and they then spread the word to stop gathering those leaves.

Some species of ants collect seeds. "Miller" ants, specialized ants with large heads and jaws, are needed to grind and remove seed coats. They hang out at the nest opening, and accept seeds for processing.

Other ants send out "scouts" that scurry around looking for a food source, mostly in the cool parts of the day. Any time they locate food that they aren't able to carry back to the mound themselves, they communicate this information to the others, and "soldier" ants with larger, stronger jaws show up to assist by biting off pieces for other ants to carry. Then the familiar conga line forms, going to and from the nest. Ants can carry 50 times their own weight, which would be equivalent to a human being lifting an elephant.

Some ant species farm aphids. The ants tap the aphids with their antenna to let them know they would like some honeydew. The ants carry the "honey" back to the nest in their mouths and feed others. These ants will carry off aphid eggs and winter over with them to have a start on a new crop of aphids in the spring.

The western United States and Mexico are home to a species of ant that has specially adapted workers who store nectar within their bodies to feed the colony later. These ants sometimes swell with nectar until they are too large to leave the nest. When the weather gets very hot and the colony stays at home, it gets its nourishment from these living honey pots.

DO ANTS FIGHT?
Yes, like humans they fight and enslave their own kind. They raid other nests in their territory and are willing to fight to the death. Some species maintain patrols at the edge of their territory that watch for intruders. A pheromone alarm summons others for defense. They surround the enemy, sting it with protein-digesting venom, squirt formic acid to paralyze it, and bite it with powerful jaws. If the battle isn't going well an alarm alerts the rest of the colony to take some eggs, larvae, and even the queen to a safer location. When ants swarm over human beings, they inject histamine that is irritating and causes us to itch.

Ant enemies include insects, spiders, birds, and mammals, as well as man. Small mites live on some ants, stealing food from them as it is passed to other ants. Invading flies will sometimes trick worker ants with chemical scents that allow entry to the colony so they can lay eggs on the queen. The newborn flies kill the queen, and then are cared for by the workers.

Slave-maker ants have large, strong mandibles that are great for fighting, but are too big to allow them to feed themselves. They raid nearby colonies, taking larvae and pupae to rear. When grown, these captives will fill the needs of the slave-maker ants.

HOW DO ANTS FIND THEIR WAY HOME?
Most ants forage close to home. They don't rely on pheromone trails, since the trails don't last very long. Instead, they use multi-faceted eyes to see landmarks or the sun's position. Ants use regular foraging paths that they keep free of obstructions and return to places where they have found food before.

SO WHAT GOOD ARE ANTS?
They eat pests harmful to crops and orchards. They destroy garden pests, killing small larvae and culling aphids before they can destroy the plant they are on. Ants kill 40 percent of newly hatched plant-feeding bugs and 30 percent of flies, making them more effective than some pesticides. One species of ants destroys up to 12,000 larvae a day!

Ants also pollinate while feeding on nectar, and their tunnels allow air to circulate in the ground, which is beneficial to the soil and plant roots. They are useful in creating a stable ecosystem.

Some ants do particularly strange things. "Rafting" ants (very small red ones) swarm from their mound in my yard at sunset every day, and during the next few hours they join together in a low birdbath in perfectly round quarter-size groupings. They float there until morning, when I dump them out and refill the bowl. I can't tell what they're doing other than just hanging out and trying to keep cool on a hot desert night. Not a bad idea, really.


Maricopa County Master Gardener Volunteer Information
Last Updated October 4, 2003
Author: Lucy K. Bradley, Extension Agent Urban Horticulture, University of Arizona Cooperative Extension, Maricopa County
© 1997 The University of Arizona, College of Agriculture and Life Sciences, Cooperative Extension in Maricopa County
Comments to Maricopa-hort@ag.arizona.edu 4341 E. Broadway Road, Phoenix, AZ 85040,
Voice: (602) 470-8086 ext. 301, Fax (602) 470-8092