Picnic pests or ecological marvels? Ants--who have roamed the Earth since the days of the dinosaur--are expert farmers, fearsome warriors, voracious meat-eaters, and omnipresent socialites. Most of all, however, they are virtually indestructible.

• Position: Ecology

THE EXHIBIT "Ants: Hidden Worlds Revealed" showcases six colonies of live ants, each of which displays distinctive nest building and food gathering behaviors. Four of the species represented--Harvester, Carpenter, Honeypot, and Argentine--are commonly found in the U.S. The other two species, however, come from farther afield. Leaf Cutters cultivate gardens of fungus in order to ensure a steady food supply and make their home in the tropical rainforests of South America, while meat-eating Army ants migrate through parts of Africa and South and Central America in search of prey.

Each colony offers onlookers the chance to gaze inside the chambers and tunnels of the ants' nests and watch them forage for food. The most dramatic views are of the Army ants, which never before have been displayed in a large-scale exhibit. They build nests out of their own bodies by interlocking their tarsal claws to form intricate, tunnel-filled cylinders that are over three feet wide. The interior corridors and chambers of these living nests can be opened or closed according to climatic need, and the temperature can be controlled to within 1[degrees]F. Army ants also display unique foraging behaviors--they hunt by forming a fan-shaped swarm and devouring every animal in their path. In the exhibit, Army ants march across a bed of sand three times a day to prey on live crickets. The feeding show features up-close footage from two video cameras within the enclosure.

Visitors also can learn about the highly complex social structures of the various ant colonies. At the Harvester ant display, viewers will he able to discern the detailed division of labor within the colony: some worker ants husk, clean, and crack seeds, while others chew kernels into a soft pulp called "ant bread." Some store sun-dried seeds in large nest chambers or apply a chemical germicide to prevent seeds from sprouting. The Honeypot ants possess yet another specialized behavior--some individuals are designated as living refrigerants that are responsible for storing excess food in their stomachs. These "honey pots" hang from the ceilings of cool nest cavities. holding fast by their claws until their precious stores are required. As the desert's food supply dwindles seasonally, nest mates will stroke the antennae of a storage ant, causing it to regurgitate some of the "honey" into the supplicant's mouth.

"Ants" also features research by renowned scientists, including Brian Fisher, who has discovered more than 600 new species in Madagascar, including the Dracula Ant--a find that will help researchers understand the evolution of these insects from wasps. Named because of their grisly feeding habits--they cut holes into their own larvae to extract colorless insect blood--Dracula Ants have wasp-like abdomens and stinging behaviors. What follows are more detailed accounts of the six colonies on display:

Honeypot. They are found in Australia, Africa, and North and South America. The term "honeypot ant" actually describes a strategy evolved separately by a number of unrelated species in which one caste has the unique ability to store nutritious fluid for an extended period in distended abdomens--an adaptation to the constraints of the dry season. The featured Myrmecocystus mexicanus is found from Mexico to Colorado, Utah, and California. These ants live in dry, semiarid regions, such as the fringes of deserts. Queens are born with wings, but tear them off after mating by pushing them back and forth with their hind legs. Workers are small and wingless, while males are small with wings.

After the rainy season, plants produce so much nectar that there is more than enough food for these ants. During this time of plenty, some of the largest workers in the colony are fed nectar until the sweet liquid swells their abdomens, often to the size of a grape. These individuals literally are the "honey pots" that hang, like utensils in some kitchens, from the ceilings of nest cavities, holding fast by their claws until their precious stores are required. As the desert's food supply dwindles seasonally, nest mates will stroke the antennae of a storage ant, and it will regurgitate some of the "honey" into the supplicant's mouth. In a sense, Honeypot ants have evolved their...