810-Lancast«r Farming, Saturday, March 9,1985 Kidnapping, slave ly, routine to WASHINGTON - Slavery may have been abolished in most places, but not in the ant world. Certain species of ants live solely on slave labor, enslaving other ants for life. A typical colony of 3,000 western slave-making ants may have more than 6,000 slaves working for it. Slave ants forage for food, regurgitate food to their hosts, groom and feed the larvae and queen ant, and defend the nest against attack from other insects. If the colony moves to a different location, the slaves carry their masters, one by one, to their new home. “The slaves do all the work. They run the colony. It literally belongs to them,’’ explains psychologist Howard Topoff, who has spent several summers in an Arizona mountain desert watching the western slave-making ant, Polyergus breviceps, force ants of a related species, Formica gnava, into a life of slavery. STEAL YOUNG FROM NESTS The slave-makers put the ants in bondage by raiding Formica nests and stealing their young, the papae. Slavery among the ants, one of the most unusual forms of social behavior to have evolved, is carried on in fewer than 100 of the 12,000 to 14,000 species of ants on Earth. Slave-making ants are found primarily in Europe and North America, including nearly every region of the United States. Slave raids may be happening in your own back yard. First the scouts go out. In the slave states of the high desert, ■\W BLACK feuow BLUE BROWN LEWIS CARROLL U/AS 7NE NAME SIGNSO TO SEVERAL FAMOUS STOWBS FOR CHILD. REH LEIA/JS CARROLL USAS ONLY A PEN NAME. N/SREAL NAM£ U/AS CHARLES 0003 . SON, A MATHEMATICS PRO FESSOR AT OXFORD UNIVER SITY/N ENGLAND*. N£ U/ROTE * ALICE'S ADVENTURES IN WON DERLAND* ANDTNROO6H THE LOOKING-GLASS'!HE U/AS MORE FAMOUS FOR HIS STORIES THAN AS A MATHEMATICIAN. some ants 4,800 feet up in the Chiricahua Mountains of southeastern Arizona, scout ants look for target nests under rocks and leaf litter near mesquite, cat’s claw, snakeweed, prickly-pear cactus, and other shrubs. The scouts are always after the same Formica species. The successful scout heads straight back to its own colony to recruit raiders. It arouses the ants through both tactile and chemical interactions. Thousands of excited red ants start swarming. All of a sudden, very abruptly, they’re on the march. The advancing army may number 2,000 to 2,500, a moving column about three feet wide and up to 16 feet long. “It lodes like the approach to the George Washington Bridge in New York in rush hour - everyone trying to get into a different lane,” says Topoff, a professor at Hunter College in New York' City. Typically the ants are on the march for about a half-hour. The raid itself is generally bloodless. “There’s very little killing. Polyergus ants use chemical warfare instead. It’s very ritualized,” Topoff explains. SPRAY CONFUSES VICTIMS The raiding party sprays the target nest with a chemical, known as a propaganda pheromone, that agitates and confuses the Formica adult workers and queen and forces them to bolt out of their nest and scatter in every direction. The fleeing ants try to escape with their brood, but most of the young get left behind. The raiders pile in and within ORAW6E PEACH LT BROWS) LT. BLUE LT.6R6EM 0 ♦ m Slave-making red ants carry off a pupa during a raid on the next of the related ant species in an Arizona desert. The kidnapped ant becomes the slave for the life of the master species, Polyergus breviceps, which depends on slave labor and survival. The dominant ants, no more than a half-inch long, may take 2,000 pupae in one raid. seconds snatch the pupae. “If it’s a good haul, they come away with about 2,000. They may even go back for a second round, and get as many as 4,500,” Topoff says. The fate of the captured ants is f* either to be eaten (more than half are used for food) or to be raised as slaves. In a good season, a Polyergus colony may steal 20,000 to 30,000 pupae. Slave raids are conducted MRRCHhU fiuca 3-2/-8S ./ * * throughout the spring and sum mer, usually during the cooler part of the day; in the high desert, the raids take place between midaf temoon and sundown. )R£ MQP MTTa& ' Wl A** jr s,.*W - A - 4# (Turn to Page B 12) '£SS
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