National Geographic : 1988 Dec
D Marauder ants the large and the small of it like some fairy-tale giantess towering over a diminutive Jack, an ant queen dwarfs a tiny worker. Both, amazingly, are from the same tropical Asian species, Pheidologetonsilenus. Exhibiting a trait known as polymorphism, this species and the closely related marauder ant (P. diversus) have evolved with different physical castes, each specializing in its own social tasks. Most of the workers, called minors, left, are just three millimeters long (a tenth of an inch). Some are intermediate size workers called medias, and a few are ferocious looking majors, armed with strong mandibles. The largest caste is the queen seen here. Her body weight can be a thousand times that of a minor. The queen plays a privileged role in the all-female ant society. She alone is fertile; males exist only to fertilize her; then they die. All the workers in her realm are her daughters, who feed and tend her and her eggs con stantly. She occasionally spawns new queens, who fly off to mate and start new colonies. Marauder ants forage for food in an organized system that Napoleon would have envied. They carefully construct trunk trails up to three centimeters (an inch) wide. This is the artery through which all food flows to the nest. From these trails, tens of thousands of ants branch off in columns that can expand into fan-shaped raiding parties up to four meters across. Their prey worms, centipedes, even frogs are overwhelmed by sheer num bers and are crushed between the majors' powerful mandibles. Vegetable matter, mostly seeds, also enriches their diet. "I have seen trunk trails as long as 300 feet [90 meters]," scientist Mark W. Moffett reported in the August 1986 NATIONAL GEOGRAPHIC. "Thousands of individuals seemed to merge into a single dynamic pattern. It was as if all the ants had united to form one great living creature.... Then this vision would dissolve, and the individuals would reappear, their labors finely coordinated, the different castes intricately apportioning the day's tasks."