National Geographic : 1959 May
on bicycles? Orellana would have turned in his grave at the sight. After half an hour or so of pedal pushing, we jumped down and hurried toward a ruined edifice half hidden in burgeoning jungle. The sky had suddenly clouded over; perhaps within those crumbling walls we could find shelter. But the ruin, an abandoned chapel, had long since lost its roof. As the downpour began, we stayed close to the decaying masonry and prayed for a quick return of blue sky. The rain was lessening when I saw some thing moving on the dank floor a yard or two away. A black creature with stiltlike legs and a pair of huge mandibles was approaching a small hole in the earth; it disappeared, fol lowed within seconds by another of its kind, and then another. Lair of the World's Largest Ant I felt a twinge of excitement. The size, the color, the form of the creatures, all were telltale. Here, in this ruin, we had come upon a lair of the world's largest ant, Dinoponera gigantea, whose wickedly stinging females are at once the rulers, warriors, reproducers, and huntresses of their jungle kingdom. To locate the nests and to observe the habits of these little-known insect behemoths was high on my list of reasons for coming to Brazil. They are found only in South Amer ica. Eighteen years earlier I had visited the Amazon Delta to observe its giant ants. Now, for the National Geographic Society, I had returned for a more careful study. As raindrops spattered from a million mois ture-laden leaves, we continued to watch the hole and the comings and goings of its in habitants. Those glistening black bodies were well in excess of an inch long, but in motion their total length, including legs and feelers, seemed closer to two inches (page 637). During previous searches we had encoun tered many single specimens of Dinoponera stalking about the floor of the jungle forest, the mata. But all attempts to follow them to their nests had failed because of the tangle of fallen logs and undergrowth into which they had invariably led us. Here the entrance to a colony lay in the open! Now the sun beat down and the jungle steamed. We quickly unpacked our gear. Then, armed with long chrome tweezers, I cautiously approached the fist-sized ant hole (page 640). Running through my mind was a comment of the late Prof. William M. Wheeler of Harvard, who in years past had sparked my interest in natural history. About giant ants he had written: "... they bite and sting with such ferocity that few observers have cared to study them at close quarters." Our plan was to seize every returning for ager, as well as any individual setting out from the hole. Thus we hoped to remove from cir culation a large part of the colony before we dug to see what lay below. Jose stood back a bit from the hole to act as lookout; he would be on the alert for any ants evading me. Unlike most other ant species, Dinoponera gigantea colonies seem to have no queen, no special soldier or worker castes, no fungus gardens, no complex tunnels and galleries. Great black females dominate each colony, capturing all food and doing all work. How reproductive duties are divided among the seemingly identical ladies is still a mystery. "On guard, senhor, one approaches!" cried Jose in Portuguese. I turned to see a heavily laden giantess bound for the hole. Securely between her jaws was a beetle, its legs still thrashing; this huntress was bringing her catch home alive. Then the chrome fingers of my 12-inch-long tweezers grasped the ant's hard thorax. Immediately the lady dropped her load and attacked the metal with vicious mandibles. Her legs braced and strained, and her abdomen contorted as she strove to escape; at the same time a hypodermic sting at the tip of her abdomen sought to pierce anything it might contact. I drew the captive close and watched droplets of venom swell from the stinger's sharp tip each time it struck metal. There was another "On guard!" from Jose; I dropped my catch into a jar and quickly Mist rises above virgin forest in the Territory of Amapa, about 100 miles north of the Equator. Said the author: "In early morning, or after a shower, the Brazilian jungle resembles a vast industrial area of smoking stacks." Most of the giant beetles collected on this National Geographic Society expedition came from the Amapa region. Nutcracker Jaws of a Giant Ant Clutch a Golden Beetle in a Death Grip The world's largest ant, Dinoponera gigantea, dwells in the Brazilian rain forest. Sting ing females dominate the smaller, weaker males and fight the colony's battles. Dino ponera's glistening black body, magnified 18 times, measures more than an inch. Her prey, a chrysomelid beetle, still lives; its brilliance will fade shortly after death. 634 ALL KODACHROMESBY PAUL A. ZAHL, NATIONALGEOGRAPHICSTAFF © N. G . S.