National Geographic : 2011 May
• messages. ey release more pheromones into the air to broadcast signals quickly and widely. ey even display symbolic behavior: To warn of an approaching enemy, for instance, they jerk their bodies in a kind of ritualized ght. Scientists have likened weaver ant commu- nication to a type of language with primitive syntax. Urban planners examine the organiza- tion of ant societies. Mathematicians draw upon analyses of ant behavior to devise parallel com- puting formulas (where multiple problems are solved simultaneously). Ants serve as models in all kinds of studies aimed at guring out how big, complex jobs get done with small parts and a minimum of instructions. Here is how a weaver ant nest-construction project gets under way. A single worker stands on a leaf and reaches to grasp the edge of another leaf nearby. If the span is too great, a second worker climbs over the rst, and the bottom ant grasps the newcom- er by its wire-thin waist and holds it out closer to the goal. Still not enough? A third ant clambers over the rst two and is li ed out farther yet. Ant by ant, a living chain grows into thin air like the arm of a construction crane. Once the dis- tant leaf is grabbed, the squad pulls in unison, o en with nest mates that have formed parallel chains and reinforcing cross-links, to draw the leaves' edges together. Workers begin to array themselves like live staples along the seam be- tween the leaves, legs holding on to one edge, jaws gripping the other. And then? ey wait. As evening comes on and the humidity rises, more workers arrive from nearby nests. ey're carrying larvae that are about to enter the pupal stage and metamorphose into adults. Larvae of other ant species spin individual protective cocoons of silk. Oecophylla larvae do- nate their silk to the colony. Straddling the leaf seam, an adult uses its antennae to tap the head of the larva held in its jaws, telling it to extrude silk from its salivary glands. A worker's oper- ating manual would read: Swing head to one side. Tappity-tap larva. Dab glob of its silk onto leaf. Swing head opposite way, drawing thread across to other leaf. Keep tappity-tapping larva. Dab next glob there. Step forward. Repeat pro- cedure. When nished, move on to other tasks. If you're close enough to witness this use of juveniles as sewing tools, some workers are probably going to be biting you, having caught your motion with their keen eyes, sensed the odors in your breath, or felt movement when you brushed a branch. When you're really close, an agitated throng coats the nearest plant parts like bristling fur, each ant li ing its body high on four legs, raising its gaster---the largest and Save the queen! If disturbed by an intruder, minor workers---the caste of ants that tends to her majesty---envelop the matriarch (below, in Australia) to protect her from harm. The queen is the grower of the superorganism, producing tens of millions of eggs over her life span of several years.