Ants Play Red Light, Green Light
Scientists have long known that ants lay down scent trails, using pheromones, to mark the trail to goodies for their nest mates. While this is an efficient method for food gathering, it has been found that when a food source is exhausted, the ants leave a "Do not enter" sign that saves fellow ants from wasting time on this trail.
While researchers were studying ant trails in the lab, they began to notice that some ants would make a U-turn about 15 ant-lengths before the fork in the trail that led to an exhausted food source. The researchers, thus, believed that the ants can produce a repellant pheromone. So they set up a special test track that divided into two paths. Each ended at a feeder, but only one of the feeders had food. Each pathway had a removable paper cover. After the ants had used it for awhile, establishing their trails, researchers moved the paper from the trail with no food to a new forked track. The trail that led to food received only a clean piece of paper. When the ants used the new experimental setup, 70 percent of them avoided the no-food trail.
Scientists had long rejected claims that ants foraged with this level of efficiency. However, why not admit that this efficiency, which had no reason to evolve, was intelligently created?