es and hoards of workers fan out from the bivouac in all directions. Soon, one or more columns form and begin to search for food. The workers lay down a pheromone trail for others to follow while the soldiers guard the perimeter of the trail. Workers form numerous columns; changing positions behind the advancing hoards of ants—flushing out large numbers of prey (arthropods, small reptiles and rodents). The prey is stung, killed and transported to the rear as food for the larvae. At the end of the day the cluster is reformed. When the food supply is depleted around the area of the bivouac, the colony relocates.
Some colonies of army ants may number as high as one million individuals. Because of the spectacular size of their colonies and ‘raiding’ nature of these insects, they have been used repeatedly by the motion picture industry. Actually army ants pose no threat to humans or other large animals.
The authors recently had the opportunity to observe army ant behavior in Costa Rica. One morning we were walking down a dirt road with several students collecting insects. Collecting was not that good but suddenly hoards of insects, spiders and even a few scorpions and lizards started pouring out from the underbrush across the road we were on. After a few moments of excellent collecting, we decided to investigate the reason for this windfall. And, as you might suspect, there was a column of army ants moving through a gully to the side of the road. Of course all the animals in its path were attempting to flee. On the following evening a column of army ants raided the students' cabin. The students were not awakened, but the following morning they were very disappointed to see that the army ants had stolen most of the several thousand insects they had collected and mounted on pins over the past week. Shortly thereafter, I decided to test the reports that army ants pose no threat to humans. There was a column moving through our pension grounds--so I placed my foot directly in their path. They merely ignored this obstacle and marched over and around it.
While the army ants are primarily found in the New World tropics the driver ants are found in the tropics of Africa. Both types are very similar as far as their behavior and biology is concerned. One distinct difference is that while large colonies of army ants may number one million colonies of driver ants can reach 200 million. With such huge numbers they present more of a threat to humans and other animals. There have been human deaths recorded from the raids of these critters (mostly infants). In these cases death has typically occurred from suffocation as a result of the ants entering and filling the lungs.
The mating behavior of these ants is especially strange. The males are to drawn to the foraging columns supposedly looking for a mate. Instead of finding a queen the sterile workers quickly swarm the males and immediately tear their wings off. Then they carry them off and basically imprison them until a potential new queen is available.
Bullet Ants. This ant is primarily found in rainforests ranging from Nicaragua to Paraguay and Australia. This huge (1 inch) beast is called the bullet ant because its sting feels like being shot by a bullet. On the Schmidt Sting Index bullet ants rate as the number one most painful sting found in the arthropods. When defending their nest they swarm out, release a strong odor and stridulate an audible sound (said to sound like a shriek) and then grab and impale their intruder. In Central-South America they are referred to as the 24-hour ant, referring to the pain described as “of burning, throbbing, all consuming pain” that may last a day or more.
A one-inch Costa Rican bullet ant.
As with many other arthropods bullet ants play a ceremonial role in some tribes of the rainforests. The Satere-Mawe people of Brazil use this ant in the right of passage of boys into manhood. In this case live bullet ants are woven into a sleeve made of leaves with the stingers pointing inward. Once the sleeve is place on the arm the goal is to leave it on for 10 m