Termite is the common name for certain groups of small insects that live in large colonies. Termites feed primarily on cellulose and lignin, substances found in the cell walls of plants. These substances make up the key ingredients in all wood and wood products. Termites inhabit many parts of the world, especially in warm, humid regions.
Termites somewhat resemble ants. But ants have narrow waists and elbowed antennae, while termites have thick waists and antennae that resemble strings of beads. Termites cannot digest cellulose directly, so many rely on bacteria and protozoa living in their intestines. These microscopic organisms supply most of the enzymes needed for cellulose digestion. Enzymes are substances that speed up chemical reactions.
Termites play important roles in the environment. For example, they help break down and recycle dead wood and other plant tissues. They also provide food for such animals as ants, anteaters, and slender blind snakes. Yet termites rank among the most damaging pests for human beings. They attack wood in homes, fences, and other valuable structures. They also damage such agricultural crops as potatoes and sugar cane.
The termite colony
forms a large extended family. Within the family, various castes (groups) have different functions.
The worker caste makes up the largest group. It consists of small, blind, wingless individuals with soft bodies. Depending on the colony, the worker caste can number in the hundreds, thousands, or even millions. Workers perform all of the hard labor in the colony. They clean, maintain, and repair the nest; gather food and water; care for the young; and construct new tunnels and chambers in the nest as the colony grows.
Members of the soldier caste grow larger than do the workers, but they are fewer in number. These blind, wingless insects have large heads and often powerful jaws. They guard the nest site and protect it from attacks by ants or other invaders. Soldiers of some species lack jaws. Instead, they have a large head gland that shoots chemicals through a nozzle at the front of the head. Most such chemicals form a sticky substance that can slow down smaller enemies. The worker termites care for the soldiers by feeding and grooming them.
The reproductive caste includes a king and queen, the parents of the colony. A queen can lay large numbers of eggs. Once the king and queen have produced worker offspring, the workers then feed the parent couple. Some termite colonies have a few other reproductives that share egg laying duties. Each year, every mature colony develops a group of young winged reproductives that swarm from the nest for a short mating flight. After the flight, their delicate wings break off, and the new kings and queens set out to start new colonies. Reproductives are the only fully developed adult termites.
Termite colonies typically produce both males and females in every caste. In other insect colonies, such as those of ants or bees, males serve only to mate.
Kinds of termites.
Hundreds of different termite species exist. Scientists may divide them into two main groups: (1) those that live within wood and (2) those that tunnel and nest in soil. Wood-dwelling types often nest only in rotten wood, damp wood, or dry wood. Their colonies remain rather small and persist only as long as the food source lasts. All wood-dwelling termites produce distinctive waste pellets. For people, these pellets often act as an early warning sign of termite activity.
Soil-dwelling termites construct underground nests. If a particular source of food runs out, these species can tunnel through the soil to find new food sources. Such colonies usually live much longer than do wood-dwelling colonies. Some may survive well over 70 years. Underground colonies also grow much larger, often containing several million individuals.
Soil-dwelling termites of North America and Europe commonly invade wooden structures above the ground. They do this by building earthen tubes that serve as protective tunnels between the nest and their food source. Such tubes warn people of a termite invasion.
In various warm regions, especially in Africa and Australia, other soil-dwelling species build nest mounds up to 20 feet (6 meters) tall. These complex mounds have thick outer walls and numerous inner chambers and tunnels. The king and queen live in a chamber deep inside the mound. When reproducing, the queen’s abdomen grows large enough to hold many thousands of eggs. She then lays these eggs at the rate of several thousand a day. Worker termites carry the eggs away to specially constructed cells in the nest. There the workers care for the young as they hatch from the eggs.
Certain mound-building termites do not have bacteria or protozoa in their intestines to help digest cellulose. Instead, these insects rely for digestion on a fungus that they cultivate in underground fungus gardens. To create these gardens, workers first collect plant material and mix it with saliva and their own waste products to form a paste. They then inject the paste with fungus spores (reproductive cells) and place it in certain chambers in the nest. As the fungus gardens grow, the termites feed on digestible structures produced by the fungi.
Termite control.
To protect buildings from termite damage, people should use brick, stone, or concrete foundations. All wood less than 18 inches (46 centimeters) from the ground should receive extensive treatment with wood preservatives. Such preservatives create an environment poisonous to termites. People also may use pesticides and other chemicals to fight these insects. One method for controlling soil-dwelling termites involves planting underground baits. The baits typically dispense slow-acting chemicals that disrupt the insects’ growth and development.
