How Do Termites Access the Nutrients Containing Cellulose?
WouterTermites are able to use the nutrients contained in cellulose to maintain their health. They eat dead and living trees and woody materials, as well as a variety of other materials.
They ingest cellulose through their digestive system. The termite digestive system is divided into five segments: the foregut, midgut, hindgut, colon and rectum. Each of these segments contains symbiotic microorganisms. Some bacteria are considered facultative, but others are thought to play a role in the breakdown of cellulose.
The hindgut of termites contains symbiotic protozoa. These organisms produce enzymes to break down cellulose and other by-products of the breakdown of wood. The protozoa provide the necessary enzymes for lower termites to complete the digestion of cellulose. In addition to producing enzymes, the protozoa also provide the host termite with a source of energy.
When a termite molts, it loses the ability to produce protozoa. However, the symbiotic relationship benefits the host termite’s nitrogen metabolism and carbon metabolism. In addition, protozoa may be responsible for the breakdown of lignin, a molecule that gives wood its tensile strength.
Interestingly, there is evidence that protozoa can also degrade acetate, a substance that is believed to be used by the termite for energy. Hungate (1939 and 1943) studied Zootermopsis and found that the hindgut of this termite produced acetate. But he attributed the activity to indigenous microorganisms.
Other researchers have found that the bacteria in the three-way symbiosis can take nitrogen from the air and turn it into a nutrient. Some have suggested that this activity might be useful to higher termites as an energy source.
