How Do Termites Digest Wood?
Termites are small, ant-like insects that eat nearly anything made of wood. Oddly enough, they cannot digest the wood they eat. Termites have formed a remarkable partnership with microbes which live in the termites’ intestines.
The termites chew and swallow the wood, and the microbes digest it, changing the wood into food that both the termite and the microbes can use. Forest termites serve a useful purpose by cleaning away dead wood. But termites that live near man cause much damage by destroying houses and barns.
Termites depend upon these microbes in their digestive tract to digest the complex sugars in wood into simpler molecules that they can use for food. Cellulose is a major sugar in wood and it is broken down in the hindgut of the termite by microbes into molecules called short-chain fatty acids. Acetic acid is one of these acids. You know it better as vinegar.
The termite’s cells use these acids as nourishment, just like our cells do. The microbes in our digestive tract break down our food into these same acids to feed our tissues. The termite’s microbes also produce gasses during this breakdown process. Methane gas is a major product and termites are a large source of methane in our atmosphere. Methane is a more potent greenhouse gas than carbon dioxide.
No one microbe in the termite gut can do the job. A whole community of microorganisms is necessary. These microbes belong to three groups, bacteria, archaea and protozoans. Organisms that live with one another for long periods of time are said to live in symbiosis. The symbioses in the termite gut are often beneficial to both partners and so are called a mutuality relationship.
Sometimes neither partner can live without the other, so the relationship is called an obligate symbiosis. The protozoans and the bacteria and archeae that live inside them often depend upon one another and cannot live without each other, so they are an example of an obligate symbiosis. The bacteria and archaea that live inside their partner are also called endosymbionts, “endo-” meaning “within.”