The Bug Box: Lichens

U.S. Forest Service


This bug is creeping around your property. He may be friend or foe.

Name: Lichens

Alias: Lichens. These organisms live in many different places and occur all over the world. They are common in our area and may be found on trees, fences, rocks and other places. All lichens are made up of a fungal partner and either an algal or a cyanobacterium partner, or both, generally in a symbiotic relationship. The resulting structure is called a thallus. The fungus obtains water and minerals from the air and the material on which it grows. The alga provides carbohydrates and vitamins. Some fix their own nitrogen, while most obtain nitrogen from bird excrement, organic debris or plant leachates. They come in several different colors including gray, green yellow, black, red and orange. The shapes they form run from rather nondescript to delicate 3-D patterns and shapes. Some even have leaf-like fronds. Lichens growing on trees indicate that the air in that location is very pure.

Crimes: Although lichens grow on tree bark, they are not parasitic and do not harm trees. Lichens are one of the good guys.

Redeeming Qualities: Lichens are useful as food, medicine, for making dyes, in perfume manufacture, as decorations and in science. In Japan, lichens are considered a delicacy and eaten as a soup or in salads. Some believe that the lichen Lecanora esculenta was the original biblical manna, as it has the habit of coming loose from its substrate and being blown around in the wind. In the northern tundra reindeer and caribou eat lichens. Eskimos and Lapps both harvest and store these lichens as part of the winter feed for their animals. Deer have an enzyme called lichenase that helps them to digest the lichens they eat. Research is active into the use of several lichen products as antiviral and antifungal agents.

Sentence: Observe and enjoy.

For more information on dangerous and beneficial bugs, call agent Wayne Jones at the Bonneville County Extension Office at 208-529-1390.