Today, modern termites are one of the world's most pervasive and successful insect groups, with about 2,300 known species, mostly in tropical settings, busily at work chewing wood or other plant fiber that protozoa help to digest. They have important ecological roles, helping to create habitat, build soil fertility, recycle nutrients and serve as food for many predators. As a social species similar to ants, some colonies can have 20 million individual insects. And they also cause massive amounts of damage every year to wood structures in much of the world.
Their dependence on these protozoa is now well understood, and the process isn't always pretty.
Somewhere on the evolutionary scale the termites began producing a liquid that contained protozoa that they would excrete. The termite offspring in turn consume the feces and thereby gain the protozoa in their digestive systems.
It took time for all of this to get worked out, the study indicated. The successful establishment of protozoa in the termites required them to withstand the chemical and physical conditions inside the alimentary tract, use the gut contents as a food source, cause no damage to the host and be carried through successive stages and generations.
But by the different species each specializing at what they do best the termite eats, the protozoa digests the two groups have both had extraordinary evolutionary success.
"The relationship between termites and protozoa is very close and has been stabilized now for a very long time because of its obvious value," Poinar said. "It's exciting to understand that this classic example of mutualism has been going on now for at least 100 million years."
As well as outlining this age-old example of mutualism, the new study revealed 10 new fossil flagellate species of protozoa, a new species of termite, a new genus of fossil amoeba and 14 additional trophic and encysted protist stages.'/>"/>
|Contact: George Poinar|
Oregon State University