Earthworms feed on toxins which come from dirt, rotten roots and dead leaves. This makes them detritivores, a class of organisms which also include bacteria, fungi and bugs and are responsible with turning the dead matter into something which helps plants grow. Researchers from Imperial College London have managed to discover how earthworms survive in such conditions. The paper was published in the journal Nature Communications.
The study has revealed the secret lies in a class of molecules known as drilodefensins which are able to fight the toxicity of polyphenols. Polyphenols is another class of molecules that is produced by plants. They protect the plants from UV rays, function as infection-shielding antioxidants and give color to the plants. Unfortunately these molecules are toxic for herbivores in order to protect the plants from being eaten.
Luckily earthworms are capable of counterattacking the toxicity of polyphenols. Researchers discovered that if a worm’s diet includes more polyphenols the amount of drilodefensins produced will also increase. The lead author of the study Jake Bundy explained that fallen leaves would still remain on the earth’s surface for a long time unless drilodefensins existed and they would form a thick layer of leaves. This means that the entire system of carbon cycling won’t function properly.
A researcher involved in the study, Manuel Liebeke, explained that they were able to conduct the research using molecular microscopes which change the way in which the complex biochemistry of living beings is perceived. This technique enabled researchers to locate every molecule in earthworms. This allows researchers to understand what the molecules actually do.
Researcher Dave Spurgeon from the Center for Ecology and Hydrology explained:
We’ve established that earthworms, referred to as ‘nature’s ploughs’ by Charles Darwin, have a metabolic coping mechanism to deal with a range of leaf litter diets. In this role, drilodefensin support the role of earthworm as key ‘ecosystem engineers’ within the carbon cycle.”
The research team has also discovered that drilodefensins can be found in such large quantities that scientists estimated that each person on Earth could have at least two pounds. Researchers have also discovered that earthworms recycle drilodefensins and use it multiple times.
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