How Come Earthworms Can Digest Plants That Would Kill Most Other Animals?


Image Credit: Dr. Manuel Liebeke, Max Planck Institute

British scientist have finally cracked the mystery of the earthworm; how can the earthworm digest and breakdown plants full of defence poisons that would kill most other animals?. Earthworms are the decomposers of our global ecosystem, as carbon molecules are made in organisms above the ground, they are continually being broken down by organisms – such as earthworms- below the ground. However, some plants have evolved to produce poisonous molecules to discourage herbivores from eating them. These toxins stay viable even when the plant is dead and is being incorporated into the soil. So why don’t these toxins kill earthworms?

Manuel Liebeke and Jakob Bundy of Imperial College in London, along with their colleagues, have a report in the journal ‘Nature Communications’ explains that the earthworm’s gut contains a suit of molecules that neutralise the polyphenols that give plants their colour, serve as antioxidants and discourage many ravenous grazers. The internal defences have been identified and named drilodefencins, the scientists say that these molecules are extremely abundant (about 1kg for each person on the planet).

“Without drilodefensins, fallen leaves would remain on surface of the ground for a very long time, building up a thick layer. Our countryside would be unrecognisable and the whole system of carbon recycling would be disrupted,” Dr Bundy said.

Source: The Guardian


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