Earthworms and Nutrition

Earthworms are one of the most versatile invertebrates. They can eat almost anything and benefit the environment in doing so. What exactly they eat is dependent on whether they live above the soil or deep in the ground. They will also feed on pretty much anything in a compost pile.

Earthworms have no teeth. Instead they moisten bits of food in their mouth to begin breaking it down. Then the food is passed to the gizzard, which acts like teeth to grind down the food further. Last, the intestines break down the remaining food and pass out the excess as worm castings.

Earthworms that reside on the surface of the soil will eat any organic material surrounding it. This most commonly will include dead grass and leaves. This organic material is covered in algae, fungi and bacteria that are essential to the earthworm's diet. In a compost heap, the worm will digest anything from cardboard to melon rinds.

Earthworms that reside underground do not have the organic material that is available above ground. Instead these invertebrates will eat and digest raw dirt. This dirt contains the bacteria, fungi and algae that the earthworm can acquire above ground. Sometimes they swallow small stones to aid in digestion and grinding their food.

Earthworms have developed a high capacity for oxygen storage. Underground the soil is oxygen-poor, yet the earthworm is able to inhabit these conditions. They are the most populous in grasslands, where organic material is abundant and disturbances are few. The earthworm's diet extends so far as to include dead and decomposing earthworms.

The earthworm's acquisition of nutrients plays a vital role in maintaining ecological balance. In their hunt for organic matter, earthworms burrow through the soil. This burrowing aerates the soil and provides space for rain water to be absorbed. Earthworm feces, known as castings, provide fertilization for plants and crops.