The artist of the soil, the Earthworm!

I had wondered in my childhood about the straight lines found on the muddy soil: it was raining the previous evening; who would have drawn them overnight! As I grew up, I understood who it is: the lines were drawn by worms, the Earthworms! (term and names: Lumbricus terrestris, Rain worm, Night-crawler, Angleworm, 'Munpulu' in Tamil). Though these brownish worms are found in rainy season, their presence in summer can also be inferred by the mud-disrupted lines on the irrigated farm grounds.

On close look, the segments of this worm can be seen as rings all along its length. Clitellum, the thickening on the anterior segments, aids it in forming cocoon for its eggs. The segments from 9th to the 15th one bear sexual organs. The worm moves by contracting its longitudinal and circular muscles, assisted by the bristle-like setae that are found in all the segments. The organic matter that it swallows with the soil, is ground and digested; ejected out as casts after nutrients are absorbed. The worm respires through its slimy skin.

It is a hermaphrodite; but a pair of worms mate to transfer sperms and fertilize eggs mutually. The eggs are enclosed at the clitellum in cocoon that is loosened, passed and released away like a ring! This worm is preyed upon by birds, beetles, snails and snakes. It has a lifespan of about two years. It is also used as a bait in angling for fish, as it is a delicacy for fish. If it is cut, it can generate its lost part! It is a well known 'friend of farmers' as it aerates  farm soil, and also fertilizes it with its worm-casts.

Such a wonder worm that intrigued me is a useful animal for the entire human society!