The Worm Turns

Our first adult earthworm of the year showed up Sunday afternoon, writhing along on the concrete patio just outside the office door. Clearly, that wasn't a good place for it to be — since the nearest earth was a crack full of ants between the nearby paving stones — so I moved it out into the garden where it could dig its way back into the soil. It appears this is a Lob Worm (Lumbricus terrestris), one of Britain's common grassland earthworms. Who knew there are 26 species of earthworm in Britain?! I sure didn't before I started trying to identify this one. The dark color on the first part of the worm, between the head and the "saddle" (that slightly wider, pinkish patch about 1/3 of the way down its body) combined with its length (7+ inches) and thickness (as thick as a pencil) help to identify it.

Earthworms are interesting creatures. They spend most of their life underground, typically coming to the surface only at night to mate or migrate. They're all hermaphrodites, with both male and female sex organs. They "breathe" through their skin, have a straight-through, tubular digestive tract, and "see" light through photosensitive cells on their backs. Most garden varieties live a year or two, though some species are known to live as long as eight years. They play a huge role in improving the soil, converting vast amounts of decomposing organic material into soil. Estimates of the number of earthworms in soil are truly staggering: recent research suggests that even poor soil may support 250,000 worms per acre, while rich farmland may support up to 1,750,000 per acre! Somehow, I don't think we have quite that many here.