Let's talk about Earthworms
If you’ve ever wondered about where the worms in our city parks — or in your own backyard — go in the colder seasons, you’re not alone. As you walk through one of our parks on a warm, sunny fall day you’ll see plenty of damp leaves and wet soil. If you gently turn over some of those leaves, it’s likely you’ll eventually see an earthworm. But where do they go as the weather gets chillier?
Typically when we talk about worms in Pittsburgh we’re referring to a class of worms called Oligochaete (ALL-ah-goh-keet). More commonly known as earthworms, they belong to a group — or phylum — called Annelida (AHN-ah-LEED-ah). This group also contains the leeches and ragworms that hang out at the creepier end of the worm spectrum.
While earthworms are sometimes thought of as simply being food for birds and fish, they also play an important role in the health of our soil. Worms are decomposers, breaking down small organic particles into dirt, which adds nutrients to the soil. The slime you may feel when carefully handling a worm is also a vital part of our soil’s health. It is high in nitrogen, which is left behind as worms dig paths through the ground. This burrowing serves a purpose, too, as it aerates and loosens soil.
There are 180 species of earthworms found in the United States, with about 60 of those species having been introduced from other countries. While earthworms live in nearly every place on Earth, there are no native worms in places where there were glaciers. Earthworms cannot survive prolonged severe cold, but even our coldest Pittsburgh winter can be outlasted by the earthworms. Some types of earthworms burrow deep — up to 6 feet — to find soil that is warmer, while others lay eggs that are capable of surviving the cold temperatures and hatch in the spring.
The earthworm’s survival mechanisms aren’t the only fascinating thing about them, as their bodies are also amazing. Earthworms have their hearts — five of them — and brains in the front end of their body, while the other end just has a simple digestive tract. In between the heart and digestive tract, there are hermaphroditic (both male and female) reproductive organs.
The next time you see an earthworm stretching its way across a leaf or tree bark in one of our city parks, take a moment to closely observe it. The magic of nature can be found in even the most common animals, and the earthworm is no exception.
Control Lawn Worm Soil Casts with CastClear
The “Let’s Talk About Parks” series is designed to encourage exploration and discovery of Pittsburgh’s urban parks.
Comments