Horsehair worms are thread-like water lovers that often appear in damp soil. Individuals sometimes spot them in the garden after a drenching rain or crawling on the surfaces of leaves and other vegetation. While their life cycle may sound a bit like a horror movie, they are actually beneficial.
Within the group Nematomorpha, these are also known as Gordian worms. They are very thin and adults are long, ranging up to 14 inches. Their common name originates from the belief that tail and mane hairs shed from a horse would come to life when they fell into a trough. In some regions, these worms are also referred to as “hair snakes,” “hair worms,” and “cabbagehair worms.”
While more common in ponds or other bodies of water, horsehair worms also thrive in moist soil and mud. One female can lay millions of eggs at one time, often in strings that attach to aquatic plants. Hatching takes place from two-twelve weeks and the young larvae seek out plants as shelter. At this stage, they become food for many types of insects, including grasshoppers, crickets, roaches, snails and other creatures. This is only the beginning, however.
Once consumed, they continue thriving inside their insect host. As a parasite, they feed on internal organs. They continue to grow in length, forming a tight ball and eventually escaping when the host takes a drink or is killed. In the former case, the insect will die when the mature horsehair worm exits. While thriving internally, the worm is albino colored, but once living outdoors, it develops darker shades of yellows and browns.
Horsehair worms can easily find their way into homes through this type of parasitization. When someone squashes a host insect, the worm will escape. They can appear in toilets, around sinks and any place the dead insect may be discarded.
Experts do not recommend pesticides to treat horsehair worms. They are harmless to everything but their larval host. They do not damage plants or infect animals and humans, and as adults, they do not eat. While they are indeed beneficial by finding such homes as roaches and crickets, these insects generally reach adulthood before meeting their demise. The worms can, however, become a nuisance at certain times of the year, which is often dependent on the existing insect population as well.
Horsehair worms commonly form writhing balls with their long twisting bodies, which is often equated to the legendary “Gordian Knot.”
All About Worms is always free, always reader-supported. Your tips via CashApp, Venmo, or Paypal are appreciated! Receipts will come from ISIPP Publishing.