Hammerhead worms in West Virginia

Melondy Phillips
Staff Writer
 
Hammerhead worms, Bipalium, are a  genus of large predatory land planarians and are an invasive species native to Southeast Asia. The hammerhead worm, like the hammerhead shark, received its nickname due to the shape of its head. They generally have a flattened body, earth colors, may have one or more strips, rings, spots or other markings, and may grow up to 20 inches long. The first flatworms traveled to America in the roots of plants distributed from greenhouses for landscaping. The first reported sighting of a hammerhead worm was in Texas, and there have been reported sightings of them across America since 1980. Land planarians, or flat worms, are restricted to very specific environments due to their lack of water-retaining capability. This makes them very sensitive to their environment so they have a tendency to reside in tropical and subtropical areas or other humid locations. Crossing arid regions and becoming established in new locations may be as simple as hitching a ride in the soil of someone’s plants. 
 
What do hammerhead worms do?

Flat worms do not like being touched and will produce a slimy film when handled.

The compound tetrodo-toxin, which is found in Fugu pufferfish, is also present in the hammerhead worm.  James Murphy, an agriculture agent with UGA Extension in Rockdale, Georgia, said that you would likely need to ingest the worm for any poison to enter your body and possibly a lot of them to be severely poisoned. With this being said, some people may be more sensitive to skin contact than others and might develop a rash, so gloves are recommended when handling them. Illness may develop in some animals if they eat these worms in large quantities; however, most animals find them distasteful and will ignore them.

Hammerhead worms use the slimy and sticky mucus they produce to first paralyze the victims they wrap around. They then use special enzymes, released in the mucus, to digest their prey while it is outside of their body. After the digestive juices have liquefied their prey, they consume it by using tiny hairs, called cilia, to move the dissolved mass into the mouth on their belly. They use these same microscopic hairs to travel as they guide themselves over a trail of mucus they secrete from their underside. The head and part of the neck are held in the air and move side to side as they “crawl.”
 
What do hammerhead worms eat?

Hammerhead worms are carnivorous in nature and can even be cannibalistic. Being sensitive to light, they mainly feed during the night on such things as snails, earthworm, slugs, some small insects, and other soft bodied invertebrates. One of their primary food sources is the earthworm. Hammerhead worms do not aerate and fertilize the soil like earthworms do. If the population of hammerhead worms grows too large in an area and they consume too many native earthworms, the soil fertility can dwindle, causing crop shortages due to poor soil conditions. This is not only a concern for farmers but should also be disconcerting for anyone who eats produce. Besides the devastation they create by eating the beneficial soil fauna they also transmit harmful nematode parasites in their wake; having the ability to affect people, plants, and animals.
 
How do hammerhead worms reproduce?

Hammerhead worms are hermaphrodites, containing both the male and female reproductive organs, and are also able to replicate through fission. Fission is similar in concept to mitosis, but instead of only making more cells for the body, fission is a way to clone or replicate another whole organism. Because of the ability to do this, they will multiply in numbers when cut in half. 
 
A possible up side to flatworms

Erin Davies, of the National Institutes of Health’s Cancer and Developmental Biology Laboratory, began research on the adult pluripotent stem cells (PSCs) in the flatworms for the possibility of “tumor suppression or other facets.” 

“Planarians are a remarkable model system,” said NCI-CCR Scientific Director Tom Misteli. “Its arrival in the intramural program offers a powerful new tool to study regeneration, differentiation, and stem-cell biology, all processes that are highly relevant to many diseases including cancer.” The full article can be found at https://irp.nih.gov/catalyst/28/5/using-flatworm-regeneration-to-study-stem-cells 

Personal experience 

I have read many statements, by people throughout West Virginia, saying they are glad that these worms are not here; sadly, I can testify that this is not the case. Although this region is not as friendly to the hammerhead worms as other parts of the county, it is still important to vigilantly be on the lookout for, and to capture and report these invaders. 
 
What to do if you find a hammerhead worm?
 
When you find a hammerhead worm, first take a picture of it. Do not cut up the worm; instead, use gloves or another item to pick up the worm and place it into a baggie or jar.  Contact your local extension office to report the finding; this will help them track the location of this invasive species. Ask if they want it for testing or if you should dispatch it. If they say to dispatch it then cover the worm with salt, vinegar or alcohol.  

One way to rid hammerhead worms from the soil is to use boric acid about every two weeks.  This creates an acidic environment, which they cannot live in. Be advised that using boric acid and making the soil acidic can affect the ability to grow certain crops in that soil; it is also harmful to many beneficial insects and worms. 
 
The take-away

1. Being vigilant, along with due diligence, is advised when stumbling upon one of these unusual looking creatures since there are some reasons for concern. 

2. Parts of the world have habitats in which the hammerhead worm will proliferate; however, most of the United States’ environment will keep them at a slow crawl.

3. These little pests have been around for a long time and are not going to come after you while you sleep or poison you if you accidentally step on one.