Simply whenever you assume there can’t be the rest disastrous on the horizon, a brand new “plague” hits, leaving everybody scrambling to throw up hasty defenses.
Enter the Hammerhead Worm.
Hammerhead worms, a posh of species in a number of genera referred to as planarians, or terrestrial flatworms. Although native to tropical and subtropical Southeast Asia, hammerhead worms have develop into invasive worldwide, and have been reported in Arkansas for no less than a decade.
Jon Zawislak, extension apiarist for the College of Arkansas System Division of Agriculture, stated hammerhead worms are inclined to desire climates like these present in Arkansas.
“The worms are thought to have been by chance transported in soil by way of the worldwide horticultural commerce,” Zawislak stated. “These flatworms desire heat climates and really feel proper at dwelling within the southeastern United States.”
As a result of they require moist circumstances, the worms are unusual within the drier western deserts and mountain areas however can thrive in greenhouses wherever that preserve the correct circumstances, Zawislak added.
A number of species have been launched into North America since no less than 1901, however information on their distribution is spotty in lots of locations. One species, referred to as Bipalium kewense, or the Shovel‐Headed Backyard Worm, has been noticed in 10 completely different counties in Arkansas. A number of related‐wanting species have additionally been present in neighboring states, together with Bipalium adventitium, B. pennsylvanicum, Bipalium vagum and Diversibipalium multilineatum.
Studies of those invasive worms to nation brokers have develop into more and more extra frequent in the final yr.
“Gardeners have develop into conscious of those worms due to images and tales on social media and are actually extra alert and anxious about their presence right here,” Zawislak stated.
So the questions develop into: What do these non‐native worms do? And what ought to owners do about them?
Essentially the most visually distinctive attribute of those worms is their broad, spade‐formed head. Bipalium kewense has a protracted flattened physique that sometimes grows to eight to 12 inches, and typically even longer. They’re light-colored, with one to 5 darkish, skinny dorsal stripes. These worms are carnivorous and can prey on insect larvae, slugs, snails, and varied earthworm species.
Hammerhead worms are additionally identified to cannibalize one another. They will retailer meals reserves in
their our bodies and survive a number of weeks with out consuming.
Many species of hammerhead worms include a potent neurotoxin known as tetrodotoxin, which they use to immobilize their prey and defend towards predators. This is similar toxin present in pufferfish and some different animals. After they secrete this substance, it will possibly irritate your pores and skin if dealt with, and can sicken pets if eaten. As a precaution, gardeners ought to by no means deal with these
worms with out gloves.
Whereas usually present in hotter climates, hammerhead worms can survive chilly circumstances by in search of shelter. They have an inclination to keep away from the sunshine and are sometimes discovered resting in cool, damp areas in the course of the day, whereas they like to maneuver and feed at evening. They might be noticed beneath rocks, logs or thick vegetation.
Hammerhead worms are hermaphrodites and may mate with any member of their species, however extra typically reproduce asexually by fragmentation.
“Like many different planarians, if minimize into items, these creatures can regenerate every half right into a entire totally‐developed worm inside a few weeks,” Zawislak stated. “If injured, they’llrapidly regenerate broken tissue. These worms frequently break off items of their tails as they transfer alongside, leaving a bit behind to develop into a brand new worm. This capacity doubtless contributes to their success in colonizing new habitats.”
Hammerhead worms are thought-about extremely invasive, Zawislak stated, and a possible menace to native earthworm populations, in addition to gastropods resembling slugs and snails.
“Many earthworms have been launched to North America from Europe and different locations, and are useful to our gardens and lawns as a result of they aerate the soil, decompose and recycle vitamins, function meals for birds and different animals and are helpful fish bait,” Zawislak stated. “However these earthworms have been current right here for thus lengthy, they’ve built-in into our ecology, and will disrupt its steadiness if they’re eliminated now.”
Due to their cryptic habits, capacity to breed by fragmentation, and their lack of pure enemies in North America, hammerhead worms will doubtless show unattainable to regulate.
“They disperse slowly on their very own however are most likely unfold by folks extra quickly than we’re conscious,” Zawislak stated. “Worms could be transported with potted plant nursery inventory, in truckloads of topsoil or by development earthmoving tools. There’s no economically possible methodology to observe, management or eradicate these invasive worms.
“Hammerhead worms do have the potential to upset the ecosystem by preying on useful worms in addition to slugs and snails,” he stated. “However since they’re additionally cannibalistic, they could show to be their very own worst enemies.”
Zawislak stated that if a gardener spots a hammerhead worm, she or he shouldn’t hesitate to kill it.
“However you don’t wish to chop it in half together with your backyard trowel,” he stated. “Utilizing gloves, place it right into a plastic bag or different container with salt and vinegar, then freeze it in a single day earlier than disposing of it.”
Arkansans can report any suspected invasive species to the Arkansas Division of Agriculture’s Cooperative Agriculture Pest Survey workplace at
https://www.agriculture.arkansas.gov/plant-industries/regulatory-section/ag-pest-survey-program/.
Zawislak stated that whereas researchers are conscious that hammerhead worms are current in Arkansas, residents have as but to document many sightings. https://www.inaturalist.org/ is a citizen
science mission making an attempt to catalog all dwelling issues. Arkansans can add observations and be among the many first to assist monitor the unfold of this invasive worm.
