Invasive worms emerging after Texas rains. Whatever you do, don’t cut them in half

Rainfall across Texas has likely forced an invasive worms species — which can be nearly a foot long — to emerge from the ground, experts say.

The Texas Invasive Species Institute says reports of hammerhead flatworms have skyrocketed after a viral Facebook post about a sighting in the Dallas-Fort Worth area.

The post about the slimy creature appearing in a backyard had nearly 60,000 shares by Friday.

Ashley Morgan-Olvera, the institute’s director of research and outreach, confirmed to McClatchy News that the worm sighting was authentic.

She said the institute has received more than 200 reports of hammerhead flatworms in the past few days. Though the species is more established in Southeast Texas, most recent reports have been from Tarrant, Dallas, Smith and surrounding counties, Morgan-Olvera said.

“So unfortunately it seems they’re widespread there as well,” she told McClatchy in an email.

A predator of earthworms, a hammerhead flatworm can grow up to 30 centimeters, or just shy of a foot, according to the Texas Invasive Species Institute. They’re marked by a half-moon shaped head similar to sharks of the same name. They’re sometimes called hammerhead slugs.

Because they prey on earthworms, which are vital to a healthy habitat, hammerhead flatworms are considered an invasive species. To digest earthworms, they secrete a neurotoxin that can irritate skin or sicken pets for a few days if eaten, Morgan-Olvera said.

“The final threat is that like other flatworms, slugs and snails they have the ability to transmit harmful parasites to humans and mammals alike,” Morgan-Olvera said. “All of these reasons are why we do not want you to handle them with bare hands and encourage you to properly dispose of them from your property.”

So, what should you do if you find one?

Definitely don’t cut it in half. Hammerhead flatworms are hermaphroditic, but “sexual reproduction has not been observed,” according to the Texas Invasive Species Institute. The species seems to primarily reproduce through fragmentation, when a small rear part of the worm breaks off and begins to form its own head within 10 days.

“So when we cut them into pieces we’re just helping them along,” Morgan-Olvera said.

Hammerhead flatworms should be handled with gloves, and hands should be washed with hot, soapy water and rinsed in alcohol or hand disinfectants afterward.

Morgan-Olvera told WFAA that people who find the worms should put them in sealed bags with salt or vinegar and freeze them overnight.

Anyone who finds a hammerhead flatworm is encouraged to report it to the Texas Invasive Species Institute.

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