Notorious Invasive Worm Found in U.S.

Notorious Invasive Worm Found in U.S.

The New Guinea flatworm, one of the most invasive animal species in the world, is on the move and has invaded 6 new locations, including Florida and the continental U.S., according to a new research. The “Platydemus manokwari” worm is on the ‘100 worst invasive animal species’ list, and is now newly located in Puerto Rico, Florida, New Caledonia, Singapore and the Solomon Islands, according to the study.

Physical Description

Platydemus manokwari (New Guinea Flatworm)


As its name suggests, the worm is indeed very flat. At rest the flatworm is broadest in the middle, tapering to each end. Adults are about 40 mm long and 4 – 5 mm wide. Some of them may attain a length of 70 mm. Their mouth is just behind the midpoint of the belly, and on a half-way between the mouth and hind end, is a genital pore. Two large prominent eyes are placed back from the tip of its elongated head.

The back of this animal is light to dark olive, and darkest on either side of the pale white stripe that runs along the mid-back and at the margins. The olive color grades to grey at the head end. On its body along each side are thin white stripe with fine greyish margins. The belly is white, with a white mid-ventral stripe. Newly emerged hatchlings are up to 9 mm long, with a pale brownish color extending dorsally and submarginally, a thin pale median dorsal stripe, white ventral surface.

Why Are They Dangerous?

Although the worm lives on the ground, it is able to climb trees to follow and consume prey. International team of scientists identified the dreaded worm at the various sites based on DNA sequencing, observations and other techniques because the worm feasts generally on native molluscs, threatening their populations. The presence of these flatworms in mainland U.S. in Florida should be considered a major threat to the U.S. and even the whole America.

Until now, infested areas were mostly islands, and the spread of these animals from island to island is limited. In expansive territories that are not islands, they are ready to spread throughout the whole territory.

The mollusks that they eat are local snails, which might sound like a good idea if you are trying to rid your garden of these slimy animals, but native snails are important to the ecosystems, because snails eat fungi and rotting vegetation.

Snails also serve as food source for all sorts of local wildlife, including some mammals, insects, lizards, salamanders, snakes and birds. Some fireflies, in particular, love to eat snails. Such animals would be deprived of their food if the invasive flatworm gets its way. Because the worm travels so far, it can easily be passively spread mainly with infested plants and soil. It’s important to remember that land snails are a key element and a major component of the entire animal diversity of North America, and of the ecosystems of this territory.

Eradication of the worms is challenging, because non-invasive species could be harmed in the process, so the scientists are now studying these flatworms, to better understand their biochemistry and life cycles.