new guinea flatworm
Invasive New Guinea flatworm
One of the world's most invasive species, the New Guinea flatworm, is on the move and has just invaded six new locations, including the continental U.S. — Florida — according to a new study.

The worm (Platydemus manokwari) is on the "100 worst invasive alien species" list, and is now newly located in New Caledonia, Singapore, the Solomon Islands, Puerto Rico and Florida, according to the study, which is published in PeerJ.

Although the snail lives on the ground, it is able to climb trees to follow and consume prey.

Jean-Lou Justine of the Sorbonne's National Museum of Natural History and his international team of colleagues identified the dreaded worm at the various sites based on observations, DNA sequencing and other techniques.

Because the worm feasts heavily on native mollusks, threatening their populations, the researchers write that "the newly reported presence of the species in mainland U.S. in Florida should be considered a potential major threat to the whole U.S. and even the Americas."

Until now, infested territories were mostly islands, and the spread of the species from island to island is limited. In expansive areas that are not islands, the world is this flatworm's proverbial oyster, ready for takeover.

As its name suggests, the worm is indeed very flat. Its back is a black olive color with a clear central stripe, and it has a pale white belly. Its head is elongated with two prominent black eyes. Its mouth is actually in the middle of its belly.

The molluscs that it eats are local snails, which might sound like a good idea if you're trying to rid your garden of these slimy creatures, but native snails are critical to their ecosystems. They eat very low on the food chain, often consuming rotting vegetation and fungi.

Snails also serve as food for all sorts of local wildlife, including certain insects, lizards, snakes, salamanders, birds and mammals. Some fireflies, in particular, love to munch on snails.

Such animals would be deprived of their food source if the invasive flatworm gets its way. As for how the worm travels so far and wide, in addition to its own journeys, it "can easily be passively spread mainly with infested plants, plant parts and soil," Justine and his team write.

Eradication of the worms is challenging, given that other non-invasive species could be harmed in the process, so the scientists continue to study the worms, to better understand their biochemistry and life cycles.