In 1990s, Samoa released a predatory flatworm as a weapon against giant African land snails. 49 years later, the predator has outlived its original target-control mission and threatens native snails instead

A predator introduced to solve one invasive-species problem ended up creating another. In Samoa, the New Guinea flatworm was brought in during the 1990s as a biological control agent against giant African snails that were damaging crops. But the flatworm did not stay focused on its intended target. It also hunted native land snails, including tree-dwelling species that had evolved without this particular predator, as per a report by El Cronista.

The result became a warning about how quickly biological control can upset an island ecosystem.