January Bug of The Month: Flatworms

Platyhelminths are the creatures that we call flatworms, and they can be recognised by their flat ribbon-like, slimy bodies which have no appendages or tentacles. In addition, platyhelminths have no body cavities and will acquire oxygen and nutrients by absorption through their skin.

Assumed to be the oldest living ancestors of all bilateral animals, fossil evidence suggests that platyhelminths have remained unchanged in appearance for over 500 million years and encompass species that live within aquatic environments as well as those that are endoparasites such as tapeworms.

Britain’s first invasive soil dwelling platyhelminth though, was recorded in the 1960’s, and was identified as the New Zealand flatworm, a dark brown coloured creature that, when fully grown could reach 8 inches in length. As increasingly more New Zealand flatworms were discovered in home gardens, concerns grew for the detrimental effects in might be having on Britain’s ecology since it was a rapidly reproducing species that was a significant predator of earthworms.

Smaller than the New Zealand flatworm though, the Australian flatworm was orange in colour and seems to have spread and become established throughout the southern counties of Britain. Despite the discovery of other invasive platyhelminths over recent years, the New Zealand and Australian species are assumed to be the only flatworms to have become properly established in Britain and are continuing to be found within home gardens where they can remain active throughout the year.

Controlling infestations of a soil-dwelling Platyhelminth though is not easy since there are no chemical products available. Flatworms are also capable of reproducing by a process called fission which entails detached sections of their body growing into new individuals.

If platyhelminths are found within a garden though, it’s advisable to take a photo or collect a specimen, and then report it to the British Non-Native Secretariat.