People around the UK are being asked to help researchers from the University of Aberdeen and the James Hutton Institute pinpoint just how far an invasive species has spread throughout the UK.

The New Zealand Flatworm landed on British Soil over half a century ago but researchers have struggled to track the species movements as they are typically found in gardens. It eats an exclusive diet of earthworms, and it is not yet known what influence this has on earthworm numbers or indeed on the populations of animals like moles which also consume earthworms.

The Open Air Laboratories (OPAL) have launched a new survey this month, to help find out how far the New Zealand Flatworm has spread and how big an influence it is having on the environment. This is the latest addition to the range of citizen science surveys offered by OPAL which is led by Imperial College London and run by a wide range of organisations including the Glasgow Science Centre.

The harmful potential of the New Zealand Flatworm makes it a creature of interest to OPAL and indeed many gardeners. It consumes earthworms by wrapping its body around the worm and secreting digestive mucus to dissolve and consume it. They have the ability to survive for over a year without eating and if food becomes scarce they can shrink to about 10% of their full grown body mass surviving like this until another earthworm comes along. This means that earthworm populations that are decimated have little chance to recover so long as New Zealand Flatworms remain in the area. However it also means that they don’t spread far on their own and their spread is due to human activities.

Members of the public who are keen to be involved in this new citizen science survey are advised that the species is between 5-15cm long and flat with a dark purple/brown topside and a creamy pale underside and edge, they are pointed at both ends and covered in sticky mucus which they leave a trail of wherever they have been. They are regularly found under wood, stone or polythene or on bare earth, often curled up like a Swiss roll.

New Zealand Flatworms are spread by moving topsoil or rooted plants between places, which allow the species to move, in the soil, from garden to garden. Current understanding of their whereabouts is very limited, but knowing their distribution could help target initiatives to prevent further introductions.

This is where you come in! OPAL is collecting information on the distribution of the New Zealand Flatworm for the researchers at Aberdeen University and the James Hutton Institute where leading research into the New Zealand Flatworm is being carried out. If you find one, in your garden, or elsewhere, please take a photo and submit it along with its location to This will give the team an idea of what influence there flatworms may have on the UK ecosystem, especially our earthworm populations. Even negative results are invaluable, knowing where the New Zealand Flatworm is absent is just as important in managing their spread as knowing where the already are.

Dr Brian Boag, one of the experts based at the James Hutton Institute said: “Avid gardeners will know whether they have New Zealand Flatworms on their premise or not, but this understanding is not passed on. Therefore, we would love to learn from people to get a clear picture of where these creatures are present and where not.”

Professor René van der Wal, from the University of Aberdeen, who is one of the leaders of this new initiative, said: “We want to get people looking carefully at their gardens and the greenspaces around the cities and towns they live, and school kids to explore their play grounds, in search of this rather peculiar species, and tell us what they’ve found. Ideally, they spend 10 minutes searching for flatworms, earthworms, beetles and signs of moles in a relatively structured way and tell us about their findings”.

Joanne Dempster, an OPAL Community Scientist based at the Glasgow Science Centre added: “By taking part in this survey gardeners could make a real difference for our incredibly valuable earthworm population. Every result, whether you find them or not, will help researchers evaluate the impact they are having and develop an appropriate response. People can access information on identification and how to take part on the OPAL website, helping us to learn more about the New Zealand Flatworm and its effects on the local ecosystem.”



OPAL Explore Nature: New Zealand Flatworm survey

Glasgow Science Centre

For further information, please contact Glasgow City of Science’s OPAL community scientist based at Glasgow Science Centre, Joanne Dempster on 0141 420 5010 (ext 270) or email.