***Strictly embargoed until 2200 GMT London time / 1700 US Eastern Standard Time on Wednesday 22 January 2014***

Press release 2014/01 - Issued by the Centre for Ecology & Hydrology, UK


An army of citizen scientists has helped the professionals understand how a tiny ‘alien’ moth is attacking the UK’s conker (horse-chestnut) trees, and showed that naturally-occurring pest controlling wasps are not able to restrict the moth’s impact.

The study’s conclusions are published this week in the open access scientific journal PLOS ONE.

No bigger than a grain of rice, the horse-chestnut leaf-mining moth has spread rapidly through England and Wales since its arrival in London in 2002. The caterpillars of the moth ‘tunnel’ through the leaves of conker trees, causing them to turn brown and autumnal in appearance, even in the height of summer.

In 2010 thousands of ‘citizen scientists’ were asked by two professional ecologists to collect records of leaf damage from across the country as part of a project called ‘Conker Tree Science’.

The results show that over the last decade the moth has spread from London to reach almost all of England and Wales. Investigating the data further the scientific team concluded that it takes just three years from the first sighting of the moth in a particular location to maximum levels of damage to the horse-chestnut trees being recorded.

In a follow-up experiment, many of the citizen scientists, including hundreds of school children, followed instructions to rear the moth by sealing the infested leaves in plastic bags and waiting for the insects to emerge. The results reveal that the tiny pest controllers (‘parasitiod’ wasps) that prey upon the caterpillars are not present in high enough numbers to control the moths.

Dr Michael Pocock, an ecologist at the Centre for Ecology & Hydrology and lead author of the research paper said, “This is the sort of science that anyone can do. By taking part the public are doing real science – and the publication of this scientific paper is a demonstration of how seriously citizen science is now taken by the community of professional scientists.”

Co-author Dr Darren Evans, a conservation biologist at the University of Hull said, “This work could have been done by paying research assistants to travel the country and collect records, but by inviting thousands of people to get involved we, together, were able to pull this off much more cost-effectively.”

Dr Pocock added, “It seems almost like magic for children and other people to put a damaged leaf in a plastic bag, wait two weeks and then see insects – the adult moths or their pest controllers – emerge, but making these discoveries was a valuable contribution to understanding why some animals become so invasive.”

Dr Evans added, “We have been challenged by other professional scientists as to whether ‘ordinary people’ can make accurate observations, suitable for real science. Of course they can – and we tested this in our study. So thank you to the thousands of participants because together we were able to do this science.”

Unlike some other citizen science projects that use biological records submitted by members of the public for long-term monitoring, the Conker Tree Science project set out to test two specific hypotheses over the course of a year. The authors suggest that this approach can be developed to examine a range of environmental problems.

Conker Tree Science was run with funding from the Natural Environment Research Council and begun when the two authors were at the University of Bristol.

Notes for Editors

For more information please contact the CEH Press Office.

Paper reference: Michael J.O. Pocock and Darren M. Evans (2014) The success of the horse-chestnut leaf-miner, Cameraria ohridella, in the UK revealed with hypothesis-led citizen science. PLOS ONE. http://dx.plos.org/10.1371/journal.pone.0086226

Conker Tree Science is a project in which anyone can take part in real hypothesis led research. It was started in 2010 with two missions. The 8000 people involved in the project during 2010 and 2011 showed that both the amount of damage caused by the moth and the number of natural pest-controlling wasps increased with the number of years that the moth had been present in a location. In 2011 Conker Tree Science launched the LeafWatch smartphone app (for iPhones and Android) for people to record the damage to conker tree leaves.

The Center for Ecology and Hydrology (CEH) is the UK's Centre of Excellence for integrated research in the land and freshwater ecosystems and their interaction with the atmosphere. CEH is part of the Natural Environment Research Council, employs more than 450 people at four major sites in England, Scotland and Wales, hosts over 150 PhD students, and has an overall budget of about £35m. CEH tackles complex environmental challenges to deliver practicable solutions so that future generations can benefit from a rich and healthy environment. You can follow the latest developments in CEH research via CEHScienceNews on Twitter and our RSS news feed.

About the University of Hull - Inspired in Hull - The University of Hull has a long heritage of academic excellence. It was England’s 14th university when it was established in 1927 and received its Royal Charter in 1954. Its inspiring history includes major research in health, business, social sciences, the performing arts and science. Liquid crystal display (LCD) technology was developed in Hull and now underpins most mobile and computer screens. Still inspiring today - The University has more than 20,000 students across two picturesque campuses in Hull and Scarborough. A vibrant and ambitious institution, recognised for excellent teaching, student experience and graduate employability, as well as first-class research and enterprise. To find out more about how you could be inspired in Hull visit its website, view its Twitter feed, or see its Facebook page.

NERC is the UK's main agency for funding and managing world-class research, training and knowledge exchange in the environmental sciences. It coordinates some of the world's most exciting research projects, tackling major issues such as climate change, food security, environmental influences on human health, the genetic make-up of life on earth, and much more. NERC receives around £300m a year from the government's science budget, which it uses to fund research and training in universities and its own research centres.