UK conker trees under threat from alien invading moths as scientists say Britain’s wasps are losing the insect war

Experts say there simply aren’t enough wasps to keep the horse chestnut-munching moths at bay

The UK’s conker trees are under threat because native insects are losing the war against an alien invader.

In less than three decades the horse chestnut leaf-mining moth, Cameraria ohridella, has spread from Greece to almost the whole of Europe, arriving on these shores around 10 years ago.

The moth, which burrows through the leaves of conker trees causing them to turn brown and die, was first spotted in south London in 2002 and can now be seen across almost the whole of England and Wales.

Experts had pinned their hopes on a species of tiny parasitic wasps, related to the larger black-and-yellow variety, which use the moth’s caterpillars to lay their eggs.

But a new reported published in the online journal Public Library of Science ONE revealed that the wasps are failing to keep up with the voracious appetites and seemingly unstoppable spread of their rivals.

In what has been hailed as a success for citizen science (if not for the conker trees), thousands of children across England and Wales were enlisted to record leaf damage and insect activity in their local area.

Volunteers were asked to find a visibly damaged – and therefore infested – horse chestnut leaf, seal it in a plastic bag for two weeks, and count the number and species of insects which emerged at the end.

A horse-chestnut leaf-mining moth which is winning an insect war in England and Wales A horse-chestnut leaf-mining moth which is winning an insect war in England and Wales Worryingly for the trees, the research revealed there were far fewer wasps than hoped, and not yet enough to slow the spread of the moths.

The study was designed to assess the impact of moths in a country where they had relatively recently arrived, and experts said there was still hope that wasp numbers might yet rally in response – as has been observed in other European countries.

Lead scientist Dr Michael Pocock, from the Centre of Ecology & Hydrology in Wallingford, Oxfordshire, 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.

“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.”

Co-author Dr Darren Evans, from 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.”

A total of 8,000 people took part in the Conker Tree Science project between 2010 and 2011.

Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksA special investigation by Andy McSmith
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Chiropractic Assistant

£16500 per annum: Recruitment Genius: A Chiropractic Assistant is needed in a ...

Recruitment Genius: Digital Account Executive - Midlands

£18000 - £26000 per annum: Recruitment Genius: They work with major vehicle ma...

Recruitment Genius: Web Developer

£28000 - £30000 per annum: Recruitment Genius: This company provides coaching ...

Ashdown Group: Front-End UI Application Developer

£30000 - £40000 per annum + Benefits: Ashdown Group: Front-End UI Application ...

Day In a Page

Where the spooks get their coffee fix: The busiest Starbucks in the US is also the most secretive

The secret CIA Starbucks

The coffee shop is deep inside the agency's forested Virginia compound
Revealed: How the Establishment closed ranks over fallout from Loch Ness Monster 'sighting'

How the Establishment closed ranks over fallout from Nessie 'sighting'

The Natural History Museum's chief scientist was dismissed for declaring he had found the monster
One million Britons using food banks, according to Trussell Trust

One million Britons using food banks

Huge surge in number of families dependent on emergency food aid
Excavation at Italian cafe to fix rising damp unearths 2,500 years of history in 3,000 amazing objects

2,500 years of history in 3,000 amazing objects

Excavation at Italian cafe to fix rising damp unearths trove
The Hubble Space Telescope's amazing journey, 25 years on

The Hubble Space Telescope's amazing journey 25 years on

The space telescope was seen as a costly flop on its first release
Did Conservative peer Lord Ashcroft quit the House of Lords to become a non-dom?

Did Lord Ashcroft quit the House of Lords to become a non-dom?

A document seen by The Independent shows that a week after he resigned from the Lords he sold 350,000 shares in an American company - netting him $11.2m
Apple's ethnic emojis are being used to make racist comments on social media

Ethnic emojis used in racist comments

They were intended to promote harmony, but have achieved the opposite
Sir Kenneth Branagh interview: 'My bones are in the theatre'

Sir Kenneth Branagh: 'My bones are in the theatre'

The actor-turned-director’s new company will stage five plays from October – including works by Shakespeare and John Osborne
The sloth is now the face (and furry body) of three big advertising campaigns

The sloth is the face of three ad campaigns

Priya Elan discovers why slow and sleepy wins the race for brands in need of a new image
How to run a restaurant: As two newbies discovered, there's more to it than good food

How to run a restaurant

As two newbies discovered, there's more to it than good food
Record Store Day: Remembering an era when buying and selling discs were labours of love

Record Store Day: The vinyl countdown

For Lois Pryce, working in a record shop was a dream job - until the bean counters ruined it
Usher, Mary J Blige and Will.i.am to give free concert as part of the Global Poverty Project

Mary J Blige and Will.i.am to give free concert

The concert in Washington is part of the Global Citizen project, which aims to encourage young people to donate to charity
10 best tote bags

Accessorise with a stylish shopper this spring: 10 best tote bags

We find carriers with room for all your essentials (and a bit more)
Paul Scholes column: I hear Manchester City are closing on Pep Guardiola for next summer – but I'd also love to see Jürgen Klopp managing in England

Paul Scholes column

I hear Manchester City are closing on Pep Guardiola for next summer – but I'd also love to see Jürgen Klopp managing in England
Jessica Ennis-Hill: 'I just want to give it my best shot'

Jessica Ennis-Hill: 'I just want to give it my best shot'

The heptathlete has gone from the toast of the nation to being a sleep-deprived mum - but she’s ready to compete again. She just doesn't know how well she'll do...