A decade of recording harlequin ladybirds in the UK

Dr Helen Roy of CEH is among the scientists behind the UK Ladybird Survey which, thanks to the help of the public, has monitored the rapid spread of the non-native harlequin ladybird in the UK from its first confirmed appearance in 2004. Coinciding with a new paper in Ecological Entomology, Helen looks back at ten years of harlequin ladybird recording.

"The harlequin ladybird (Harmonia axyridis), heralded as “the most invasive ladybird on Earth”, was first recorded in the UK in October 2004. Within a few months the online Harlequin Ladybird Survey was launched as part of the wider UK Ladybird Survey. Over the last decade, tens of thousands of people have contributed their sightings of this invasive non-native ladybird (and other species of ladybird) to the UK Ladybird Survey.

"The result - a unique dataset tracking the invasion of a non-native species from the moment of arrival.

Harlequin ladybird (Photo: Ken Dolbear)

Today (20 May 2015) we celebrate the contributions of these inspiring volunteer recorders through the publication of a paper describing advances in understanding of the ecology of the harlequin ladybird in the UK. The paper builds on a paper published in the same journal in 2006 which made predictions about the impact of the harlequin.

There have been many exciting discoveries over the years and some rather bleak messages too. Much of the research on this species would have been impossible without the volunteer recorders. We have learnt so many lessons from these ladybirds.

Highlights include:

• The UK Ladybird Survey dataset highlighted that seven out of eight native species of ladybird were declining and this was strongly linked to the arrival of the harlequin ladybird.
• We have also explored the way in which the colour patterns of harlequin ladybirds, their association with different habitats and plants within these habitats, their reproductive behaviour, their flight patterns and so much more has influenced the spread of this species.
• The harlequin ladybird has been shown to be more resistant to parasites than other ladybirds.
• We have shared the dataset with other scientists across the UK and around the world and enjoyed comparing our findings with others who are studying the harlequin ladybird across Europe, South Africa, North and South America and Asia.
• The role of citizen scientists in this research has been inspiring and we have enjoyed sharing experiences with other citizen scientists and their projects to develop a citizen science.
• The number of new arrivals is increasing year on year and the number of records of H. axyridis received by the UK Ladybird Survey demonstrates the critical role that people can play in non-native species surveillance.
• The commitment of people to recording harlequin ladybirds encouraged the development of a recording system for other non-native species which is being used as an early warning tool for the Asian hornet and other species that are on the horizon. The demand for scientific evidence to underpin our understanding of the impacts of invasive non-native species on other wildlife continues to be high.

The next ten years

So what about the next ten years? We still have so much to learn about the harlequin ladybird and its interactions with other species. To date much of the research has looked at predation and we need to examine the importance of competition between harlequin ladybirds and other species, and our understanding of the resilience of the networks of species with which the harlequin ladybird intermingles. We are also asking people to tell us about the natural enemies (mainly parasites) of ladybirds as they observe them interacting with harlequin ladybirds and other species. It is possible that some of these incredible parasites will adapt to using the harlequin ladybird as a host – evolution in action!

Collaboration and working in partnership is so important and we have been delighted to have so many opportunities to work with so many people and organizations over the last ten years. We want to thank everyone who has contributed – it has been a privilege to work with you all. We hope that people will continue to be part of the UK Ladybird Survey. The smartphone app, iRecord Ladybirds, ensures that it is extremely easy to record sightings of all ladybirds. An incredible 12000 records have already been contributed through the app.

"So, if you see a ladybird, please record your sighting. Every record counts!"


Dr Helen Roy

Ten years of invasion: Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) in Britain. 2015. Helen E Roy and Peter M J Brown. Ecological Entomology.

CEH News:  Ten years of invasion -  a decade of recording harlequin ladybirds

UK Ladybird Survey: Recording ladybirds