The vital role that the public can play in helping to track invasive non-native species has been highlighted through a publication documenting the spread of the harlequin ladybird in the UK.

Thanks to the enthusiasm and commitment of citizen scientists, 48,510 verified reports of the ‘alien’ species in the UK have been contributed over 13 years, according to academics from Anglia Ruskin University and the Centre for Ecology & Hydrology.

A summary of the data including an overview of the methods has now been published in the Nature journal Scientific Data. The records, from 2003-2016 – which are available to view for free online – show how the harlequin ladybird, which is a species native to Asia, has spread across the UK.

After being introduced to mainland Europe in the 1980s to control aphids, there is evidence that the harlequin arrived in the UK in 2003, with the first public reports of sightings the following year. The harlequin is now attributed as a factor behind the declines of other ladybird species.

Spreading at over 100km per year during the early stage of invasion, the observations show harlequins are now widespread throughout England and Wales and increasingly reported in the south of Scotland.

See our video below showing the spread of the harlequin across the UK

The authors of the new study say the rapid flow of information about the occurrence of invasive non-native species is critical to inform effective action to deal with them, and the citizen science approach developed through the UK Ladybird Survey is already being used for surveillance of other invasive non-native species, including the Asian hornet.

Professor Helen Roy, from the Centre for Ecology & Hydrology, a co-lead of the study and an expert on invasive species, said: “It has been incredible to see the way in which so many people have got involved in tracking this invasion – it is a truly collaborative project.

“We have been able to answer many important ecological questions using this vast dataset. This would not have been possible without these inspiring citizen science contributions.”

In Britain, a Coccinellidae Recording Scheme has been run through the Biological Records Centre at the Centre for Ecology & Hydrology since the early 1970s and the online UK Ladybird Survey was launched in 2005.

All records included in the harlequin ladybird dataset were either from known experts or were verified by a recognised expert based on photographs or in some cases specimens.

The research for the new study was funded by the Natural Environment Research Council, the Joint Nature Conservation Committee and Defra.


PMJ Brown, DB Roy, C Harrower, HJ Dean, SL Rorke, HE Roy. Spread of a model invasive alien species, the harlequin ladybird Harmonia axyridis in Britain and Ireland, Scientific Data (2018). DOI: 10.1038/sdata.2018.239
The full dataset is available here.

CEH's citizen science apps webpage

CEH news relating to the dataset:
- Invasive alien predator causes rapid declines in European ladybirds
City life key to harlequin ladybird invasion 
- Blog   


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Community ecology, invasion biology, entomology, biological recording, science communication

Career summary:

2019 -               Ecologist (Individual Merit (IMP) Scientist and Group Leader, NERC Centre for Ecology & Hydrology)