​​​​​​​Insects are victims too: Global study shows impacts of invasive alien species on populations

Insects are often seen as invaders due to high-profile species like the yellow-legged (Asian) hornet, the harlequin ladybird and fire ant. but new research reveals insects are also major victims of invasive alien species – exacerbating population declines and reducing their ability to provide vital services for biodiversity and people from pollination to pest control.

The first global analysis of its kind, led by the UK Centre for Ecology & Hydrology (UKCEH), revealed that invasive alien species reduce abundance of terrestrial insects* by 31% on average and reduce species richness by 21%. Invasive animals outcompete or eat insects while invasive vegetation replaces native plants that insects feed upon.

The study, which analysed data from six continents, shows certain terrestrial insect groups including bees, wasps, ants and true bugs are more negatively affected by invasive alien species than others, such as beetles. But the authors point out that the outcomes vary, depending on the dynamics of the local environment – for example, invasive plants might support insects in places where native vegetation has been lost.

Invasive alien species are already recognised by IPBES as one of the five big direct drivers of global biodiversity loss, alongside land- and sea-use change, direct exploitation, climate change and pollution. These threaten nature, economies, food security and human health.

Grace Skinner, a data scientist at UKCEH who led the new study, said: “It is crucial that we recognise insects not just as invaders but also as victims of invasion. Insects are undergoing concerning declines across the world and as this trend continues, essential ecosystem services will increasingly be at risk.

“Identifying the insects most vulnerable to biological invasions will support better prioritisation of habitat management and also action to prevent and control invasive alien species. This is particularly important when resources are limited.”

It is widely acknowledged that insects are struggling globally, though the magnitude of change varies among species and regions. Despite invasive alien species being a major global threat, their effects on insects have been far less studied than other pressures such as urbanisation and nutrient enrichment. This is the first study to analyse and quantify the impact of invasive alien species on insects on a global scale.

Global transport results in the increased spread of non-native species to new regions while warmer temperatures create more suitable conditions for populations to thrive in some of those areas. 

Scientists warn the multiple challenges to insects will increase further. “We hope our analysis encourages more research into how invasive alien species interact with other threats to insect biodiversity – for example how climate change might influence invasive alien species populations and amplify their impacts,” said study co-author Dr Joseph Millard of the University of Cambridge.

The study, funded by the Natural Environment Research Council, has been published in the journal Nature Communications. It focused on four animal orders, representing 62% of all insect species, that experts have identified as being particularly threatened by invasive non-native species.

The analysis found the average reductions in abundance were: Hemiptera (true bugs) – 58%; Hymenoptera (ants, bees, sawflies and wasps) – 37%; Orthoptera (grasshoppers, locusts and crickets) – 27%; and Coleoptera (beetles) – 12%.

Scientists point out that tackling invasive alien species is urgent but achievable. Enhancing cross-border collaborations on biosecurity is critical to preventing the spread of species to new regions and individuals can make a difference. Gardeners are advised to carefully consider their choice of plants, while anglers, boaters and forestry workers, for example, should ‘check, clean, dry’ equipment.

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Media enquiries

An embargoed copy of the paper, an infographic and some suggested images are available on request. For an interview with a scientist or further information, please contact Simon Williams, Media Relations Officer at UKCEH, via simwil@ceh.ac.uk or +44 (0) 7920 295384

Paper information

Skinner et al. 2025. Meta-analysis reveals negative but highly variable impacts of invasive alien species on terrestrial insects. Nature Communications. DOI: 10.1038/s41467-025-67925-9. Open access.

The analysis, which was based on 52 studies from across the world, involved researchers from UKCEH, the University of Cambridge, University of Exeter, University College London, the Zoological Society of London and Stellenbosch University. It received funding from the Natural Environment Research Council (NERC) as part of the GLiTRS (Global Insect Threat-Response Synthesis) project.

About the UK Centre for Ecology & Hydrology (UKCEH)  

The UK Centre for Ecology & Hydrology (UKCEH) is a leading independent research institute dedicated to understanding and transforming how we interact with the natural world.  

With over 600 researchers, we tackle the urgent environmental challenges of our time, such as climate change and biodiversity loss. Our evidence-based insights empower governments, businesses, and communities to make informed decisions, shaping a future where both nature and people thrive.  

www.ceh.ac.uk / ukceh.bsky.social  / LinkedIn: UK Centre for Ecology & Hydrology