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Crucial for the functioning of ecosystems, they face numerous threats; Invasive alien species are the most serious.
Os insects are often seen as “invaders”, associated with popular species such as the Asian wasp, the harlequin ladybug or the fire ant.
But a new alert for the other side of the story: in much of the world, insects are also among the main victims of invasive alien species — with direct impacts on biodiversity and essential services for people, such as pollination and natural pest control.
The first global analysis of its kind, led by the UK Center for Ecology & Hydrology (UKCEH), finds that invasive species reduce, on average, the abundance of terrestrial insects by 31% and species richness in 21%.
According to the authors, the mechanisms they are several: Invasive animals may compete with insects for resources or prey on them, while invasive plants replace native vegetation that serves as food and habitat.
The decline is not uniform between groups. The study estimates average abundance reductions of 58% in Hemiptera (the “true bugs”), 37% in Hymenoptera (which include ants, bees and wasps), 27% us Orthoptera (grasshoppers and crickets) and 12% in Coleoptera (beetles).
The study analyzed data from six continents; indicates that Bees, wasps and ants tend to be more affected than beetlesalthough the effects vary with local dynamics: in areas where native vegetation has already been lost, certain invasive plants can, in some cases, sustain insect populations.
Invasive alien species are one of the five major direct drivers of global biodiversity loss, alongside changes in land and sea use, direct exploitation, climate change and pollution.
For Grace Skinner, from UKCEH, recognizing insects as “victims of the invasion” is crucial to guide habitat management and prioritize actions when resources are limited, cites .
The researchers emphasize that the spread of non-native species is driven by global transport and higher temperatures. They advocate strengthening biosecurity and cross-border collaboration, in addition to practical measures: choosing plants carefully and applying the “check, clean, dry” principle to equipment used by fishermen, vessels and forestry sectors.
