Fig. 4.

Global maximum impact severity for invasive alien insects is a function of alien geographic range. A. Alien geographic range variation (number of countries with alien populations) for species within each maximum impact severity classification. Most species had a maximum impact of Minor or Moderate severity. Impact severity categories are Minimal Concern (MC, impacts on native taxa negligible), Minor (MN, decreased performance of native taxa but no evidence of population decline), Moderate (MO, native species population declines but no evidence of local apparent extinction), Major (MR, reversible local extinction of native taxa) (there were no species assessed as having a Massive (MV) impact, irreversible local extinction of one or more native taxa) (for full descriptions of categories used see (Clarke et al., 2021). B. The relationship between geographic range and environmental impact severity of alien insects. The probability that the global maximum realized impact of an alien insect species falls in the most severe category (Major) is higher for those species established in the most countries, and lower for those species established in fewer countries.