The world’s 100 worst invasive alien insect species

Abstract

While there has been great interest in species characteristics that promote invasiveness, still little is known about the characteristics that distinguish invasive from non-invasive insects. Using a database on the naturalized distributions of alien insects and expert opinions about their impacts, we identified the world’s 100 worst invasive insect species. By comparing species characteristics reported in the literature using a meta-analysis, between the 100 worst invasive species and related non-invasive species, we found that invasive insects overall have more pathways of introduction, occur in more habitats, have higher fecundities, higher voltinism, more genes, shorted lifespans and faster development from egg to adult. Some of the differences in species characteristics are related to propagule pressures, life-histories and biotic interactions, conditional on whether the non-invasive species compared is known to be naturalized somewhere, whether the invasive species is globally distributed, and the climatic region of the species. Synthesis and applications: We show for the first time, using a multi-species comparative approach, that invasive insects differ in several characteristics from related non-invasive insects. Our results show that invasive species, such as Spodoptera frugiperda, typically are habitat generalists with a high fecundity, a short lifespan, and fast development, whereas the importance of female body size and number of enemies are context dependent. Our study can guide and improve existing screening tools for assessing the invasion potential of alien insects.