Moths and butterflies on alien shores: Global biogeography of non‐native Lepidoptera

Abstract

Aim Lepidoptera is a highly diverse, predominantly herbivorous insect order, with species transported to outside their native range largely facilitated by the global trade of plants and plant‐based goods. Analogous to island disharmony, we examine invasion disharmony, where species filtering during invasions increases systematic compositional differences between native and non‐native species assemblages, and test whether some families are more successful at establishing in non‐native regions than others. Location Hawaii, North America, Galapagos, Europe, South Africa, South Korea, Japan, Nansei Islands, Ogasawara Islands, Australia, New Zealand. Taxon Lepidoptera. Methods We compared numbers of non‐native, unintentionally introduced Lepidoptera species with the land area of 11 regions worldwide. Differences among native and non‐native assemblages in the distribution of species among families were investigated using ordination analysis. We tested whether invasion disharmony is explained by propagule pressure (proxied by species richness in border interceptions) and if families were associated with specific trade commodities. Results In total, 741 non‐native Lepidoptera species, accounting for 0.47% of the global diversity of lepidopterans, are established in at least one of the 11 regions. Crambidae, Pyralidae, Tineidae and Gracillariidae were particularly successful invaders, whereas the two most species‐rich families, Erebidae and Geometridae, were under‐represented among non‐native Lepidoptera. Much of the variation in species numbers in the native, and less so in the non‐native assemblages could be attributed to land area. Although native assemblages were similar among nearby regions, non‐native assemblages were not, suggesting geography had little effect on invasion disharmony. Comparison of established with intercepted species revealed that macromoth families were generally under‐represented in establishments, whereas several micromoth families were under‐represented in interceptions. This discrepancy may relate to greater detectability of larger species or high propagule pressure via associations with specific invasion pathways. Main conclusions Invasion disharmony in Lepidoptera appears to be driven by processes unrelated to the success of native assemblages. While native assemblages developed through long‐term evolutionary radiation, the composition of non‐native assemblages is driven by differential invasion pathways and traits affecting the establishment of founder populations that vary among families.

Insect invasions track a tree invasion: Global distribution of black locust herbivores

“…Variation among herbivore species in the extent of both their intra-and intercontinental invasion success most likely coincides with the phenomenon of 'invasion disharmony', where certain groups of insects are over-represented among non-natives, while others are under-represented. This phenomenon has previously been demonstrated for worldwide Coleoptera (Liebhold et al, 2021) and Lepidoptera (Mally et al, 2022) invasions. Among the North American native Robinia specialists, Megacyllene robiniae has spread the furthest beyond the black locust native range in the Nearctic, while it has not spread to any other biogeographic region.…”

Climate change impacts the risk of invasion of eucalypt pests in Brazil

“…Conversely, there can be various reasons why species may not spread into suitable areas. For instance, lepidopterous species from the Geometridae, including M. privata studied in this research, are not extensively represented among invasive species, and macromoths are underrepresented in pest establishments (Mally et al, 2022). On the other hand, species with continuous development are more likely to become invasive compared to species with diapause, which is the case with M. privata , P. atomaria , P. beata and P. cloelia (Carne, 1996; Steinbauer et al, 2004b; Yamoah et al, 2016).…”

Predicting Forest Pest Threats in Australia: Are Risk Lists Worth the Paper they’re Written on?

“…We found that Hemiptera are under-represented on risk lists compared with establishments, while cerambycid beetles and Lepidoptera are considered more of a risk to forestry than they have proven historically. Australia has very high diversity among native fauna of Lepidoptera, and among the lowest ratio of non-native to native Lepidoptera species in the world [38]. This apparent lower establishment rate may, in part, be driven by competitive exclusion (e.g.…”