The impact of invasive spotted lanternfly (Lycorma delicatula) on U.S. Hymenoptera community composition

The spotted lanternfly (SLF, Lycorma delicatula) is an invasive planthopper (Fulgorid, Hemiptera) from Asia that has spread across the eastern United States since its introduction to Pennsylvania in 2014. While the plant damage caused by SLF honeydew excretions is well documented, its potential to alter local insect communities is not well understood. In this study, we investigated whether increased SLF population affects local Hymenoptera community composition in Eastern U.S. forests. We hypothesized that higher SLF abundance would attract more honeydew-feeding Hymenoptera, including ants (Formicidae), bees (Apidae), and wasps (Vespidae). Twelve forested study sites across an invaded region in Virginia and West Virginia were selected based on a visually surveyed SLF abundance gradient, and they were sampled biweekly during the 2022 growing season using sweep netting, pitfall traps, and blue-vane flight-intercept traps. We identified 6500 Hymenoptera samples to the family level and analyzed them using generalized linear mixed models to assess the effects of SLF abundance on Hymenoptera family richness, total abundance, and within-family abundance. Environmental variables, including temperature and canopy cover, were included as covariates. Hymenoptera abundance increased with SLF biomass, while family richness was unrelated to biomass but increased with temperature. Select families (Bethylidae, Encyrtidae, Vespidae) responded positively to SLF biomass increase. The increases in these groups may indicate a shift in resource use and a potential increase in dangerous families, such as stinging Vespidae, due to the ongoing SLF invasion. Given the ecological importance of Hymenoptera, including as pollinators, our findings show that the SLF invasion is altering U.S. insect communities, potentially driving cascading ecosystem effects.