Arthropod diversity dynamics in guava and cherimoya plantations affected by Solenopsis invicta invasion.

The red imported fire ant (Solenopsis invicta, RIFA) is one of the most ecologically disruptive invasive species, yet its impacts on arthropod biodiversity within subtropical orchard agroecosystems-particularly guava (Psidium guajava) and cherimoya (Annona cherimola) plantations-remain insufficiently quantified. This study investigated how RIFA invasion influences arthropod community composition, diversity and trophic group dynamics across these 2 plantation systems in southern China. Results indicated that RIFA invasions significantly reduced both order- and family-level richness and evenness. Arthropod order richness declined markedly in invaded areas, with only 8 orders detected in invaded cherimoya plots compared to 11 in non-invaded plots. At the family level, diversity decreased by 75% in guava plantations (from 8 to 2 families) and by 60% in cherimoya plantations (from 10 to 4 families). In invaded plots, RIFAs constituted over 80% of the total arthropod population. Hedges' g effect sizes further revealed substantial increases in overall arthropod abundance (+277.62%) and RIFA-specific abundance (+357.42%), coupled with significant declines in family richness (-16.29%) and non-RIFA arthropod abundance (-22.78%). Piecewise structural equation modeling indicated that RIFA exerted strong, negative impacts on detritivores and omnivores, while herbivores were less affected, indirectly suppressing predators by reducing their prey base. Collectively, these findings suggested that RIFA invasion drove pronounced taxonomic homogenization, functional simplification and trophic imbalance within agricultural landscapes. Effective, long-term monitoring and biodiversity-focused management strategies are urgently needed to mitigate the ecological degradation driven by RIFA invasions in these critical agroecosystems.