Removal of Pheidole megacephala (Hymenoptera: Formicidae) facilitates partial recovery of native ants and predatory arthropods in secondary forest

Invasive ants often exert strong negative effects on native ant assemblages and other invertebrates through strong resource monopolization and chemical defense. Removal of an invasive ant may therefore promote recovery of local biodiversity. However, evidence for such effects is mixed, and often taxon-specific. In this study, we experimentally removed Pheidole megacephala (Hymenoptera: Formicidae) from 2 secondary forest sites at located at Taiping (TP) (herein referred to as TP1 and TP2) and examined the taxon-specific responses of native ants, beetles, and spiders under field conditions. Removal of P. megacephala had limited effects on ant species richness and Shannon diversity. In contrast, beetle family richness at TP1 increased significantly during the first year of posttreatment compared with pretreatment levels. Several native ant species (eg Carebara diversa, Recurvidris recurvispinosa, and Solenopsis indagatrix) and predatory beetle taxa (Harpalinae, Cetoniinae, Paederinae, and Staphylininae) that were absent before treatment were detected following P. megacephala removal. Spider family richness declined during the second year of posttreatment at TP2, whereas the activity density of hunting spiders, particularly Ctenidae, Oonopidae, and Salticidae, increased approximately 2-fold at TP1 after removal. These native ants, predatory beetles, and hunting spiders that responded positively to removal share similar food resources or overlapping nesting and foraging habitats with P. megacephala. Our results suggest that removal of this invasive ant may have facilitated partial recovery of the local invertebrate community, particularly taxa that are ecologically and behaviorally similar to P. megacephala, likely by releasing food and spatial resources.