Forest disturbance and the spread of invasive species disrupt diel activity patterns in New Guinea ant communities

Abstract Tropical ant species differ in their daily activity, yet it remains unclear whether diel foraging and species coexistence patterns differ between primary forests and environmentally altered, invasion‐prone secondary forests. We placed baits on the forest floor and trunks in Papua New Guinea to assess ant foraging activity in primary and secondary forests during day and night. Using species‐time networks, co‐occurrence null models and generalized linear mixed‐effects models (GLMMs), we tested for differences in diel community patterns across forest types and strata. Primary forests hosted more diurnal species and exhibited a significant diel foraging specialization. In contrast, secondary forests were less species‐rich, dominated by invasive ants and showed a random diel foraging pattern, with a greater number of species active at night. Mean ant abundance per bait was twice as high during the day as at night in both forest types, but this increase was stratum‐dependent and driven by different guilds: arboreal and terrestrial ants showed higher daytime abundances on trunks in primary forests, while semiarboreal ants did so across both strata in secondary forests. This effect diminished in secondary forests when only native species were considered. Species co‐occurrence patterns, however, remained strongly negative across forest types and time periods. We conclude that forest disturbance and the spread of invasive species simultaneously disrupt diel activity patterns in ant communities. The persistence of negative co‐occurrence across forests and diel periods indicates that these patterns are driven by environmental filtering rather than shifts in interspecific interactions.