Predator Loss Drives Functional Shifts in Termite-Mediated Wood Decomposition in Tropical Forests

Termites play a critical role in wood decomposition and nutrient cycling in tropical forests, yet the ecological consequences of predator loss on termite-driven processes remain poorly understood. Here, we examined how the absence of the Northern Tamandua, a specialized termite predator, affects termite spatial ecology and wood consumption in Panama. We compared colony density, nest characteristics, and wood consumption rates between predator-free and predator-present habitats using arboreal termites as focal taxa (Microcerotermes arboreus and Nasutitermes spp.). We found that predator-free sites exhibited significantly higher termite nest density, lower nest height, and greater wood consumption than predator-present sites. For instance, nest height increased nonlinearly with canopy height, indicating that nest placement is shaped by behavioral factors beyond tree structure, possibly including predation risk. In contrast, nest volume did not differ between habitats, indicating consistent investment in nest construction regardless of predator presence. Despite being the most frequent termite in wooden blocks, M. arboreus showed similar colonization rates across both habitat types, implying that increased wood consumption in predator-free areas was not driven by species turnover but by increased foraging activity, a result of partially higher colony density. Wood consumption also showed a non-linear relationship with nest density, increasing up to intermediate densities and declining thereafter. Our findings demonstrate that the loss of a vertebrate predator can cascade through detritivore communities and alter fundamental ecosystem processes such as wood decomposition and carbon flux. This study underscores the importance of trophic interactions in shaping below- and above-ground processes in tropical forests, and the ecological consequences of defaunation.