Death by a Thousand Ants: Predation on Grasshoppers by Invasive Ants in a Grassland

Invasive ants are among the most ecologically disruptive taxa worldwide, often exerting high predation pressure that drives declines in native ant and arthropod diversity. Although their impacts on litter-dwelling assemblages are well documented, effects on large, mobile aboveground insects remain poorly understood. Here, we report predation by the invasive tawny crazy ant (Nylanderia fulva) on adult grasshoppers in a coastal tallgrass prairie in Texas. In tethering experiments, nearly half of grasshoppers (48.7%) were killed and consumed by N. fulva within 24 h, demonstrating their collective ability to subdue large herbivores. Complementary stable isotope analyses placed N. fulva at an intermediate trophic position (mean = 2.30), consistent with an omnivorous diet dominated by plant- and honeydew-derived resources but supplemented opportunistically by animal prey. These findings extend the known ecological impacts of N. fulva, suggesting that predation on grasshoppers may further alter plant-herbivore interactions and threaten the conservation of imperiled tallgrass prairies. Our results highlight the importance of considering both litter and aboveground arthropod communities when assessing the ecological consequences of invasive ants.