Defying the superorganism: Harvestmen escape ant predation

Abstract

Predation is a key ecological interaction shaping community dynamics, yet the role of Opiliones in such interactions, particularly with predatory ants, remains poorly understood. In this study, we report laboratory and field encounters between Neotropical Opiliones from two suborders—Eupnoi (2 species, 1 family) and Laniatores (6 species, 5 families)—and predatory ants from the genera Camponotus, Eciton, Labidus, and Solenopsis. Contrary to expectations, Opiliones consistently evaded predation, both in natural settings across regions including the Colombian Andes, the Venezuelan Amazon, and in Uruguay under controlled laboratory conditions. We propose several hypotheses to explain this evasion: the hardness of the Opiliones' chitinous exoskeleton, immobility and chemical defenses, the latter being widely documented within the group. Contrary to expected, chemical defenses were apparently less frequently used than the other defensive strategies. These findings represent novel records of predator-prey interactions between Opiliones and ants in nature, providing a foundation for future research on defensive strategies in harvestmen and their interactions with potential predators.