Abstract Low dissolved oxygen concentrations present

numerous challenges for non-air-breathing aquatic or-ganisms. Amphibian larvae and their predators can re-spond to oxygen levels by altering their behavior and physiology, but the ecological consequences of these re-sponses are generally unknown. We conducted two labo-ratory experiments to study the effects of dissolved oxy-gen on respiratory behavior and susceptibility to preda-tion of larval bullfrogs (Rana catesbeiana). In the first, we exposed small, lungless tadpoles to a predatory sala-mander larva (Ambystoma tigrinum) under high and low oxygen conditions. More tadpoles were consumed in high oxygen tanks than in low ones, presumably because salamanders remained near the surface in the low oxygen tanks while most tadpoles rested on the bottom. Tadpole activity depended on both oxygen and predator presence: swimming decreased after addition of salamanders under high oxygen, but increased under low oxygen. In the sec-ond experiment, we examined the effect of predator chemical cues on the air-breathing rate of large tadpoles with well-developed lungs under low oxygen conditions. In the presence of chemical cues produced by dragonfly larvae consuming bullfrog tadpoles, air-breathing and swimming were significantly reduced relative to con-trols. These experiments demonstrate the potential im-pact of dissolved oxygen on predator-prey interactions, and suggest that outcomes depend on the respiratory ecology of both predator and prey. Key words Air-breathing · Rana catesbeiana · Dissolved oxygen · Ambystoma tigrinum · Hypoxi