Abstract: Because antipredator behaviors such as increased refuge use and decreased activity bear the costs of decreased feeding efficiency and growth rates, fitness is maximized if they are exhibited only in the presence of a predator. Detection of heterospecific predators often occurs through the recognition of chemical or visual cues. Chemical cues have been shown to be important in generating a response to conspecific predators in systems that include a cannibalistic adult feeding on juveniles. In systems in which juveniles feed on other juveniles, however, the difference in chemical cues may not be substantial enough to trigger antipredator behavior. In this study we test whether chemical cues, visual cues, or a combination of both cues are important for the detection of conspecific predators in the larvae of the dragonfly Plathemis lydia. Individuals were exposed to chemical cues, visual cues, and a combination of both cues from larger conspecifics while their activity and feeding rates were observed. Individuals were also exposed to no predator controls and heterospecific predator controls with which to compare the responses to conspecific predators. Although P. lydia did show an antipredator response to heterospecific predators, the responses to visual and chemical cues from conspecific predators were more consistent with a competitive response. Stronger responses were shown to chemical or visual cues alone than to a combination of cues.