Triatomines (kissing bugs) are hematophagous insects responsible for the transmission of Chagas disease. Due to their crepuscular and nocturnal habits, they have historically been considered as non-visual animals. However, some simple visual behaviors have been described in these insects (such as negative phototaxis and orientation to point light sources), and their compound eyes and ocelli are known to exhibit morphological changes in response to light, which would allow them to adapt to variable environmental conditions. Our overall objective is to understand how these insects perceive their visual environment and in which biological contexts vision is relevant to them. Here, we show that Rhodnius prolixus consistently responds to looming visual stimuli by either freezing or escaping, and it can rapidly alternate between these behaviors based on the ongoing stimulus information. We observed that escape responses are primarily evoked by stimuli that mimic the approach of a predator at a constant speed. Our results demonstrate a clear role of the visual system in mediating the defensive behaviors of triatomines. Similar to what has been observed in other highly visual arthropods, the probability of occurrence and intensity of these responses depend on the evaluation of the risk that the visual stimuli entail. Our study opens the question of how triatomines can solve the computational tasks supporting these visual capabilities with a reduced visual system.