Some factors can facilitate or prevent T. cruzi transmission, i.e. vector immunity. Our work has managed to detect a stronger immune response against T. cruzi II in R. prolixus saliva and haemolymph, compared to that of R. colombiensis. Proteins from both species’ saliva and haemolymph were analysed for studying factors which might have been involved in such response; most proteins were detected in both species’ haemolymph, thereby indicating common immune mechanisms. Three proteins having oxidative immune activity were only expressed in R. prolixus. Lipocalin diversity and abundance predominated in R. prolixus saliva; these proteins are involved in nitric oxide metabolism and their role in immunity could be key in host defence against T. cruzi. Recognising the components modulating parasite transmission in a vector helps in understanding how such factors act independently and how they would act synergistically against T. cruzi, thereby enabling us to establish tools regarding Chaga’s disease epidemiology, aimed at predicting T. cruzi distribution and creating transmission control mechanisms.