The aim of this work was to determine the impact of specific hosts on a population of Mepraia spinolai (Porter) (Hemiptera, Reduviidae), a sylvatic vector of Chagas' disease in Chile. We assessed whether a recently introduced host could be an important epidemiological factor in maintaining Chagas' disease in Chile. The study stressed the variations in survival, individual weight and fecundity in the insect population when the vector was raised with a species-specific food supply. The study compared the European rabbit Oryctolagus cuniculus, introduced in Chile ≤ 150 years ago, with a wild endemic rodent, Octodon degus. Hosts were placed separately in experimental glass chambers. Groups of insects maintained with rabbits had greater fecundity than those raised with rodents, but both groups had similar survival times and average weights. Both O. degus and the European rabbit appear to be suitable hosts for M. spinolai, but the rabbit is better than the rodent. Additional research is needed to determine which factors of O. cuniculus produce the observed results.