Effects of fasting on the interplay between temperature and Trypanosoma cruzi infection on the life cycle of the Chagas disease vector Rhodnius prolixus

Rhodnius prolixus, a triatomine insect, is one of the most important vectors of Chagas disease in South America. Its interaction with the parasite Trypanosoma cruzi, the causative agent of this disease, is known to be deeply affected by ambient temperature and the nutritional status of the insect vector. In this study, we investigated how starvation affects the life cycle of R. prolixus and the population dynamics of the parasite inside the intestine of the vector at four temperatures ranging from 24°C to 30°C. The weights and molting times of chronically infected and uninfected insects were monitored through repeated 30-day fasting periods from first instar to adult stage, assessing their capacity to retain blood meal weight between developmental stages and tracking parasite concentrations in their urine. Our results demonstrate that ambient temperature is a crucial factor affecting the resistance of R. prolixus to starvation, as survival, body weight, and weight retention greatly decreased in high temperature treatments. Furthermore, we showed that temperature significantly influenced whether T. cruzi established an infection in early instars, with few insects developing infections at the lowest and highest temperature treatments. Additionally, we discovered that a fasting period of 30 days induces a steady decrease in parasite populations in the vector over its lifetime. Infection by T. cruzi had no effect on the survival, molting time, and nutritional factors monitored in our protocol. Our results highlight the importance of nutrition as a determining factor for the development of the vector and the parasite, providing valuable insights for elucidating the complex interplay between temperature and nutrition in shaping the epidemiology of Chagas disease in a changing climate.