Trypanosoma cruziinfection reduces the population fitness ofMepraia spinolai, a Chagas disease vector

Abstract

AbstractThe hematophagous insectMepraia spinolai(Hemiptera: Reduviidae: Triatominae) is naturally infected with the protozoan parasiteTrypanosoma cruzi, the agent of Chagas disease in humans. In this study, we compared the demographic parameters ofM. spinolaiwith and withoutT. cruziinfection. We collected the immature life table data of 479 M. spinolaiindividuals of control cohort (reared on mice withoutT. cruziinfection) and 563 M. spinolaiindividuals of treatment cohort (reared on mice withT. cruziinfection). Nymphs were maintained in individual compartments inside a growth chamber (26°C; 65–75%) until adult emergence; moulting and survival were recorded daily. For the adult life table study of the control, we used 24 pairs of adults from the control cohort. For the adult life table study ofT. cruzi‐infected cohort, 25 infected females were paired with 25 males from the control cohort. Life table data were analysed using bootstrap‐match technique based on the age‐stage, two‐sex life table. The preadult survival rate (0.5282) of the control cohort was significantly higher than that of the infected cohort (0.2913). However, the mean fecundity of reproductive females (Fr = 22.29 eggs/♀) and net reproductive rate of population (R0 = 5.07 offspring/individual) of the 0.5th percentile bootstrap‐match control cohort were not significantly different from those of the infected cohort (Fr = 23.35 eggs/♀,R0 = 3.77 offspring/individual). Due to the shorter total preoviposition period and higher proportion of reproductive female, the intrinsic rate of increase (r = 0.0053 d−1) and finite rate of increase (λ = 1.0053 d−1) of control cohort ofM. spinolaiwere significantly higher than those of theT. cruzi‐infected cohort (r = 0.0035 d−1, λ = 1.0035 d−1). These results suggest thatT. cruziinfection reduces the population fitness of the Chagas disease vectorM. spinolai.