Fig 1.
The mean parasite concentration in the excreted urine of Trypanosoma cruzi-infected Rhodnius prolixus maintained at (A) 26°C and (B) 28°C at different triatomine developmental stages.
The differences between developmental stages were analyzed by linear mixed-effects modeling, taking the individual triatomine as random factor. (A) Third instar nymphs compared with: fifth instar (p = 0.0302); and adult stage (p = 0.0337) (n = 19). (B) Fourth instar compared with: third instar (p = 0.0351); fifth instar, (p = 0.0181); and adult stage (p = 0.0191) (n = 20). Error bars represent the standard error of the mean.
Fig 2.
The mean unfed body weight of uninfected Rhodnius prolixus at different developmental stages and ambient temperatures.
The unfed body weight significantly increased with increasing triatomine developmental stage (p < 2e-16, n = 120), and triatomines kept at 30°C had the lowest unfed body weight (comparison with: the 24°C treatment, p = 0.00016; the 26°C treatment, p = 0.019; and the 28°C treatment, p = 0.012; n = 120 for all comparisons). The 24°C group had a significantly higher unfed body weight compared to the 28°C group (p = 0.02905). Error bars represent the standard error of the mean.
Fig 3.
The mean blood ingestion ratio of uninfected Rhodnius prolixus blood-fed at different developmental stages and ambient temperatures.
The blood ingestion ratio is the blood-fed body weight of each individual divided by its own unfed body weight immediately prior to blood-feeding. The blood ingestion ratio decreased with developmental stage (p = 6.9e-13, n = 111). Additionally, the triatomines kept at 26°C had the lowest blood ingestion ratio of all temperature treatments (comparison with: the 24°C treatment, p = 2.1e-05; the 28°C treatment, p = 2.5e-06; and the 30°C treatment, p = 0.00022; n = 111 for all comparisons). Error bars represent the standard error of the mean.
Fig 4.
The mean retention performance of uninfected Rhodnius prolixus at different triatomine developmental stages and ambient temperatures.
Retention performance measures the proportion of the weight of the blood meal ingested in the previous nymphal instar that is maintained as triatomine body weight in the next instar. The 30°C treatment had the lowest retention performance (comparison with: the 24°C treatment, p = 6.6e-13; the 26°C treatment, p = 3.5e-11; and the 28°C treatment, p = 1e-12; n = 94 for all comparisons). Additionally, retention performance decreased with developmental stages (p < 2e-16). Error bars represent the standard error of the mean.
Fig 5.
Survival rate of uninfected Rhodnius prolixus maintained at four different temperatures during the 293 days of the experiment.
The insects kept at 30°C had lower survival than those kept at 24°C and 26°C (p = 0.003 and p = 0.02, respectively, according to the Cox proportional hazards regression model). Overall, n = 120, with n = 30 per temperature treatment group.