[Influence of temperature and humidity on the nymphal development of Rhodnius robustus].

Objective: To assess the significant differences in the nymphal development of the Rhodnius robustus Larrousse, 1927 under different temperatures and humidity conditions. This is a species found in the northern region of Brazil (states of Acre, Amazonas, and Pará), Colombia, Equator, Peru and Venezuela.
Methods: Three groups of triatominae were kept under the following laboratory conditions: 33/40 (33+1 degree C and 40+/-5% of relative humidity - RH), 33/70 (33+/-1 degree C and 70+/-5% RH), and 28/70 (28+/-1 degree C and 70+/-5% RH). The incubation period of the eggs, developmental time of each stage, mortality percentage, number of bloodmeals, and the total amount of time from the egg hatching to adult ecdysis were observed.
Results: The shortest average time of nymphal development was observed in the 28/70 group, with following averages: 14.4, 17.3, 20.3, 22.8, and 40. Significant differences were observed in the embryonic development between the groups (p<0.01). For all groups, the number of bloodmeals had a gradual increase near the adult phase, except for the 3rd instar of the 33/70 group. The smallest mortality percentages were seen in the 28/70 group.
Conclusions: High temperatures, regardless of the humidity, can accelerate the biological development cycle of R. robustus. However, these temperatures can impair the colonies' survival, preventing their maintenance in the laboratory.