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 h umidity conditions This is a species found in the northern region of Brazil (states of Acre, Amazonas, and Para), Colombia. Equator, Peru and Venezuel a. Methods Three groups of triatominae were kept under the following laborator y conditions: 33/40 (33+1 degreesC and 40+/-5%) of relative humidity - RH), 33/70 (33+/-1 degreesC and 70+/-5% RH), and 28/70 (28+/-1 degreesC and 70/-5% RH). The incubation period of the eggs, developmental lime of each sta ge, mortality percentage, number of bloodmeals, and the total amount of tim e from the egg hatching to adult ecdysis were observed Results The shortest average time of nymphal development was observed in th e 28/70 group. with fiollowing averages: 14.4, 17.3, 20.3, 22.8, and 40. Si gnificant differences were observed in the embryonic development between th e 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 t he biological development cycle of R. robustus. However, these temperatures can impair the colonies' survival,pre venting their maintenance in the lab oratory.