Development of Rhodnius prolixus (Hemiptera: Reduviidae) under constant and cyclic conditions of temperature and humidity

RESUMO

Development of Rhodnius prolixus after eclosion until the adult stage was studied at constant temperatures (T), 15, 20, 25, 28, 35ºC, 20/25ºC, 25/35ºC, and relative humidities (RH), 75, 86 and 97 (por cento) and fluctuating (16/8 hr) temperatures, T I/II, 15/28ºC, 25/28ºC and 25/35ºC, and relative humidities, RH I/II, 86/75 (por cento) and 97/75 (por cento). Eclosion or molting were not observed at 15ºC and 86 or 97 (por cento) RH, respectively. At 35ºC and 75 (por cento) RH only few insects molted. By alternating T I/II, 15/28ºC and 25/35ºC, insects developed at high frequency. Cumulating the average lengths of the interphases within independent groups for each instar, R. prolixus reached the adult stage most rapidly (86.7 days) and at highest frequency per instar (mean 91.8 por cento) at 28ºC and 75 (por cento) RH. Under fluctuating T I/II, development was completed within 100 days or less at 25/28ºC and 20/25ºC (>185 days), and at constant 20ºC (>300 days). Mortality was higher at constant 97 (por cento) RH or fluctuating RH I, 97 (por cento) than at constant or fluctuating 86 (por cento) RH. Refeeding was minimal at optimal conditions of T and RH for development. The most refeeding was observed at a constant 35ºC.