Observaciones sobre capacidad alimenticia y respiración de Triatoma infestans y Rhodnius prolixus (Hemiptera, Reduviidae)

Abstract

The authors have studied the amount of blood ingested, the loss of weight after a blood meal and the respiratory metabolism of 5th instar nymphs of Triatoma infestans and Rhodnius prolixus. T. infestans ingests from 300 to 400 mg of blood and R. prolixus 180 to 190 mg (4.1 and 6.4 times their initial weights, respectively). Weight decreases markedly in both specie during the first three hours after the meal. This loss represents from 15 to 30% of the weight of the insects after feeding. Oxygen consumption and CO2 production are greater in the larger species. Right after a blood meal the gas exchanges increase from 3 to 6 fold. Starving insects, free to move in the flask, respired more oxygen only in the case of T. infestans; CO2 production was not increased. Gauze-restrained insects of either species showed an increase in respiration starting on day 4th after the blood meal. Contrary to espectation the gauze apparently acted as a mechanical stimulus to movement. Respiratory activity tended to return to the initial values during the 3d. week after the meal in T. infestans. This seem to be correlated with the need for a second blood meal by this species before reaching the adult stage. R. prolixus metabolism remains higher, reflecting the ability of Rhodnius nymphs to transform into adults within a month after a single blood meal. Respiratory quotients were higher in the gauze-restrained insects during starvation and right after the blood meal, especially in T. infestans.