Feeding response of haematophagous bugs Rhodinus prolixus and Triatoma infestans to saline solutions: a comparative study

A comparative study of the intake response to saline solutions was made in Rhodnius prolixus and Triatoma infestans by examining the effects of saline concentration and starvation period. Both species imbibed a 0.15 M NaCl solution in the absence of phagostimulants. Whereas third-instar larvae of T. infestans starved for 1 week since ecdysis ingested large quantities of saline, R. prolixus of the same stadium did the same only after a food deprivation time of between 8 and 16 weeks since ecdysis. Interspecific differences could be ascribed to distinct saline acceptance thresholds for the same food deprivation period. These differences are discussed in relation to the different ecological niches occupied by each species. Some features of the physiological mechanism related to saline solution response are also discussed.