Taste aversion for salts and alkaloids: can kissing bugs discriminate them?

BARROZO, RB; MINOLI, S; MASAGUÉ, S

Foz Iguazu

Congreso; 32 Annual Meeting of the International Society of Chemical Ecology; 2016

The taste systemof animals can help them in making appropriate feeding decisions, favoring theingestion of nutritious foods and avoiding noxious ones. Although the kissingbug Rhodnius prolixus attains highepidemiological importance as vector of the Chagas disease, its taste sense isparticularly disregarded. The existence of phagostimulants such as ATP or lowdoses of salts has been already described. However, the existence of aversivegustatory compounds is by far less studied in haematophagous insects. In thiswork, we show in 2-choice experiments that bugs avoid substrates with high-saltconcentrations (sodium and potassium salts) or with alkaloids (caffeine andquinine, commonly named as bitter compounds). By applying an aversive operantconditioning we analyzed whether insects perceive salts and alkaloids asdifferent aversive compounds or if instead they are perceived as similar but withdifferent degree of aversiveness. First, we established that R. prolixus is capable of learning toavoid zones of an arena loaded with different aversive stimuli if they are punishedwith a mechanical disturbance. Second, we found that bugs are not capable todistinguish sodium from potassium salts. Likewise bugs cannot discriminate saltsfrom alkaloids. Our results suggest the existence of a common treatment ofaversive information (high-salt or alkaloids) with independence of the chemicalidentity of the stimuli. This kind of studies serves to gain more insight intothe taste sense of a blood-sucking model but also to know about their learningabilities.