Bitter taste perception in the blood-sucking insect Rhodnius prolixus

ORTEGA INSAURRALDE, ISABEL; PONTES, GINA; BARROZO, ROMINA

Huerta Grande, Córdoba

Congreso; 2do Congreso de la Asociación Latinoamericana de Ecología Química; 2012

Asociación Latinoamericana de Ecología Química

The taste sense plays a crucial role in animals´ life informing them about the nutritional quality of a food source. Moreover it provides a means of discrimination between nutrient-rich substrates, from harmful, mostly bitter-tasting. Rhodnius prolixus is a hematophagous insect that feeds on blood from small vessels of vertebrate hosts. Once insects pierced the host skin, they move their mouthparts until a venule or an arteriole is reached. Insects pump a small quantity of blood initiating the sampling phase of food, which lasts ca 1-3 min. During this period, the absence of a phagostimulant would prevent insects from continuing with the feeding process. Therefore the taste sense might become crucial in terms of the assessment of food quality during this phase: A candidate to do this task would be the epipharingeal organ located in the food canal. Our goal in this work was: 1- to determine which compounds or taste modalities (salty, sweet, bitter, monosodium glutamate) are perceived by bugs (beyond the well-known phagostimulant ATP); 2- to analyze whether mixtures of tastant could enhance or inhibit the feeding behavior of bugs. The feeding response of bugs was analyzed by measuring the weight gain of insects to different test diets in an artificial feeder set-up during 10 min. Our results show that R. prolixus can perceive different taste modalities like bitter substances, salts and disaccharides in dose-dependent manner, although this was only evident in the presence of ATP. Notably, bitter compounds have an inhibitory effect on the feeding behavior of bugs. The importance that the taste sense plays in the feeding behavior for one of major vector of Chagas disease in Latin America begins to be understood.