Should I eat or should I not? Bitter perception in a blood-feeding insect

GINA B. PONTES; ISABEL ORTEGA; GABRIELA DE BRITO SANCHEZ; SEBASTIAN MINOLI; ROMINA BARROZO

Congreso; XXVIII Congresso anual de la sociedad Argentina de investigacion en neurociencias; 2013

Food quality assessment is associated to an animal decision about feeding or not. Once triatomines reach a potentially suitable host, they walk over their skin in search of a good quality substrate (skin recognition phase) and then they pierce the skin until a venule or arteriole is reached. Subsequently they suck a small quantity of blood initiating the sampling phase of food. We show here that the fine assessment of gustatory preferences in triatomines occurs during both, the skin recognition phase and the sampling phase, independently. Triatomines have taste sensilla localized in the tip antenna that serve to determine externally the gustatory nature of the substrate. These taste sensilla showed electrophysiological sensitivity to bitter compounds like caffeine (CAF) and quinine (QUI). In feeding experiments we found that by adding CAF or QUI to the membrane of an artificial feeder offering an appetitive solution prevents insects from feeding. Additionally, the addition of CAF or QUI into the appetitive solution but not to membrane also caused an inhibition of the feeding behaviour of bugs. This modulation seems to occur by means of internal taste receptors placed in their alimentary canal (the epipharingeal organ). Finally, by applying a cognitive approach, we found that both, skin recognition and sampling phases, are modulated by experience. Results presented here highlight the relevance of bitter taste perception in the modulation of the feeding behaviour of insects.