Tasting the word by a blood-sucking insect

BARROZO RB; PONTES G; CANO, A; MINOLI, S; MASAGUE, S; GUTIERREZ, L

Congreso; 14th European Symposium for Insect Taste and Olfaction; 2015

The ability to discriminate betweennutritive and harmful food is essential for animals? survival. Though olfactioncontributes to find a potential food source from a distance, the taste senseworks as a final control system driving food acceptance or rejection.Triatomines are blood-sucking insects, vectors of Chagas Disease in LatinAmerica. As soon as they reach a potential vertebrate host, they walk overtheir skin searching for an adequate site to pierce. Then, they take a firstsampling gorge to decide if food is acceptable or not. Our work shows that in triatomines,feeding can be inhibited during the gustatory assessment of both, the surfaceto bite or the first gorge of food. Insects can detect bitter compounds andhigh salt concentration and both processes can prevent them from feeding.Morphological inspections along with electrophysiological recordings confirmthat the sensory organs involved in taste detection are located in the antennaand in the pharynx. These two independent sensory stages work with differentthresholds of response: internal sensors are by far more sensitive to detectaversive compounds than external ones. Additionally, applying amultiapproach strategy, we study whether bugs are able to discriminate amongaversive stimuli, or alternatively if they are simply indistinguishablenegative input signals that induce feeding inhibition. On the one hand wetarget on the putative salt receptors studying the transduction pathwaypossibly involved in the aversive detection. On the other hand, we use acognitive approach to gain more insights on the ability of insects tobehaviorally discriminate among aversive taste modalities. We also study theeffects of previous gustatory experiences on feeding. Our results highlight therelevance of taste perception of aversive compounds in modulating the feedingbehavior in a blood-sucking insect and the importance of previous experience inthe final feeding decision.