Taste recognition in kissing bugs: from peripheral detection to feeding decisions.

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

Montevideo

Simposio; XII Congress International Society for Neuroethology; 2016

The abilityto discriminate between nutritive and harmful food is essential for animals?survival. Though olfaction contributes to find a potential food source from adistance, the taste sense works as a final control system driving foodacceptance or rejection. Rhodniusprolixus uses its taste system to examine a potential biting site first,and to assess the quality of ingested food then. We studied the role of salts andbitter compounds on the whole feeding process of Rhodnius, from site recognition to ingestion.The feedingperformance of Rhodnius was evaluatedwhile salts (NaCl, KCl) or bitter compounds (caffeine, quinine) were added overthe biting substrate or in the diet, and the ingested volume, electromiogramsof the cibarial pump and electrophysiological recordings of taste sensilla wereregistered. Additionally, the effect of amiloride (specific sodium-receptorblocker) in taste perception was studied. Rhodnius avoided feeding on an appetitive diet when thesubstrate was spread with high-salt levels or bitter compounds. Antiappetitiveresponses were also observed for diets with no-salt, high-salt and bittercompounds. The inhibition for salts was reversed by amiloride treatment.Electromiograms revealed different inhibitory mechanisms for the differentfeeding conditions. The targets of amiloride are taste receptors of theantennae, and probably internal epipharyngeal receptors as revealed the ectrophysiologicalrecordings.Our resultsconfirm the importance of the taste system for a blood-sucking insect, and showthe effect of salts and bitter molecules on their feeding decisions. Moreover,amiloride-sensitive salt receptors seem to be involved in salt recognition in Rhodnius.