What do taste receptors tell blood-sucking bugs about food quality?

PONTES, GINA; ORTEGA INSAURRALDE, ISABEL; DE BRITO SANCHEZ, GABRIELA; BARROZO, ROMINA

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

Chemosensory systems like smell and taste are essential senses for most animals to find food, locate a sexual partner and refuge. Though, taste sense enables them to detect safe-nutritious food sources and to avoid toxic substances present in the environment. Taste receptors in insects are widely distributed over the animal`s body (antenna, proboscis, legs, ovipositor, wings). In triatomine insects, previous reports based on morphological evidences, have suggested the presence of taste receptors on the antenna, although also on the proboscis. However, the functional nature of these receptors was still unknown. In the present work, we characterized through single sensillum recordings (SSR), the response of taste antennal sensillainRhodniusprolixusto different tastants, like salts (NaCl, KCl), sweet (sucrose) and bitter compounds(quinine and caffeine). Subsequently, we analyzed,by means of behavioral assays, whether the taste antennal/proboscis receptors might have a role in food acceptance. The feeding response of insects (measured as weight gain) to a well-established artificial diet (i.e. saline solution added with ATP,adenosine triphosphate) was evaluated in insects that their antenna or proboscis had been previously and gently touched with a toothpick soaked with water, NaCl,quinine or caffeine: Our results revealthe existence of taste receptors sensitive to salts andbitter compounds, (caffeine and quinine)that respond in a dose-dependent manner. Furthermore, we begin to uncover the role of taste antennal/proboscis receptors in the decision of insects to accept or to reject a potential meal.