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

PONTES G; ORTEGA INSAURRALDE I; BRITO SANCHEZ G; MINOLI SA; CANO A; SFARA V; MOUGABURE CUETO G; BARROZO R.

Simposio; XIII European Symposium for Insect Taste and Olfaction; 2013

Taste sense delivers reliable information about the quality of feeding sources, providing an adative tool to discriminate nutrients from harmful substrates. So, food quality recognition followed by an associated decision making acquires important physiological consequences for animals. Triatomine insects (vectors of Chagas Disease in Latin America) feed on blood from small vessels of vertebrate hosts. Once they find a potentially suitable host (mainly by olfactory and thermal cues), they pose over the host skin (skin recognition phase) and pierce it with their proboscis until a venule or arteriole is reached. Next, they suck a small quantity of blood initiating the sampling phase of food. If the sampled diet fulfils bug?s feeding requirements, the insect will continue with the ingestion of food. So far, no information is available about fine discrimination of gustatory preferences in triatomines and how different tastants might be modulating the decision making during the skin recognition phase and the sampling phase. We started filling a gap of knowledge on the ultrastructure of taste organs and their physiological and behavioural responses to relevant substances of bugs? diet. Taste perception in triatomine bugs leading to aversiveness or acceptance of a food source is dependent on chemical identity of tastants -salts, ?bitter? compounds, ATP- and other chemical and physical qualities like concentration, osmolarity, pH, ionic composition, nitric oxide levels. The skin recognition phase was observed to occur via the contact chemoreception of chaetic sensilla located in the antenna while the sampling phase seems to occur in internal receptors placed in their alimentary canal (the epipharingeal organ). Additionally, applying a cognitive approach; we found that these two independent processes are modulated by experience.