Salts control feeding decisions in a blood-sucking insect.

PONTES, G; PEREIRA, MH; BARROZO, RB

JOURNAL OF INSECT PHYSIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2017 vol. 98 p. 93 - 100

0022-1910

Salts are necessary for maintaining homeostatic conditions within the body of all living organisms. Likewith all essential nutrients, deficient or excessive ingestion of salts canresult in adverse health effects. The taste system is a primary sensorymodality that helps animals to make adequate feeding decisions in terms of saltconsumption. In this work we show that sodium and potassium chloride salts modulatethe feeding behavior of Rhodnius prolixusin a concentration-dependent manner. Feeding is only triggered by an optimal concentrationof any of these salts (0.1 - 0.15 M) and in presence of the phagostimulant ATP.Conversely, feeding solutions that do not contain salts or have a high-saltconcentration (> 0.3 M) are not ingested by insects. Notably, we show that feedingdecisions of insects cannot be explained as an osmotic effect, because theystill feed over hiperosmotic solutions bearing the optimal salt concentration.Insects perceive optimal-salt, no-salt and high-salt solutions as different gustatoryinformation, as revealed the electromyogram recordings of the cibarial pump. Moreover,because insects do a continuous gustatory monitoring of the incoming foodduring feeding, sudden changes beyond the optimal sodium concentration decreaseand even inhibit feeding. The administration of amiloride, a sodiumchannel blocker, noticeablyreduces the ingestion of the optimal sodium solution but not of the optimalpotassium solution. Salt detection seems to occur at least through two saltreceptors, one amiloride-sensitive and another amiloride-insensitive. Ourresults confirm the importance of the gustatory system in R. prolixus, showing the relevant role that salts play on theirfeeding decisions.