Single-Sensillum Taste Recordings in Mosquitoes

Abstract

In insects, gustatory neurons sense chemicals upon contact and directly inform many behaviors critical for survival and reproduction, including biting, feeding, mating, and egg laying. However, the taste sensory system is underexplored in many anthropophilic disease vectors such as mosquitoes, which acquire and transmit human pathogens during blood feeding from human hosts. This results in a big gap in vector biology—the study of organisms that spread disease by transmitting pathogens—because insect vectors closely interact with humans while selecting suitable individuals and appropriate bite sites for blood meals. Human sweat and skin-associated chemistries are rich in nonvolatile compounds that can be sensed by the mosquito's taste system when she lands on the skin. Taste sensory units, called sensilla, are distributed in many organs across the mosquito body, including the mouthparts, legs, and ovipositors (female-specific structures used to lay eggs). Each sensillum is innervated by as many as five taste neurons, which allow detection and discrimination between various tastants such as water, sugars, salts, amino acids, and plant-derived compounds that taste bitter to humans. Single-sensillum recordings provide a robust way to survey taste responsiveness of individual sensilla to various diagnostic and ecologically relevant chemicals. Such analyses are of immense value for understanding links between mosquito taste responses and behaviors to specific chemical cues and can provide insights into why mosquitoes prefer certain hosts. The results can also aid development of strategies to disrupt close-range mosquito–human interactions to control disease transmission. Here we describe a protocol that is curated for electrophysiological recordings from taste sensilla in mosquitoes and sure to yield exciting results for the field.