Mosquitoes do not like bitter

LAZZARI, CL; ORTEGA-INSAURRALDE, I.; ESNAULT, J; COSTA, E; CRESPO, JE; BARROZO, R.B.

JOURNAL OF CHEMICAL ECOLOGY

SPRINGER

Lugar: Berlin; Año: 2024

0098-0331

Chemical repellents play a crucial role in personal protection, serving as essential elements in reducing the transmissionof vector-borne diseases. A biorational perspective that extends beyond the olfactory system as the classical target may bea promising direction to move. The taste system provides reliable information regarding food quality, helping animals todiscriminate between nutritious and potentially harmful food sources, often associated with a bitter taste. Understandinghow bitter compounds affect feeding in blood-sucking insects could unveil novel molecules with the potential to reduce bitingand feeding. Here, we investigated the impact of two naturally occurring bitter compounds, caffeine and quinine, on thefeeding decisions in female Aedes aegypti mosquitoes at two distinctive phases: (1) when the mosquito explores the bitingsubstrate using external taste sensors and (2) when the mosquito takes a sip of food and tastes it using internal taste receptors.We assessed the aversiveness of bitter compounds through both an artificial feeding condition (artificial feeder test)and a real host (arm-in-cage test). Our findings revealed different sensitivities in the external and internal sensory pathwaysresponsible for detecting bitter taste in Ae. aegypti. Internal detectors exhibited responsiveness to lower doses compared tothe external sensors. Quinine exerted a more pronounced negative impact on biting and feeding activity than caffeine. Theimplications of our findings are discussed in the context of mosquito food recognition and the potential practical implicationsfor personal protection.