Exploring gustatory responses and feeding behavior in Aedes aegypti mosquitoes: Implications for vector control strategies

BOCHICCHIO, P.; BARROZO, R.B.

Congreso; VII Congress of the Latin American Association of Chemical Ecology; 2023

In all animals, taste perception functions as a crucial alert system, enabling the identification of nutrient-rich substances while also detecting potential threats, guiding acceptance or avoidance of a food source. Female Aedes aegypti mosquitoes conduct a gustatory assessment of their landing substrate, notably the host's skin, prior to initiating a blood-feeding event. This implies that biting and feeding are deterred when the substrate contains gustatorily aversive compounds, such as quinine or caffeine. Our study aims to identify molecules capable of disrupting the mosquito feeding process and to elucidate their mechanisms of action. We used mated female Ae. aegypti mosquitoes, which are driven to seek a host and engage in blood-feeding. By using an artificial feeder, we coated its feeding membrane with the compound of interest. Our experimental design allowed for the individual analysis of landing events on the membrane, biting attempts, and ingestion rates. Our findings reveal that treatment of membranes with the gustatory repellent quinine (100 mM) leads to a high frequency of landings without subsequent biting and feeding. Similarly, the TRPA1 agonist NEM (N-ethyl maleimide) (20 mM) elicits a repellent effect comparable to our positive control quinine. In contrast, no landing or feeding events were observed at the 100 mM dose of NEM. The lower doses of NEM (2 mM) did not deter landings. Although, compared to the controls, membranes treated with 2 mM NEM reduced the ingestion rate of mosquitoes. This observed negative impact on feeding is primarily attributed to the extended time that mosquitoes require to ingest on NEM-treated membranes rather than changes in their final body size. This research sheds light on the potential for targeted disruption of mosquito feeding by specific molecules, prompting further exploration of the underlying molecular mechanisms and the development of practical applications for mitigating mosquito-borne diseases.