Epsilon Archive for Student Projects

Abstract

The sugar feeding behaviour of mosquitoes plays an essential role in their survival, reproduction, and vector competence. This project focuses on the role of the gustatory receptor gene Gr5 of Aedes aegypti in sugar detection. Understanding how mosquitoes assess and respond to different sugars can provide insight into the evolution of sugar receptors in Ae. aegypti and improve vector control strategies. In this project, a modified FlyPAD system was applied to access the feeding behaviour of two wildtype Aedes aegypti strains, Liverpool and Rockefeller, and a Gr5 gene knockout mutant, ΔGr5, when provided with sucrose, glucose, fructose and trehalose at a series of concentrations containing dye. The feeding dynamics were recorded and defined as different feeding events. Food imbibed was quantified using a spectrophotometer and dye-based standard curves. Results showed that both wildtype strains exhibited similar sugar feeding dynamics, with maximum feeding around 100 mM. In contrast, the ΔGr5 line demonstrated a marked reduction in feeding across all sugars, particularly sucrose and trehalose, and a lack of a significant dose response. The ΔGr5 line displayed altered feeding dynamics for sucrose and trehalose, shifting from a sip-driven pattern to a “burst-pause” pattern. Statistical analyses revealed that Gr5 knockout significantly disrupted the coordination of feeding parameters, especially for disaccharides.

The data suggest that Ae. aegypti Gr5 has a possible function of detecting disaccharides. And Gr5 might contribute to the formation of the Ae. aegypti gustatory receptor tetramer as a monomeric subunit. For a future step, crossing Ae. aegypti ΔGr5 with different Gr knockout mutant lines, followed by comparative feeding assays of sucrose, glucose, fructose, and trehalose, is expected to reveal further details of the sugar-detection function of the Gr5 receptor in Ae. aegypti.