Gr64a1 mutants exhibit a statistically significant reduction in the response to sucrose, maltose, maltotriose, fructose and glycerol. However, responses to trehalose, melezitose, m-glucoside, and glucose are unaffected.
The L-type labellar sensilla of homozygous, Gr64a1/Df(3L)Gr64a2 and Gr64a1/Df(3L)GN34 flies show almost no electrophysiological response to either maltotriose, stachyose, raffinose, leucrose or fructose. The response to sucrose, maltose, turanose, maltitol and palatinose is reduced compared to wild type, but not abolished. The response to m-α-glucoside, glucose and melezitose is not reduced in the mutant flies, and the response to glucose may be somewhat elevated.
The mean proboscis extension response of homozygous flies to fructose, stachyose, maltotriose, maltose and sucrose is reduced compared to controls, but the response to glucose, melezitose and m-α-glucoside is not affected.
The number of proboscis extension responses in 30 seconds in a walking proboscis extension assay is severely reduced in Gr64a1/Df(3L)Gr64a2 flies compared to controls in response to either maltotriose or sucrose.