Figure 2. Olfactory conditioning with arabinose or xylose supplemented with nutritious sorbitol forms robust 24hr memory.

(A) Sorbitol, maltodextrin and sucrose support fruit fly survival for several days. The number of flies alive on sorbitol or maltodextrin was statistically indistinguishable to those on sucrose at all time points (p>0.07) except at 84hr where maltodextrin was different to sucrose (p=0.03, asterisk). Survival on sorbitol, maltodextrin and sucrose was statistically different to on water at all time points (all p<0.01). Data are mean ± SEM. n=10 for each data point.

(B) Sucrose and maltodextrin elicit robust proboscis extension behavior but sorbitol does not. Flies were presented with 3M solutions of sucrose or sorbitol or 1.25M maltodextrin to the front leg. Performance of sorbitol exposed flies is statistically different from other groups (p<0.01, chi-squared test, marked by asterisk). n≥20 flies for each sugar.

(C) Training with sorbitol supplemented arabinose forms persistent memory. 24hr appetitive memory performance of flies trained with sorbitol supplemented arabinose is not significantly different to flies trained with sucrose (p>0.6). Asterisks denote significant difference between marked groups and others (p< 0.05, arabinose; p<0.01 sorbitol, ANOVA). Data are mean ± SEM. n≥14.

(D) Training with sorbitol supplemented xylose forms persistent memory. 24hr appetitive memory performance of flies trained with sorbitol supplemented xylose is not significantly different to flies trained with sucrose (p>0.6). Asterisks denote significant difference between marked groups and others (p <0.05, xylose; p<0.01 sorbitol, ANOVA). Data are mean ± SEM. n≥14.

(E) More dyed sorbitol is consumed in 5min when mixed with arabinose or xylose. Each substance or combination was mixed with dye and presented dried on filter paper in the conditioning apparatus. The amount ingested with arabinose+sorbitol or xylose+sorbitol was statistically different to sorbitol (p<0.05 and p<0.01 respectively) or water alone (both p<0.01, ANOVA). Consumption of dye with sorbitol was not statistically different from dye with water (p>0.05). Data are mean ± SEM. n≥8.