Sugar discrimination and gustatory thresholds in captive-born frugivorous Old World Bats

In general, preference for different sugars in nectarivores and frugivores is related to the composition of their food. We determined individual prefe rences in Cynopterus brachyotis and Pteropus rodricensis, and group prefere nces in one group of P. rodricensis and two mixed groups of P. rodricensis, P. pumilus, P. vampyrus, and P. hypomelanus. Most bats were born in captiv ity and received a diet with a composition of sugars of sucrose = glucose > fructose during 1 to 6 years before the experiment. We tested the hypothes is that diet composition influences food preferences, and predicted that ba ts would not discriminate between sucrose and glucose, and would prefer suc rose and glucose over fructose. Individuals and groups consistently favored sucrose over glucose and fructose, and fructose over glucose. We also dete rmined gustatory thresholds for (0.15% weight/weight) than fructose (> 0.5% ) and glucose (0.5%). Food preferences, in general, did not match the compo sition of the diet. Gustatory thresholds may be a valid proximate reason to explain preference for sucrose over glucose and fructose, but not for pref erence for fructose over glucose.