KORINE, CARMI ; SANCHEZ, FRANCISCO; PINSHOW, BERRY; DUDLEY, ROBERT; Ben-Gurion Univ. of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel; Ben-Gurion Univ. of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel; Ben-Gurion Univ. of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel; Dept. of Integrative Biology, Univ. of California, Berkeley, CA, USA: The role of ethanol as an olfactory cue and as an appetitive stimulant in the Egyptian fruit bat, (Rousettus aegyptiacus)

Ripe, fleshy fruits make up much or even all of the diet of many mammals, birds, and insects that may also effect seed dispersal. Sugars in fruit are an important source of energy for frugivorous animals, but these carbohydrates also serve as a fermentation substrate for alcohol-producing yeasts; about 80% of such alcohol is ethanol. We studied the role of ethanol as an olfactory cue for detection of ripe fruits by the Egyptian fruit bat, Rousettus aegyptiacus. We also studied the role of ethanol as an appetitive stimulant in these bats. An odor preference experiment showed that bats significantly prefer mango juice to pure aqueous ethanol at low concentrations (i.e., 0.001%, 0.01%, 0.1 % and 1% ethanol v/v). Bats showed no preference for mango juice mixed with different levels of ethanol (0.001%, 0.01%, 0.1 % v/v) relative to mango juice alone. However, when mango juice was mixed with ethanol at high levels (1% and 2% v/v), bats significantly preferred the mango juice. Consumption of food containing low concentrations of ethanol (0.01%; 0.1%; 0.5%) did not differ significantly from a control, ethanol-free diet, whereas consumption of food with higher concentrations of ethanol (1% and 2 % v/v) decreased significantly. The relationship between food consumption and the concentration of dietary ethanol was best fit by an inverse quadratic regression, suggesting that food consumption is highest at intermediate ethanol concentrations. Supported by US-Israel BSF grant 2001038.