Gustatory responses in primates to the sweetener aspartame and their phylogenetic implications

Two-bottle preference tests have been applied to 70 (sub-) species of the order of Primates and, for comparison, to the tree shrew (Tupaia belangeri) to determine their responses to aspartame (APM), the first known sweet-tasting dipeptide which has to man a sweetness potency of about 200 times that of sucrose. It was found that only the Cercopithecidae, the Hylobatidae and the Pongidae respond like man to this dipeptide and prefer it to water. The other primates tested to date, show no response to this sweetener. From a phylogenetic point of view, we note that APM shows species specificity similar to thaumatin. Thus, a clear dichotomy exists within the order of Primates with respect to both thaumatin and APM. The results here illustrate once more the gustatory diversity among primates and are a compelling argument for the existence of different sweet taste receptors or recognition sites in primate specie