Fruits and nectars vary in their sugar composition according to the kind of animals that ingest them. It has been hypothesized that the preferences and physiological characteristics of animals have influenced the evolution of sugar composition of plant products associated with certain groups of seed dispersers and pollinators. I review studies conducted on bats to test the generality of this hypothesis, in particular in the neotropics. The hypothesis is not supported for plants consumed by New World bats. Some alternatives to explain evolution of sugar composition in bat flowers and fruits in the neotropics are discussed. © Museum and Institute of Zoology PAS.