Inability of bats to synthesise L-ascorbic acid

Abstract

RECENT speculations on the loss and retention of the ability to synthesise L-ascorbic acid (vitamin C) during evolution of animals have been based on few data, often for limited numbers of species¹. Published reports for the Mammalia deal mostly with domesticated and laboratory species, and there is little information on ascorbate biosynthesis in wild populations. The status of knowledge on bats typifies this paucity of data. It has been reported that two species of bats (of approximately 850 species), like anthropoid primates and guinea pigs, are unable to synthesise vitamin C because they lack L-gulonolactone oxidase². When present, this enzyme catalyses the final step in the biosynthesis of L-ascorbic acid from glucose. These species are Pteropus medius³ (=P. giganteus), a fructivore of the suborder Megachiroptera, and Vesperugo abramus^2,4 (presumably Pipistrellus coromandrd), an insectivore of the only other chiropteran suborder, the Microchiroptera. We have assayed livers of 34 species of New World microchiropteran bats for L-gulonolactone oxidase (Table 1). These species represent six families, temperate and tropical environments, and a wide variety of food habits and life histories. Within the limits of our assay, we could not detect L-gulonolactone oxidase in livers of any of the species examined. This greatly strengthens the hypothesis that all members of the Chiroptera lack the ability to synthesise vitamin C, which is surprising considering the diversity of bats and their many highly specialised diets.