Taste preferences of the common vampire bat (Desmodus rotundus)

Abstract

Taste preference tests, with simultaneous presentation of treated and untreated food, were administered to 24 common vampire bats (Desmodus rotundus). The bats received brief exposures to four different stimuli representing sweet, salty, sour, and bitter tastes, each at four different concentrations. Despite a strong location bias, the bats significantly (P < 0.01) avoided the highest concentrations of the salty, sour, and bitter tastes. Consumption of the sweet stimulus at all concentrations was similar to that of the untreated standard. Vampires evidently can discriminate based on taste, although their ability is apparently poorly developed when compared with some euryphagous species such as the rat. Hence, taste is probably not a factor in host selection by the vampire.

Vampire bats exhibit evolutionary reduction of bitter taste receptor genes common to other bats

“…Behavioural tests have demonstrated that vampire bats possess poorly developed taste ability because they showed indifference to sweet and detected bitter, sour and salty tastants in high concentrations [11], and they even lost taste-aversion learning for poison avoidance [33]. Our genetic data are fully consistent with the behavioural tests.…”

“…Second, many pseudogenized T2Rs in vampire bats suggest that their bitter taste is greatly reduced and the reduction of bitter taste was also observed behaviourally in Desmodus rotundus [11]. Third, the evolutionary conservation of several T2Rs and taste signaling pathway strongly support the behavioural finding in which vampire bats still retain some bitter taste ability, evidenced by the detection of bitter tastants in relatively higher concentrations [11]. Consistent with the genetic data supporting the view of retaining some bitter taste in vampire bats, anatomical studies discovered normal taste buds in the canonical taste structures [35] and electrophysiological recordings identified functional taste receptors in these bats [36].…”

“…In addition, we found the T1R3 to have a common 26 bp deletion in Desmodus rotundus [10] and Diphylla ecaudata, which would shift the ORF and result in loss of most transmembrane domains of the receptor in their common ancestor (electronic supplementary material, figure S4). Because T1R3 encodes the shared subunit of sweet and umami taste receptors [34], this finding strongly suggests that both sweet and umami tastes were lost in the common ancestor of vampire bats approximately 26 Ma [9], although the umami taste sensitivity has not been examined behaviourally [11]. Second, many pseudogenized T2Rs in vampire bats suggest that their bitter taste is greatly reduced and the reduction of bitter taste was also observed behaviourally in Desmodus rotundus [11].…”

“…Because T1R3 encodes the shared subunit of sweet and umami taste receptors [34], this finding strongly suggests that both sweet and umami tastes were lost in the common ancestor of vampire bats approximately 26 Ma [9], although the umami taste sensitivity has not been examined behaviourally [11]. Second, many pseudogenized T2Rs in vampire bats suggest that their bitter taste is greatly reduced and the reduction of bitter taste was also observed behaviourally in Desmodus rotundus [11]. Third, the evolutionary conservation of several T2Rs and taste signaling pathway strongly support the behavioural finding in which vampire bats still retain some bitter taste ability, evidenced by the detection of bitter tastants in relatively higher concentrations [11].…”

Major taste loss in carnivorous mammals

“…Tas1r2 also is known to be pseudogenized in chicken, tongueless Western clawed frogs, and vampire bats (11,15). The loss of the sweet taste receptor in chicken and vampire bats is consistent with their sweet insensitive behavior (16,17). It is yet to be established how Western clawed frogs respond to sweeteners.…”