Background
Aims
The sense of taste is important for food selection, as different taste sensations provide information regarding how suitable any given food item is for consumption.
Differences in taste perception between species is thought to reflect evolutionary adaptations to dietary specializations.
As fruits contain a variety of sweet and sour tastants, a high sensitivity to sweet and sour tastants should be adaptive for frugivorous primates to effectively select the most appropriate fruits.
Out of the five taste qualities, sour taste is often associated with the degree of ripeness of a fruit, where a ripe fruit is less sour than an unripe fruit. Additionally, fruits contain a variety of acidic tastants:
- Citric acid & Malic acid – Most common acids found in fruit, store respiratory energy
- Ascorbic acid (vitamin C) – Vital for physiological processes in many mammals, particularly important for primates as they cannot synthesise their own requirements for vitamin C and must acquire this through their diet
- Acetic acid – Byproduct of fermentation, may indicate overripeness
- Tannic acid – Found in the skin and husks of fruits and primarily serve as a plant defense mechanism
White-faced sakis are neotropical frugivorous primates, who include a large proportion of unripe fruits and seeds in their diet. Additionally, they are often considered a seed predator.
- Most frugivorous primates are considered seed dispersers, and they simply discard the seeds of the fruits they eat
- Seed predators exploit the seeds of fruit (i.e. eat them), either by eating just the seed or by consuming the fruit whole
The consumption of unripe fruits and seeds makes the white-faced saki an interesting species to study in terms of sour-taste responsiveness!
Due to the lack of data on taste responsiveness to sour tastants in primates, it was therefore the aim of the present study:
- To determine the taste responsiveness of four white-faced sakis to the five food-associated acids citric acid, ascorbic acid, malic acid, tannic acid, and acetic acid.
- To determine the sour-taste tolerance of the four white-faced sakis to varying concentrations of citric acid in a sucrose mixture compared to a 50 mM sucrose solution.
- To compare the obtained results on taste preference thresholds and sour-taste tolerance with existing data from different primate species, to further assess the importance of sour-taste perception and the behavioral relevance of sour-taste for food selection.
Want to know more? Head on over to the Materials & Methods!
