Leaf chemistry as a predictor of primate biomass and the mediating role of food selection: a case study in a folivorous lemur (Propithecus verreauxi).

Folivorous primate biomass has been shown to positively correlate with the average protein-to-fiber ratio in mature leaves of tropical forests. However, studies have failed to explain the mismatch between dietary selection and the role of the protein-to-fiber ratio on primate biomass; why do not folivores always favor mature leaves or leaves with the highest protein-to-fiber ratio? We examined the effect of leaf chemical characteristics and plant abundance (using transect censuses; 0.37 ha, 233 trees) on food choices and nutrient/toxin consumption in a folivorous lemur (Propithecus verreauxi) in a gallery forest in southern Madagascar.

Relationship between taste thresholds and hunger under debate.

We determined taste recognition thresholds for six compounds (sucrose, fructose, sodium chloride, quinine sulphate, PROP and liquorice) in fasting students and, in the same subjects, after a meal. The testing procedure was the staircase-method in blind conditions. Although taste sensitivity may vary with hormonal status, our results did not show any significant difference in taste recognition thresholds between hunger and satiety.