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Hanya G & Bernard H (2015) Different roles of seeds and young leaves in the diet of red leaf monkeys (Presbytis rubicunda): Comparisons of availability, nutritional properties and associated feeding behavior. International Journal of Primatology 36: 177-193.
Abstract
It is important to clarify the roles of different types of foods in the
diet of primates that switch to other foods as preferred food items become
rare. Using red leaf monkeys (Presbytis rubicunda) in Danum Valley, Borneo, as an example, we compare the availability and
nutritional properties of young leaves and seeds, as well as the monkeys'
feeding behavior, to examine food choice and how such choices may affect
their competitive regime. Over 21 months, the number of flushing trees
was larger than that of fruiting trees. When we compared nutritional content
for all species, including those that the monkeys did not eat, seeds contained
more lipids than young leaves but young leaves did not have any nutritional
advantage over seeds. However, when we compared only food species, young
leaves contained more crude ash than seeds. The proportion of food species
to the total available species was significantly higher for seeds than
for young leaves. In addition, red leaf monkeys selected young leaf species
with higher digestible protein, but no nutritional component predicted
seed selection. Young leaves are nutritionally low-quality in general,
so monkeys may need to select species with higher-quality leaves. However,
seeds generally have high-quality nutritional values, so it may not be
necessary to select species with marginally higher quality. When eating
seeds, the number of animals eating in the patch was larger, and this feeding
in the patch tended to last longer than when eating young leaves, suggesting
more intense feeding competition when feeding on seeds. In conclusion,
seeds and young leaves have different nutritional advantages as a food
and red leaf monkeys were more selective when eating young leaves than
when eating seeds.
Key words: colobus
monkeys, dietary switch, fallback foods, food selection, preferred foods
<Written by: Goro Hanya (hanya.goro.5z<atmark>kyoto-u.ac.jp)>
<Contact: Goro Hanya (hanya.goro.5z<atmark>kyoto-u.ac.jp)>
<Last update: March 2, 2015>