Abstract:
Invertebrates are the main source of protein for many small-to-medium sized monkeys. Prey vary in size, mobility,
degree of protective covering, and use of the forest, i.e. canopy height, and whether they are exposed or embed themselves in
substrates. Sex-differentiation in foraging patterns is well documented for some monkey species and recent studies find that color
vision phenotype can also affect invertebrate foraging. Since vision phenotype is polymorphic and sex-linked in most New World
monkeys - males have dichromatic vision and females have either dichromatic or trichromatic vision - this raises the possibility
that sex differences are linked to visual ecology. We tested predicted sex differences for invertebrate foraging in white-faced
capuchins Cebus capucinus and conducted 12 months of study on four free-ranging groups between January 2007 and September
2008. We found both sex and color vision effects. Sex: Males spent more time foraging for invertebrates on the ground. Females
spent more time consuming embedded, colonial invertebrates, ate relatively more “soft” sedentary invertebrates, and devoted
more of their activity budget to invertebrate foraging. Color Vision: Dichromatic monkeys had a higher capture efficiency of exposed
invertebrates and spent less time visually foraging. Trichromats ate relatively more “hard” sedentary invertebrates. We conclude
that some variation in invertebrate foraging reflects differences between the sexes that may be due to disparities in size,
strength, reproductive demands or niche preferences. However, other intraspecific variation in invertebrate foraging that might be
mistakenly attributed to sex differences actually reflects differences in color vision [Current Zoology 56 (3): 300–312, 2010].
