Physical Properties of Fruit and Seeds Ingested by Primate Seed Predators with Emphasis on Sakis and Bearded Sakis

Abstract

Several primate radiations exhibit dental adaptations that enable them to gain access to seeds embedded in well-protected fruit. To a database drawn from published sources in which hardness of fruit and seeds were tested in the field, we added an additional 100þ species of plants used as resources by pitheciin primates (specifically, South American white-faced sakis (Pithecia pithecia) and bearded sakis (Chiropotes spp.). This sample allowed us to compare hardness of fruit and seeds and deduce the relative incisive and masticatory capability of several primate taxa (New World monkeys, Old World monkeys, prosimians and chimpanzees). Pitheciins have very well developed and highly modified anterior dentition that they use in gaining access to mechanically-protected fruit. In addition, their molars bear thin, but decussated enamel that protects the tooth enamel from crack proliferation. The ability of sakis (Chiropotes spp. and Pithecia pithecia) to open fruit orally was comparable to larger-bodied Old World seed predators-Lophocebus and Cercocebus. But, baboons and chimpanzees masticate seeds that are two to three orders of magnitude harder than sakis or mangabeys. In spite of their puncture abilities, $40% of foods ingested by pitheciins were in the range of a ripe fruit eater (Ateles paniscus). This raises the possibility that pitheciins exemplify Liem's paradox, that is, ''that phenotypic specialization [is] not accompanied by ecological specialization'' (Robinson and Wilson, 1998:224). Last, we examined the possibility that seeds may serve as fallback resources for primate seed predators. While pericarp hardness may vary seasonally for some seed predators (e.g., mangabeys), our data on bearded sakis and white-faced sakis suggest that seeds are their primary resources year round and pericarp hardness is unrelated to seasonal variation in rainfall. Pitheciins evolved specialized dentition that affords them access to relatively abundant and highquality resources, a feeding strategy that results in minimal variation in resource availability seasonally. Anat Rec, 294:2092Rec, 294: -2111Rec, 294: , 2011. V V C 2011 Wiley Periodicals, Inc.

Beyond the Map: Enamel Distribution Characterized from 3D Dental Topography

“…A similar trend is observed in the saki ( Pithecia pithecia ), a notorious seed-eating New World monkey (Norconk and Veres, 2011). Pachymetric profiles of P. pithecia are thus characterized by a low slope at mean enamel thickness (Figure 5).…”

“…For instance, P. pithecia does not crack open the most challenging food it consumes with its molars, but with its strong and proclive incisors and canines (Kinzey and Norconk, 1993; Norconk and Veres, 2011). The seeds it crushes with its molars might therefore be tough, but they are significantly softer (Kinzey and Norconk, 1993).…”

“…While challenging foods are generally avoided by primates (Milton, 1979; Waterman et al, 1988; Hill and Lucas, 1996; Lucas et al, 2000), some species such as Pithecia, Pongo , or Cercocebus are durophagous and are thus expected to show dental adaptations to stress-limited food, including a relatively thicker enamel than non-durophagous species (Vogel et al, 2008; Norconk and Veres, 2011; McGraw et al, 2014). Indeed, a thick enamel lessens the deformation due to strain (Lucas et al, 2008).…”

Feeding Ecology of Northern Bearded Sakis (Chiropotes sagulatus) in Guyana

“…The high degree of seasonality of most tropical habitats requires primates to modify their diet and foraging behavior seasonally [Hemingway & Bynum, 2005]. During these periods, sympatric species may increase diet breadth (in terms of different types of resources consumed), increase dietary diversity (in terms of number of species consumed) and/or shift to less preferred fallback foods [Marshall & Wrangham, 2007;Norconk & Veres, 2011;Rosenberger, 1992]. While there may be extensive overlap in the diets of sympatric primates during periods of resource abundance, when resources become seasonally scarce, this overlap is reduced [Bowler & Bodmer, 2011;Rosenberger, 1992;Terborgh, 1986].…”

“…One group of primate specialists are those adapted to consuming seeds. Relatively high temporal and spatial availability of seeds may buffer seed predators against the detrimental effects of seasonal food shortages [Norconk & Veres, 2011;Norconk et al, 1998]. Seeds provide several advantages over other food items.…”