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Heymann E.W.,Abteilung Verhaltensokologie and Soziobiologie
Ecotropica | Year: 2011

Due to their principally arboreal way of life, primates can potentially interact with flowers from a broad diversity of tropical and subtropical plants. In fact the consumption of flowers and/or nectar has been reported for many primate species, but the role in primate diets is generally underestimated. Also, evidence has been provided for the role of some primate species as pollinators. This paper aims at reviewing information on the interactions between primates and flowers and to examine factors like body mass and dietary strategy as determinants for the type of interaction, i.e. whether entire flowers or nectar are consumed. I also review the available evidence for pollination by primates and the consequences of flower predation for subsequent fruit set. I conclude that (a) the contribution of flowers and/or nectar to primate diets can be substantial, at least seasonally, and therefore (b) primate-flower interactions (flower predation, pollination) are more prevalent and may have larger impact on affected plants than previously thought.

Aquino R.,National Major San Marcos University | Cornejo F.M.,National Major San Marcos University | Heymann E.W.,Abteilung Verhaltensokologie and Soziobiologie
Primates | Year: 2013

We report information on population density, group size, and habitat preferences of primates along the lower Río Urubamba and in the Río Urubamba-Río Tambo interfluvium, in central-eastern Peruvian Amazonia, an area that has been little explored with regard to its primate fauna. During 425 km of transect walks in October-November 2008 and April-May 2009 totally 174 groups of nine primate species were encountered, the most common being Callicebus brunneus (45 groups), Saguinus imperator (41 groups), and Aotus nigriceps (26 groups). Group sizes were smallest for A. nigriceps and C. brunneus (mean of 2.8 and 2.9, respectively) and largest for Saimiri boliviensis (mean 15.6). Population densities were lowest for Lagothrix cana (3.3 individuals/km2) and highest for A. nigriceps (31.1 individuals/km2). Groups of C. brunneus, S. imperator, S. boliviensis, Cebus albifrons, and Cebus apella were most frequently (83 % of sightings) encountered in semi-dense or in open primary forest that included stands of bamboo (Guadua sarcocarpa) or where bamboo was a very common species. © 2013 The Author(s).

Culot L.,Sao Paulo State University | Culot L.,University of Liege | Huynen M.-C.,University of Liege | Heymann E.W.,Abteilung Verhaltensokologie and Soziobiologie
Methods in Ecology and Evolution | Year: 2015

Summary: Seed dispersal effectiveness (SDE) is a conceptual framework that aims at quantifying the contribution of seed dispersal vectors to plant fitness. While it is well recognized that diplochorous dispersal systems, characterized by two successive dispersal steps performed by two different vectors (Phase I = primary seed dispersal and Phase II = secondary seed dispersal) which are common in temperate and tropical regions, little attention has been given to distinguishing the relative contribution of one-phase and two-phase dispersal to overall SDE. This conceptual gap probably results from the lack of a clear methodology to include Phase II dispersal into the calculation of SDE and to quantify its relative contribution. We propose a method to evaluate the relative contribution of one-phase and two-phase dispersal to SDE and determine whether two seed dispersers are better than one. To do so, we used the SDE landscape and an extension of the SDE landscape, the Phase II effect landscape, which measures the direction and magnitude of the Phase II dispersal effect on overall SDE. We used simulated and empirical data from a diplochorous dispersal system in the Peruvian Amazon to illustrate this new approach. Our approach provides the relative contribution of one-phase SDE (SDE1) and two-phase SDE (SDE2) to overall SDE and quantifies how much SDE changes with the addition of Phase II dispersal. Considering that the seed dispersal process is context dependent so that Phase II depends on Phase I, we predict the possible range of variation of SDE according to the variation of the probability of Phase II dispersal. In our specific study system composed of two primate species as primary dispersal vectors and different species of dung beetles as secondary dispersal vectors, the relative contribution of SDE1 and SDE2 to overall SDE varied between plant species. We discuss the context dependency of the Phase II dispersal and the potential applications of our approach. This extension to the conceptual framework of SDE enables quantitative evaluation of the effect of Phase II dispersal on plant fitness and can be easily adapted to other biotic and/or abiotic diplochorous dispersal systems. © 2014 British Ecological Society.

Heymann E.W.,Abteilung Verhaltensokologie and Soziobiologie | Aquino R.,National Major San Marcos University
International Journal of Primatology | Year: 2010

In the literature, particularly in primatological books, the Peruvian red uakari (Cacajao calvus ucayalii) is generally considered as a species that is specialized on living in flooded forest, despite existing evidence to the contrary. Here we review all available information on habitats where Cacajao calvus ucayalii have been observed. Most sightings are from terra firme, including palm swamps, or from mixed habitats, including terra firme and flooded forest. Therefore, we conclude that the species is not a flooded-forest specialist, but is flexible in its habitat requirements and generally uses terra firme forests or a mixture of habitats. Proper recognition of habitat requirements is important for understanding the ecoethological adaptations of a species and for appropriate conservation measures. © 2010 The Author(s).

Alvarez S.J.,Abteilung Verhaltensokologie and Soziobiologie | Alvarez S.J.,University of Gottingen | Heymann E.W.,Abteilung Verhaltensokologie and Soziobiologie
American Journal of Physical Anthropology | Year: 2012

Callicebus and the pitheciins are closely related; however, differences in their diets and dental morphology suggest that they differ in the use of mechanically protected food. We describe physical traits of fruits consumed by white-handed titi monkeys (Callicebus lugens) and determine their influence on fruit part selection and immediate seed fate after fruit handling. We tested two hypotheses about the effects of mechanical fruit traits on fruit part selection and seed fate: (1) fruits selected for seed consumption are harder than fruits selected for their fleshy parts and (2) consumed seeds are softer than seeds with other fates. In addition, we analyzed the influence of other physical fruit traits on fruit part selection and seed fate. C. lugens included 69 species in its diet, from which it mainly consumed their fleshy parts. It also consumed seeds, alone or with fleshy fruit parts, but most of them ended up close to parent trees after being dropped or spat out. The first hypothesis was supported while the second was rejected, indicating that C. lugens tends to rely on hard fruits for obtaining seeds, while seed hardness had no influence on fruit part selection and seed fate, contrasting with the pattern reported for Pithecia and Chiropotes in other studies. Ripeness was the most influential factor for fruit part and seed fate discrimination. Results suggest a tendency to sclerocarpic foraging in C. lugens when feeding on seeds. Am J Phys Anthropol 2012. © 2012 Wiley Periodicals, Inc.

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