The eight monkey species occurring in Surinam were studied in the Raleigh-vallen-Voltzberg Nature Reserve along the Coppename River. Special emphasis was placed on determining how these eight species divide up available habitat and food resources within a 300-ha study area. Cebus apella apella is probably the most adaptable of the Surinam monkeys. It was found mainly in the understory and lower to middle parts of the canopy of all five forest types (high rain forest, low rain forest, mountain savanna forest, liane forest, pina swamp forest) in the study area, and entered a variety of edge habitats. Saguinus midas midas, the only callitrichid in Surinam, also occurred mainly in the understory and lower to middle parts of the canopy of all five forest types, but was the only species to spend more time in edges than in non-edge habitats. Alouatta seniculus was most often seen in the middle to upper strata of high forest, but occasionally entered the four other forest types and a variety of edges. Cebus nigrivittatus is apparently less adaptable than its congener and was largely restricted to the understory and lower to middle strata of high forest. It occasionally entered two other forest types as well, but was rarely seen in edges. Chiropotes and Pithecia were both found almost exclusively in high forest and mountain savanna forest, but Chiropotes was mainly in the upper part of the canopy and in emergents, whereas Pithecia occupied the lower to middle parts of the canopy and the understory. Neither species made much use of edges. Ateles paniscus paniscus and Saimiri sciureus represent the extremes of primate adaptation in the Voltzberg area. Ateles was the most restricted species, and was found almost exclusively in high forest. It very rarely entered edges and was most often seen in the uppermost forest strata. In contrast, Saimiri was the only species that was not found most often in high forest, and it occurred consistently lower than any other monkey in the area. More than 50% of all Saimiri observations were in liane forest, a habitat rarely or never entered by most of the other species, and more than 60% were in the understory stratum. Saguinus, Saimiri, Cebus apella and C. nigrivittatus were omnivorous, with Saimiri apparently eating the most arthropods. The four remaining species were not seen feeding on insects or other animals. All eight species included a high proportion of fruit in their diet, with flowers and sometimes leaves usually playing a minor role. The two largest species, Alouatta and Ateles, were the most folivorous, but Alouatta was the only one that ate mature leaves and its leaf intake far exceeded that of Ateles. The three smallest species (Saguinus, Saimiri, Pithecia) did not eat leaves at all. Chiropotes was an important seed predator; Pithecia and C. nigrivittatus may also depend heavily on seeds. Alouatta and Saimiri were never seen acting as seed predators. Alouatta and Ateles were major seed dispersers. The other six species occasionally dispersed seeds, but to a much lesser extent.

(back cover) HABITAT PREFERENCES, DIET, FEEDING BEHAVIOR AND SOCIAL ORGANIZATION OF THE BLACK SPIDER MON KEY, ATELES PANISCUS PANISCUS, IN SURINAM.A Socioecological Field Study.This monograph reports on a 26 month socioecological study of black spider monkeys (Ateies paniscus paniscus) in the Raleighvallen -Voltzberg Nature Reserve, Surinam. It recognizes the .fun damental importance of food to the behavior and the regulation of population density fox this primate. It clarifies the complex tempo ral and spatial effects of tropical rain forest food sources on the be havior of a group of spider monkeys, concentrating on food category, food plant identity and phenology, and quantity, density and dis persion of the most important food sources. In addition, the present study describes habitat choice, optimal feeding strategy and sexual behavior of the spider monkey, and discusses implications of diet for social behavior. This study is also fundamental to conservation. Specialized in eating mature fruits, the spider monkey is a very im portant dispersal agent for many trees and lianes, particularly ca nopy species. However, the spider monkey is probably the most vulnerable monkey species in Surinam and it is disappearing ra pidly throughout the remainder of its range. Unfortunately, it is lar ge and noisy and can be easily tracked and hunted. It is largely restricted to undisturbed high forest, and consequently habitat des truction has more effect on it than on most other species. Together with its slow reproductive rate (a female gives birth only once every four or five years), this means that the species is poorly adapted to recover from exploitation. In order to implement proper measu res for conservation, data on forest type preferences, diet and so cial behavior of the species, or on closely related species, in undisturbed areas, such as the one described in this monograph, are essential tools for assessing the potential of proposed protected areas.

New York at Stony Brook, Stony BrookData on the diet of Chiropotes satanas chiropotes, the northern bearded saki, has been collected during several years of primate field observations in the Raleighvallen-Voltzberg Reserve in Suriname. This species feeds predominantly on immature seeds and ripe fruit, mainly the former. Chiropotes is especially fond of the members of the Brazil nut family, Lecythidaceae, and other species with exceptionally hard or tough seed pods. Concomitantly, Chiropotes shows striking dental and gnathic adaptations that facilitate opening and ingesting these well-protected food items. Seed predation in the Old World colobine, Colobus satanas, has been discussed primarily as a strategy for survival in forests characterized by leaves with low nutrient content and high toxicity; however, it now appears that arboreal seed predation is a relatively widespread primate dietary strategy found among higher primate species in a variety of forest types on three continents. It is yet another way of "making a living" in a tropical rain forest.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org..Wiley-Blackwell and Nordic Society Oikos are collaborating with JSTOR to digitize, preserve and extend access to Oikos. . M. 1996. Avian dispersal of "mimetic seeds" of Ormosia lignivalvis by terrestrial granivores: deception or mutualism? -Oikos 75: 249-258.Several tropical forest legume species producing hard and brightly-colored seeds, which apparently evolved as mimics of fleshy fruit and arillate-seed models, have been presumed to be dispersed by avian frugivores through non-mutualistic interactions involving sensorial deception. Here we examine the interactions between a typical so-called "mimetic seed" species and its potential dispersers in an Amazonian forest site, and propose that such interactions are best interpreted as mutualistic. Ormosia lignivalvis (Leguminosae: Papilionaceae) is a relatively rare but widespread canopy tree producing naked seeds with a conspicuous, bicolored (scarlet and black) hard seed coat, containing no nutrient rewards to its putative dispersers. Mature seeds are gradually released from dehiscent pods in a piecemeal fashion, during an extended fruiting period of up to 8 months, but may be retained by persistent funicles throughout the year. Intact Ormosia seeds were found in stomach contents of large-bodied terrestrial birds -including one tinamou, one trumpeter, and two cracid species -which appear to be the main dispersers. On the other hand, a total of 185 h of vigils of 5 fruiting tree crowns failed to result in any observed cases of seed removal by arboreal frugivores. Laboratory measurements of seed resistance, elasticity, and hardness showed that Ormosia seeds are extremely hard, and could, therefore, aid in the mechanical breakdown of softer seeds which make up a large proportion of the diet of these terrestrial granivores. We argue that the hard, non-elastic 0. lignivalvis seeds, and perhaps a number of other so-called mimetic-seed species, can function as similarly shaped and sized mineral grit universally swallowed by large gallinaceous birds, in that they help to crush and grind the mostly pliable seeds digested by their dispersers. This interaction is thus best described as a mutualism in that (1) Ormosia germination is greatly enhanced by the abrasive gut treatment of avian granivores, and (2) such birds would otherwise find no adequate gizzard grit substitutes in environments conspicuously lacking small pebbles, such as the lowland rainforests of sedimentary river basins of Amazonia.

ABSTRACT. Insects of at least six orders were found in the stomachs of four wild-shot Chiropotes satanas chiropotes from Surinam, thus providing further evidence of omnivory in this genus of Neotropical primates.