Showing papers by "Anthony Di Fiore published in 2013"

Hyperdominance in the Amazonian Tree Flora

Abstract: The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species—less diverse than the North American tree flora—accounts for half of the world’s most diverse tree community.

Effects of predation risk on the grouping patterns of white-bellied spider monkeys (Ateles belzebuth belzebuth) in Western Amazonia

Abstract: Predation is proposed to be one of the most important factors influencing the evolution of mammalian societies. Although predation risk is thought to influence both the behavior and grouping patterns of most diurnal primates, evidence supporting this hypothesis is still limited. The spatial and temporal patterns of mineral lick use by one group of white-bellied spider monkeys (Ateles belzebuth) were evaluated, based on the growing evidence that mineral licks are perceived as areas of relative high predation risk by Neotropical primates. The area immediately surrounding the mineral lick was the most intensively used area within the home range of the study group, particularly by large subgroups of monkeys, and there were differences in mean subgroup size on days of mineral lick visitation versus days without lick visits. Additionally, on days of mineral lick visitation, subgroup size reached its maximum specifically during the period of lick visitation. Finally, on visit days subgroups showed a greater increase in size and higher fusion rates in the 2 hr before arriving at the lick in comparison with matched time windows on non-visit days. Together, these results provide an example of how primates employ behavioral strategies that might reduce the effects of predation. This study also demonstrates how taxa characterized by a high degree of fission-fusion dynamics can allow us to test hypotheses regarding the effects of socioecological variables on primate grouping patterns. Am J Phys Anthropol 150:579–590, 2013. © 2013 Wiley Periodicals, Inc.

Evolutionary Biology and Conservation of Titis, Sakis and Uacaris: Pair-mate relationships and parenting in equatorial saki monkeys ( Pithecia aequatorialis ) and red titi monkeys ( Callicebus discolor ) of Ecuador

Abstract: Socially-monogamous primates are often described as displaying a suite of behavioral characteristics that includes a prolonged and essentially exclusive mating relationship between mates, joint participation of mates in territory defense, and extensive male involvement in offspring care. Amongst the pitheciins, titi monkeys (Callicebus spp.), and saki monkeys (Pithecia spp.) frequently live in sociallymonogamous groups. We present here comparative data collected over four years on the social interactions of Neotropical adult male and female titi monkeys (Callicebus discolor, n = 2 groups) and saki monkeys (Pithecia aequatorialis, n = 1 group comprising 2 different male-female pairs) in the Yasuní National Park and Biosphere Reserve in Ecuador. Our data suggest that these two pitheciins do not both fit the mold of “classic” social monogamy. Despite their similar grouping patterns, the two species differ markedly in the quality of the social relationships between pairmates. Saki pairmates are less affiliative and engage less in behaviors thought to be instrumental to the development and maintenance of pair bonds (e.g., grooming, coordinated vocal displays) than titi pairmates. There are also dramatic differences in the extent to which males invest directly in offspring. While titi males invest heavily in infants, saki males provide little direct paternal care. Male sakis may be providing indirect investment, but they certainly do not seem to mitigate the energetic costs of infant care for their partners to the same extent as titi males do. Thus, male sakis apparently remain in sociallymonogamous relationships for reasons disassociated from paternal care. Our results suggest that different ecological and/or social factors may underlie the expression of social monogamy in these two pitheciins. INTRODUCTION Socially-monogamous primates are often described as displaying a suite of behavioral characteristics that includes a high degree of affiliation and social tolerance among pairmates (Kleiman 1977; Fuentes 2002; Reichard 2003). Traditional conceptions of pair bonding also imply that the affiliation is mutual, with both individuals being responsible for maintaining their close spatial association (Anzenberger 1988; Palombit 1996; Fernandez-Duque et al. 2000). Among the pitheciins, titis (Callicebus spp.), conform to this “classic” pattern of social monogamy. They are always encountered in small groups of two to five individuals, the nucleus of which is an adult male and an adult female (Kinzey 1981; Wright 1985; Robinson et al. 1987; Defler 2004; Carrillo et al. 2007; Norconk 2007). In wild groups, pairmates typically stay within a few meters of each other during feeding, traveling and resting periods, and show coordinated activities (Mason 1966; Robinson 1979; Robinson 1981; Kinzey and Wright 1982; Wright 1985; Mendoza and Mason 1986; Price and Piedade 2001). Based on the high degree of intimacy, coordination, and interdependence between pairmates, the existence of a strong and specific mutual attachment or “bond” is regularly inferred (Mason 1975; Anzenberger 1988; FernandezDuque et al. 1997). The existence of a pairbond has been unequivocally demonstrated in captivity, where pairmates show clear behavioral and physiological signs of distress following separation (Mendoza and Mason 1986). Our understanding of pairmate relationships in sakis (Pithecia spp.) is far less clear than in titis. Sakis have also been reported to live in small social groups that include a single breeding pair and up to several young. Although there have also been studies reporting larger groups (Norconk 2007), most of those groups were found in island habitats that limit the dispersal possibilities of individuals (Setz and Gaspar 1997; Vié et al. 2001; Norconk 2006), or during censuses of non-habituated individuals that limit the possibility of precise group identification (Lehman et al. 2001). Thus, there is little demographic evidence suggesting routine deviation from social monogamy in Pithecia. Additionally, our knowledge of saki social behavior is likewise limited, since there have only been a handful of studies focused on identified and habituated individuals (Setz and Gaspar 1997; Norconk 2006; Di Fiore et al. 2007). Coordinated displays and joint participation in territory defense are also thought to reflect the existence of a pair bond between the male and the female of a socially monogamous group (Robinson 1979; Robinson 1981; Mitani 1984; Raemaekers and Raemaekers 1985). Titis use ranges with relatively little overlap, and routinely perform behaviors at the borders of those ranges that include duetting and joint visual displays (Mason 1968; Robinson 1981; Wright 1985; Price and Piedade 2001). The two adults perform these behaviors in a highly coordinated fashion, sitting or standing side-by-side while calling or displaying. For sakis, on the other hand, the specific contributions of male and female pairmates to inter-group interactions or territory defense remain unexamined. The limited data available on use of space by sakis in non-island habitats indicate that their ranges may be somewhat exclusive and defended (Vié et al. 2001; Norconk et al. 2003). Preliminary playback experiments in Pithecia aequatorialis suggest that the male may respond more to a potential intruder than the female (Di Fiore & Fernandez-Duque, unpublished data, 2006). Finally, extensive male involvement in infant care is also commonly associated with social monogamy (Kleiman 1981; Kleiman and Malcolm 1981; Palombit 1999; Maestripieri 2002). Among the pitheciins, the involvement of the titi male in infant care is one of the most unique aspects of the social organization of the genus (Wright 1984; Mendoza and Mason 1986; Hoffman et al. 1995; Norconk 2007). The male carries the infant most of the time and also plays, grooms, and shares food with the infant. Although studies of infant care in free-ranging habituated groups have been somewhat limited (Kinzey and Becker 1983; Wright 1984; Tirado-Herrera and Heymann 2000; TiradoHerrera and Heymann 2004), there have been several detailed studies of parental behavior and infant development in captive groups (Fragaszy et al. 1982; Mendoza and Mason 1986; Hoffman et al. 1995). These studies suggest that, in titis, the infant may be primarily attached to the putative father rather than the mother (Mendoza and Mason 1986; Hoffman et al. 1995). In all of the other pitheciin genera, by contrast, direct paternal care is relatively absent. Male sakis do not routinely transport infants, although they may play and interact socially with older young (Norconk 2007). The extent to which strong pair bonds characterize sakis like they do in titis has not been investigated. Nor have there been evaluations of paternal care in sakis that consider the services that males may provide to females and their offspring, such as antipredator vigilance or territory defense. In the following paragraphs, we give a descriptive overview of the patterns of pairmate relationships and paternal care seen in Equatorial saki monkeys (P. aequatorialis) and red titi monkeys (Callicebus discolor), based on comparative data collected from two groups of titis and one group of sakis in western Amazonia. METHODS Area of study Since 2003, we have been studying three species of monogamous primates (owl monkeys: Aotus vociferans; titi monkeys: Callicebus discolor; saki monkeys: Pithecia aequatorialis) at the Tiputini Biodiversity Station (76° 08’ W, 0° 38’ S), located in the Yasuní National Park and Biosphere Reserve in Ecuador (Carrillo et al. 2007; Di Fiore et al. 2007; Fernandez-Duque et al. in press). The study site, on the left bank of the Río Tiputini, covers approximately 650 hectares of primary tropical rainforest that can be accessed by an extensive trail system (Figure 1). Rainfall in the region typically totals more than 3000 mm per year (Di Fiore and Rodman 2001). INSERT FIGURE 1 ABOUT HERE Groups of Study The saki group has been monitored continuously since November 2003. During that month, we darted and captured the adult male and fitted him with a radio collar following procedures we have also used to capture owl monkeys (Aotus azarai) in Argentina (Fernandez-Duque and Rotundo 2003), as well as owl monkeys (Aotus vociferans), titi monkeys (Callicebus discolor), capuchins (Cebus albifrons), squirrel monkeys (Saimiri), spider monkeys (Ateles belzebuth), and woolly monkeys (Lagothrix lagotricha) in Ecuador (Di Fiore & Fernandez-Duque, unpublished data, 2007). At the time of darting, the group consisted of an adult male, an adult female, and a male juvenile of approximately six months of age. The original adult male was replaced by a new adult male in October 2004 (Di Fiore et al. 2007); the dependent juvenile dispersed in October 2007, when he was approximately 4.5 years of age; and two infants were born to the adult female in March 2005 and November 2006. The first infant disappeared in February 2006 when it was approximately 11 months old and the second one is in the group as of December 2007. Regarding the titis, we report data collected from one fully-habituated group studied since November 2003 and a second group added to the study in October 2006. The first group consisted initially of two animals, an adult male and an adult female. During these years, the female gave birth to two offspring. The first one was born in January 2004 and disappeared in November 2006 when it was almost three years of age. The second one, born in January 2005, disappeared in February 2006 when it was 13 months old. The original adult female disappeared in March 2007, and she was replaced by a new adult female shortly thereafter. A new infant was born to the new female in December 2007. The second group consisted of an adult male-female pair when it was added to the study. Two infants were born in this group, one in November 2006 and the other in November 2007. Dat

Male philopatry in spider monkeys revisited

Abstract: Dispersal patterns are critical for understanding social systems as they influence social interactions and relationships. Spider monkeys (Ateles spp.) are typically described as being characterized by male philopatry and female dispersal, with these patterns reflected in stronger affiliative and cooperative relationships among males than among females. Recent findings, however, indicate that male–male relationships may not be as uniformly strong as previously thought, which suggests that male philopatry in spider monkeys may not be universal. Here, we report the first confirmed cases of male immigration and group takeover in spider monkeys. Data were collected on one community of Ateles geoffroyi in northwestern Costa Rica. Behavioral and demographic data were recorded during subgroup follows across 6.5 years, and fecal samples of community members were collected for genetic analysis of relatedness. We documented two separate cases of immigration involving multiple males, which resulted in take-over of the study community by extra-community males and the concomitant disappearance of the resident males. In the study community, males were no more closely related to one another, on average, than females were, contrary to what would be expected if males were the more philopatric sex. Comparison of corrected assignment indices for males and females also revealed no evidence of sex-biased dispersal. Our findings suggest that in spider monkeys male immigration may occur under certain demographic circumstances, contributing to a view of greater flexibility in their social system than previously appreciated. This discovery has implications for other species that are typically characterized by male philopatry. Am J Phys Anthropol 152:86–95, 2013. © 2013 Wiley Periodicals, Inc.

Loud calls as a mechanism of social coordination in a fission–fusion taxon, the white-bellied spider monkey (Ateles belzebuth)

Abstract: Spider monkeys (Ateles spp.) live in social groups that exhibit high levels of fission–fusion dynamics, in which group members form subgroups of varying sizes and compositions. Within these fluid societies, how individuals establish contact with dispersed group members with whom they might choose to associate remains unclear. Long-range vocalizations might facilitate interactions between group members and provide a means of social coordination in fission–fusion societies. We evaluated this possibility for one spider monkey vocalization, the loud call, by examining calling behavior, the relationship between loud calls and changes in subgroup size, and the response of individuals to distant calls and playback experiments in a single study group. We found that 82 % of loud calls were emitted within 30 min of a call from a different location, suggesting that individuals frequently emit loud calls in response to the calls of distant group members. Subgroups that emitted loud calls, especially those that responded to distant calls, were much more likely to experience an increase in subgroup size within an hour after calling than those that did not. Animals also approached distant loud calls more than they avoided or ignored these calls. Finally, playbacks of male calls demonstrated that females respond preferentially to the calls of some individuals over others. Taken together, these results provide support for the hypothesis that spider monkey loud calls function to facilitate and initiate interactions between dispersed group members and suggest that vocal signals can play an important role in influencing social interactions in fission–fusion societies.