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There has been persistent decline in blue monkey (Cercopithecus mitis) population at Ngogo research site in the past 40 years for no clear reasons. In contrast, the populations of other nonhuman primates like the grey‐cheeked mangabeys (Lophocebus albigena) which share identical home ranges with blue monkeys have not been obviously affected. However, stakeholders attribute this decline to gastrointestinal parasitic diseases, hence the need to determine the profile of parasitic infections in blue monkeys and compare them to that of grey‐cheeked mangabeys within a shared home range. Faecal samples (n = 241) were subjected to diagnostic tests, namely sodium nitrate floatation and formol‐ether sedimentation before microscopic examination. 227 (94%) samples were parasite positive; six protozoa and 21 helminths were present. This implies that Ngogo hosts a high diversity of parasites which poses health risks to nonhuman primates. There was no significant statistical difference in the prevalence of the overall main pathogenic parasites between the two studied nonhuman primate species. Therefore, gastrointestinal parasites may not be the obvious cause of the proclaimed blue monkey population decline at Ngogo research site.

In primates, infanticide is occasionally observed during intergroup conflicts but does not fit the predictions of the sexual selection hypothesis. I report an observation of an intergroup infanticide during a sub-group foray in grey-cheeked mangabeys (Lophocebus albigena) at the Ngogo site in Kibale National Park, Uganda. Intergroup infanticide appears to be a form of extreme and long-term food defence across primate species, and occurs in conjunction with other forms of food defence.

Maternal styles have been intensively studied in a variety of terrestrial species of primates, but far less in arboreal species. However, to have a balanced view of the evolution of maternal care, it is necessary to investigate this behaviour in the context of habitat. Here, we investigate whether the mother’s parity, age and dominance rank, as well as the infant’s age and sex, influence maternal care and mother-infant proximity in arboreal grey-cheeked mangabeys (Lophocebus albigena). We observed 13 mother-infant dyads in four free-ranging groups for 6 months. Our main finding is that maternal care is a dynamic process affected by a mix of mothers’ and infants’ characteristics. We found that first-time mothers spent more time watching their infants than multiparous mothers, who carried, groomed and protected their infants more often. We also found that low-ranking mothers prevented their infants from leaving them more often than did high-ranking mothers. Moreover, mothers adjusted their care as infants became older. They groomed and protected female infants more than male infants, behaviours common in female-bonded species. Our study shows the ever-changing dynamics of maternal care related to infant age and highlights the role of the mother’s parity and rank in this process.

The pandemic outbreak and rapid worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is not only a threat for humans, but potentially also for many animals. Research has revealed that SARS-CoV-2 and other coronaviruses have been transmitted from animals to humans andvice versa, and across animal species, and hence, attracted public attention concerning host-virus interactions and transmission ways. Non-human primates (NHPs), as our evolutionary closest relatives, are susceptible to human viruses, and a number of pathogens are known to circulate between humans and NHPs. Here we generated global statistics of virus infection in NHPs (VI-NHPs). In total, 121 NHP species from 14 families have been reported to be infected by 139 DNA and RNA viruses from 23 virus families; 74.8 percent of viruses in NHPs have also been found in humans, indicative of the high potential for cross species transmission of these viruses. The top ten NHP species with high centrality in the NHP-virus network are two apes (Pan troglodytes, Pongo pygmaeus), seven Old World monkeys (Macaca mulatta, M. fascicularis, Papio cynocephalus, Lophocebus albigena, Chlorocebus aethiops, Cercopithecus ascanius, C. nictitans) and a lemur (Propithecus diadema). Besides apes, there is a high risk of virus circulation between humans and Old World monkeys, given the wide distribution of many Old World monkey species and their frequent contact with humans. We suggest epidemiological investigations in NHPs, specifically in Old World monkeys with close contact to humans, and other effective measures to prevent this potential circular transmission.

Evolutionary game theory posits that competitive ability affects the initiation of conflicts. When contests occur among groups, competitive ability is generally measured as the size of the group and larger groups are expected to win against smaller groups. However, in some cases, individual participation during intergroup conflicts appears unaffected by competitive ability. To test whether these instances might be due to an unduly strict definition of participation, I re-evaluate the responses of gray-cheeked mangabeys (Lophocebus albigena) to the calls of real and simulated neighboring groups. In contrast with previous analyses, I consider multiple measures of group size, treat movement responses as a continuous variable, and evaluate individual responses (N = 201 focal follows). Males made stronger approaches toward calling neighbors than females, though both sexes tended to retreat from groups that were

In tropical forest, there are many types of food for primates but their availability is not always predictable. We followed 6 species of primates in the wild in 3 countries, Uganda, Ghana, and Mexico, to see if the way they move through the forest change when the food items availability changes also. We found that behavior is flexible and primates modify the way they search for food according to the spatial and temporal distribution of food.

Long-distance vocalizations mediate spacing patterns by allowing groups to choose whether to draw close enough to a neighbor to initiate a short-range interaction. It is unclear, however, whether the patterning of calls and the resulting movements are invariant or change in response to social and ecological variables. In this study, we compare the impact of long-distance calls on neighboring groups' movements in two populations of grey-cheeked mangabeys (Lophocebus albigena) in Uganda, which differed widely in group density and food availability. We monitored movement responses of target groups to both naturally occurring and experimentally simulated "whoop-gobble" vocalizations of neighboring adult males to test whether responses indicated mate and food defense. When defending access to fertile females, males might coerce group members to move away from neighboring males; when defending fitness-limiting food resources, however, groups might approach and attempt to evict neighbors. Controlling for pre-call movement prior to the vocalization, we found no difference in group responses between the low- and high-density populations, and little support for either form of defense. Mangabey groups generally continued moving in their original direction, albeit at a slower pace, and deviations from this pattern were predictable: they avoided nearby callers but approached distant callers; they approached if the caller was in the area where home ranges overlapped; and approached when their own group contained multiple peak-estrous females. The effect of multiple fertile females potentially indicates a breakdown of male control as a result of within-group intrasexual mating competition, and greater-than-expected female control over travel movements. As suspected, grey-cheeked mangabeys use neighbors' long-distance calls to maintain a spatial buffer between groups but changes in group movements indicate a conflict between male and female interests.

Extremely thick cranial vaults have been noted as a diagnostic characteristic of Homo erectus since the first fossil of the species was identified, but relatively little work has been done on elucidating its etiology or variation across fossils, living humans, or extant non-human primates. Cranial vault thickness (CVT) is not a monolithic trait, and the responsiveness of its layers to environmental stimuli is unknown. We obtained measurements of cranial vault thickness in fossil hominins from the literature and supplemented those data with additional measurements taken on African fossil specimens. Total CVT and the thickness of the cortical and diploë layers individually were compared to measures of CVT in extant species measured from more than 500 CT scans of human and non-human primates. Frontal and parietal CVT in fossil primates was compared to a regression of CVT on cranial capacity calculated for extant species. Even after controlling for cranial capacity, African and Asian H. erectus do not have uniquely high frontal or parietal thickness residuals, either among hominins or extant primates. Extant primates with residual CVT thickness similar to or exceeding H. erectus (depending on the sex and bone analyzed) include Nycticebus coucang, Perodicticus potto, Alouatta caraya, Lophocebus albigena, Galago alleni, Mandrillus sphinx, and Propithecus diadema. However, the especially thick vaults of extant non-human primates that overlap with H. erectus values are composed primarily of cortical bone, while H. erectus and other hominins have diploë-dominated vault bones. Thus, the combination of thick vaults comprised of a thickened diploë layer may be a reliable autapomorphy for members of the genus Homo.

Pleistocene Paranthropus robustus fossils from Swartkrans have yielded stable isotope values suggesting some foraging on C4 plants possibly including underground storage organs. Dental microwear texture analysis on P. robustus (SK 6, SK 34 and SK 47) from Swartkrans Member 1 is performed to examine whether tooth surface damage from mastication agrees with prior dietary inferences from carbon isotopes. There is considerable variation in textural characteristics among the P. robustus specimens. Specifically, adult SK 34 stands apart from the two subadult specimens, SK 6 and SK 47, suggesting life history could be reflected in patterns of dental microwear texture characteristics, although seasonality and availability of fallback foods may also explain the variation observed in P. robustus. The fossils all exhibit elevated surface texture complexity, resembling the values for Lophocebus albigena and Cebus apella, and to a lesser extent, Pan troglodytes. Paranthropus robustus is dissimilar to primary folivores, such as Trachypithecus cristatus or folivore-frugivores such as Alouatta palliata suggesting leaves comprised very little of its diet. The textural fill volume of P. robustus differs from that observed in extant primates from tropical forests indicating extreme durophagy, perhaps a function of differences in habitat. Ingestion of extraneous grit on the underground parts of plants and from terrestrial resources, perhaps as fallback foods or as dietary staples, may account for these enamel textural properties and may help explain the mixed C3/C4 isotopic signal in P. robustus.

Group size affects many aspects of the ecology and social organization of animals. We investigated group size stability for five primate species in Kibale National Park, Uganda from 1996 to 2011 at three nested spatial scales. Survey data indicated that group sizes did not change for most species, with the exception of red colobus monkeys (Procolobus rufomitratus), in which group size increased at all spatial scales. Mangabey (Lophocebus albigena) group size increased in old-growth forest, but the sample size and increase were small. To augment this survey data, we collected several years of demographic data on three habituated groups of redtail monkeys (Cercopithecus ascanius), eight groups of black-and-white colobus (Colobus guereza), and one red colobus group. The red colobus group increased from 59 to 104 individuals, while redtail monkey and black-and-white colobus group sizes were stable, mirroring our survey results. To understand mechanisms behind group size changes in red colobus versus stability in other primates, we monitored forest dynamics at two spatial scales between 1990 and 2013, considered changes in predator population, and explored evidence of disease dynamics. The cumulative size of all trees and red colobus food trees increased over 24 yr, suggesting that changing food availability was driving group size changes for red colobus, while predation and disease played lesser roles. Overall, our results and evidence of changing primate densities suggest that the Kibale primate community is in a non-equilibrium state. We suggest future conservation and management efforts take this into consideration.

When two social groups are close enough to hear each other' ss hort-range vocalizations but not yet close enough to see each other, they can choose whether to approach to initiate a direct contest. In this study, I evaluated whether expected payoffs and group resource-holding potential affected the likelihood of approach toward a neighboring group during naturally occurring intergroup interactions and experimental playback trials by grey-cheeked mangabeys (Lophocebus albigena). Females approached calling groups at low rates, and only if males did so as well. Groups that had recently arrived (≤30 min) at the interaction location were more likely to approach than groups that were in the interaction location for >30 min. Site residency likely indicates the degree of short-term, local resource exploitation, and explains this pattern of patch defense. There was no evidence that mangabeys defended home range core or peripheral areas, that males defended female mates, or that infant defense affected the likelihood of approach. Surprisingly, resource-holding potential had no effect on patterns of contest initiation, but may influence other aspects of intergroup contests. The unexpected importance of payoff asymmetries, relative to asymmetries in resource- holding potential, points to the need for an expanded theoretical framework.

Why do some primate groups contest access to food resources primarily at territorial borders (periphery defence), whereas others are more likely to contest resources in the centre of the home range (core defence)? One possibility is that central areas contain more food resources and so are more important for core-defending groups, whereas peripheral areas are more valuable for groups that defend territorial boundaries. I tested this hypothesis by analysing the distribution of resources in home ranges and aggressive intergroup interactions for six groups of grey-cheeked mangabeys, Lophocebus albigena, and six groups of redtail monkeys, Cercopithecus ascanius, at the Ngogo site in Kibale National Park, Uganda. Neither mangabeys nor redtails exhibited core or boundary defence in this study; instead, both species appeared to defend discrete feeding sites, and neither the core nor peripheral home range areas consistently contained greater quantities of food. I also compared variables that are frequently used to characterize primate food availability (the feeding value of the interaction site versus food abundance, distribution and patch size) to determine if they are equally accurate in predicting aggressive food defence. Whereas site feeding intensity predicted aggression by redtails, aggression by mangabey males correlated with the abundance and distribution of resources. These results demonstrate the importance of testing multiple aspects of food availability, which can vary in importance among different primate populations. I conclude by proposing a new model of food and range defence in group-living primates that predicts specific relationships between various food characteristics and core, patch and periphery defence.

Animals are predicted to be in closer conspecific proximity during feeding on clumped resources, such as fruits in a tropical rain forest, than when feeding on more dispersed resources, such as leaves or insects. Polyspecific associations are also predicted to affect inter-individual distance because the close proximity of more individuals presumably provides increased protection against predators. We examined the effects of food type and polyspecific association on nearest-neighbor distances of redtail monkeys (Cercopithecus ascanius) in the rain forest of Kibale National Park, Uganda. When redtails consumed fruit, they were closer to conspecific nearest neighbors than when they consumed leaves or insects. When any of the other five monkey species were close or intermingled, redtail monkeys were farther from conspecific nearest neighbors than when they were not in polyspecific associations; however, this effect was apparently driven by redtail associations with grey-cheeked mangabeys (Lophocebus albigena). The aggression mangabeys exhibit to aerial predators may explain this observation. Our results imply a complex relationship between food distribution, predation risk, polyspecific association and spatial patterns that can be explored further in multiple taxa.

Late Pliocene Procynocephalus subhimalayanus from the Upper Siwaliks, India is known from only three specimens. The dietary proclivities of this taxon have implications for reconstructing the paleoecology of the Upper Siwaliks. The dental microwear texture properties of Procynocephalus are compared to those from extant tropical forest primates including Alouatta palliata (n = 11), Cebus apella (n = 13), Gorilla gorilla (n = 9), Lophocebus albigena (n = 15) and Trachypithecus cristatus (n = 12). Dental microwear textures are generated by scanning the surface enamel of Facet 9 using white-light confocal microscopy at 100x. Four variables were extracted from scale-sensitive fractal analysis, and the data were ranked before ANOVA with post-hoc tests of significance and multivariate analyses were performed. Procynocephalus clusters closest to Lophocebus, Cebus and some Gorilla specimens suggesting hard-object feeding characterized a portion of its diet. The dental microwear texture of Procynocephalus supports interpretations of widespread grasslands of the Late Pliocene Kansal Formation (Pinjor zone). The extreme enamel complexity characterizing Procynocephalus may derive from consumption of underground storage organs, or other foods with high grit loads. Foods consumed near ground level carry a heavy load of abrasive minerals possibly contributing to greater enamel surface complexity and textural fill volume.

Wild animal meat represents an important source of protein for many people in central Africa. Also known as bushmeat, this meat commodity is derived from wild animals hunted under uncontrolled conditions, transported to distant markets under rudimentary or no hygienic methods, and often eviscerated >24 hr after death. Considering the plausible role of wildlife as a reservoir for bacterial zoonotic pathogens, bushmeat may be an important public health risk in Central Africa. This cross-sectional survey served to evaluate the presence of Campylobacter, Salmonella, and Shigella in the muscle tissue of 128 wild animal carcasses from several hunted wildlife species (guenons [Cercopithecus spp.], collared mangabeys [Cercocebus torquatus], gray-cheeked mangabeys [Lophocebus albigena], African crested porcupines [Atherurus africanus], duikers [Cephalophus spp.], and red river hogs [Potamocherus porcus]) sold in two markets of Port-Gentil, Gabon, in July and August 2010. Salmonella was detected from one carcass; no Campylobacter or Shigella was detected. If Campylobacter and Shigella were present, the maximum expected prevalence was estimated at 6% and 1%, respectively. In light of such very low apparent muscle contamination levels, bushmeat likely does not represent a health risk per se with respect to Campylobacter, Salmonella, or Shigella. However, because carcass evisceration and skinning can take place within households prior to consumption, consumers should follow strict hygiene and food safety practices to avoid potential health hazards associated with the handling, preparation, or consumption of bushmeat.

3D dental microtexture analysis is a powerful tool for reconstructing the diets of extinct primates. This method is based on the comparison of fossils with extant species of known diet. The diets of primates are highly diversified and include fruits, seeds, grass, tree leaves, bark, roots, tubers, and animal resources. Fruits remain the main component in the diets of most primates. We tested whether the proportion of fruit consumed is correlated with dental microtexture. Two methods of microtexture analysis, the scale-sensitive fractal analysis (SSFA) and the Dental Areal Surface Texture Analysis (DASTA; after ISO/FDIS 25178-2), were applied to specimens of eight primate species (Alouatta seniculus, Gorilla gorilla, Lophocebus albigena, Macaca fascicularis, Pan troglodytes, Papio cynocephalus, Pongo abelii, Theropithecus gelada). These species largely differ in the mean annual proportion of fruit (from 0 to 90%) in their diet, as well as in their consumption of other hard items (seeds, bark, and insect cuticles) and of abrasive plants. We find the complexity and heterogeneity of textures (SSFA) to correlate with the proportion of fruits consumed. Textural fill volume (SSFA) indicates the proportion of both fruits and other hard items processed. Furthermore, anisotropy (SSFA) relates to the consumption of abrasive plants like grass and other monocots. ISO parameters valley height, root mean square height, material volume, density of peaks, and closed hill and dale areas (DASTA) describe the functional interaction between food items and enamel facets during mastication. The shallow, plastic deformation of enamel surfaces induced by small hard particles, such as phytoliths or dust, results in flat microtexture relief, whereas the brittle, deep fracture caused by large hard items such as hard seeds creates larger relief.

This article explores spatial and temporal changes in diurnal primate abundance and behavior in response to hunting, logging, and conservation at the Dzanga Sangha Dense Forest Reserve (RDS), Central African Republic over time. We use a combination of line-transect surveys in 2002 and 2009 (N = 540 km) and ethnographic interviews (N = 210) to investigate changes in the status of cercopithecines and colobines at RDS, with additional comparisons to earlier work. This protected area was lightly logged in the 1970s and the park was gazetted in 1990, with multiple-use reserve sectors allocated. Since the park's inception, hunting and the trade of primates have increased, along with human migration, greater accessibility of arms, and reduction of preferred ungulate prey. Primates have declined in both the park and reserve sectors. Our data further suggest that at RDS hunting has had a greater impact on primate diversity and abundance than logging. We have identified changes in species-specific vulnerability to hunting over time, with Cercopithecus nictitans and Lophocebus albigena initially having appeared to be relatively resistant to hunting pressure in 2002. However, subsequently as gun hunting has increased at RDS, these species have become vulnerable. Although monkeys at RDS have been responding behaviorally to increased gun hunting, they are not able to keep pace with changing hunting practices. This study allows us to begin to understand synergistic impacts of hunting and logging, necessary if we are to recommend strategies to better secure the future of primates in multiuse protected areas. Am. J. Primatol. 74:602–612, 2012. © 2012 Wiley Periodicals, Inc.

Habitat disturbance due to anthropogenic activities is a source of acute and chronic energetic stress in wild animals, including primates. Physiological responses to stress can compromise growth and reproduction, increase susceptibility to infection and lead to deleterious effects on health and conservation efforts. However, physiological measures of energetic stress in association with habitat disturbance are uncommon, especially for wild primate species. Here, we report differences in the stress hormone cortisol in two subpopulations of wild gray-cheeked mangabeys (Lophocebus albigena) inhabiting disturbed and undisturbed forest areas of Kibale National Park, Uganda. Cortisol levels were assessed via opportunistically and noninvasively collected urine samples using previously validated methods. We hypothesized that mangabeys in disturbed forest (DF) areas would experience greater stress and therefore exhibit higher average cortisol levels than conspecifics in nearby relatively undisturbed forest areas (UF). As predicted, mangabeys in the disturbed area had significantly higher cortisol levels (unpaired t-test of log transformed data, t = 4.88, d.f. = 108, P

Testosterone can be expected to play a significant role in mediating behavior and life history in social animals, but the number of species with data from the wild is still too small to make generalizations. We investigated the influence of social factors (social status, aggression, and reproductive females) and environmental variation (rainfall and temperature) on fecal testosterone concentrations in wild male gray-cheeked mangabeys (Lophocebus albigena) living in five groups in Kibale National Park, Uganda. This species is phylogenetically closely related to baboons, but is arboreal, with multi-male, multi-female groups rarely exceeding 20 individuals. We analyzed 358 fecal samples from 21 adult males. We found that the highest-ranking males had the highest testosterone concentrations while immigrant males had the lowest testosterone concentrations. Aggression was not correlated with testosterone levels. The presence of females with sexual swellings at their most tumescent stage increased testosterone concentrations in all males. Finally, individuals tended to have lower testosterone when the temperature was higher.

Studies of primate foraging efficiency during the exploration of new areas can provide important insights into the adaptive value of long-term spatial memory. After 6 yr of observation of a group of gray-cheeked mangabeys (Lophocebus albigena johnstonii) in Kibale National Park, Uganda, we observed exploration of a new area, followed 7 mo later by a group split. We recorded their ranging and foraging behavior for 22 mo after the first exploration. Controlling for weather variables, we found that mangabeys moved longer daily travel distances, explored more area per day, and had larger group spreads in the new area compared to the old area in both parent and daughter groups. The increase in search swath in the new area likely enabled the monkeys to counteract their lack of knowledge of food locations in the new area, as the efficiency in finding fruit in general did not differ between the old and new areas. We did, however, find a lower efficiency in finding fruit from preferred fig trees whose edibility could not be assessed by visual cues in the new area. Fig finding efficiency remained lower, even when we controlled for potential differences in fig density. In addition, mangabeys traveled and foraged less often on the ground in the new compared to the old area. However, when the monkeys became more familiar with the new area, terrestrial behavior increased. Our results are consistent with the hypothesis that when monkeys move into an area in which they have no experience, an absence of knowledge acquired via long-term spatial memory decreases their foraging efficiency.

Zusammenfassung Im Reservat des Kibale Forest in Uganda wurden im Mai—Juni 1971 die taglichen Marschrouten und raumlichen Zerstreuungen einer freilaufenden Gruppe von Cercocebus albigena untersucht. Die raumliche Organisation dieser Gruppe unterschied sich in mehreren Hinsichten von der anderer Regenwaldaffen. Wahrend diese zum Beispiel in ziemlich engen Gebieten leben, bewohnt diese Cercocebus-Gruppe mehr als 34 ha, also ahnlich viel wie Bewohner der offenen Steppe. Ebenso entsprachen die taglichen Marschrouten und die mittlere Entfernung zwischen den Mitgliedern dieser Gruppe eher denen der am Boden in offener Landschaft lebenden Affen. Diese Ergebnisse zeigen, das sich baumlebende Regenwaldbewohner in Wohngebietsgrose, taglichen Wanderungen und Gruppendichte betrachtlich unterscheiden. Theorien oder Verallgemeinerungen, das die soziale Organisation waldlebender Arten weniger veranderlich sei als die von offener Landschaft, mussen erneut durchdacht werden.

Recently, we demonstrated that the highest densities of fruit pulp are located in the uppermost zones of tree crowns. Since heterogeneous distributions of depletable food is theorized to foster contest competition, we tested three hypotheses involving rank differences among species of arboreal frugivores: (1) In the absence of competitors, species tend to feed in higher strata of tree crowns; (2) interspecific contest competition occurs through monopolization and usurpation of feeding sites in these higher strata; and (3) subordinate species decrease their feeding height and ingestion rate when dominants enter the food patch. To test these hypotheses, we observed chimpanzees (Pan troglodytes), red-tailed monkeys (Cercopithecus ascanius), blue monkeys (Cercopithecus mitis), and gray-cheeked mangabeys (Lophocebus albigena) in Kibale National Park, Uganda. We found that: (1) all four primates fed preferentially in upper tree crowns when alone, (2) dominant species monopolized and aggressively usurped the upper crown when co-feeding with subordinates and the latter retreated below the middle of tree crowns, (3) in the presence of dominant species, subordinate species showed lower standardized feeding height and modified their food intake rates, while dominants were not affected by the subordinate species, (4) subordinates moved down at the arrival of and up at the departure of dominants, and (5) the presence of folivores in the tree did not affect the feeding height of a frugivore, even through folivores were socially dominant. Contrary to expectations, we found that red-tailed monkeys decreased their movements between successive fruits that they ate in the presence of blue monkeys compared to when they were feeding alone, perhaps to avoid disturbing dominants and attracting aggression or because they ingested more semi-ripe and green unripe fruits, i.e., more food of lower quality.

Authors of socioecological models propose that food distribution affects female social relationships in that clumped food resources, such as fruit, result in strong dominance hierarchies and favor coalition formation with female relatives. A number of Old World monkey species have been used to test predictions of the socioecological models. However, arboreal forest-living Old World monkeys have been understudied in this regard, and it is legitimate to ask whether predominantly arboreal primates living in tropical forests exhibit similar or different patterns of behavior. Therefore, the goal of our study was to investigate female dominance relationships in relation to food in gray-cheeked mangabeys (Lophocebus albigena). Since gray-cheeked mangabeys are largely frugivorous, we predicted that females would have linear dominance hierarchies and form coalitions. In addition, recent studies suggest that long food site residence time is another important factor in eliciting competitive interactions. Therefore, we also predicted that when foods had long site residence times, higher-ranking females would be able to spend longer at the resource than lower-ranking females. Analyses showed that coalitions were rare relative to some other Old World primate species, but females had linear dominance hierarchies. We found that, contrary to expectation, fruit was not associated with more agonism and did not involve long site residence times. However, bark, a food with a long site residence time and potentially high resource value, was associated with more agonism, and higher-ranking females were able to spend more time feeding on it than lower-ranking females. These results suggest that higher-ranking females may benefit from higher food and energy intake rates when food site residence times are long. These findings also add to accumulating evidence that food site residence time is a behavioral contributor to female dominance hierarchies in group-living species.

Intensive study of arboreal forest-dwelling primates and their predators in Africa is increasingly revealing that crowned eagles (Stephanoaetus coronatus) are major predators of primates. Gray-cheeked mangabeys (Lophocebus albigena) are overrepresented in the diets of crowned eagles in Kibale National Park, Uganda, and adult male mangabeys are represented more than females. We focused on the behavior of adult male gray-cheeked mangabeys living in social groups in Kibale National Park (1) to clarify the interactions between mangabeys and eagles that might put adult males at greater risk and (2) to better understand individual variation in behavioral responses to predators. Adult male mangabeys in five groups responded to observer-confirmed presence of crowned eagles 88 times over a 13-month period. While all males gave alarm calls, only the highest-ranking male in each of four groups chased eagles. These males had elevated levels of fecal cortisol metabolites in the days immediately after they engaged in active defense, suggesting that they perceived such behavior as risky. In the one group where male ranks were unstable and there were no infants, no male was observed to chase eagles. We suggest that males pursue the dangerous tactic of chasing eagles only when they are likely to have offspring in the group. Males in larger groups also spent less time alarm calling to crowned eagles (from first to last call in a group), and our observations confirmed that the duration of their alarm calls was related to eagle presence. Thus, eagles spent less time around larger mangabey groups. Alarm calling by adult male mangabeys may signal to this ambush predator that it has been detected and should move on.

The power stroke of mastication has been traditionally divided into two parts, one which pre- cedes centric occlusion, and the other which follows it— ''Phase I'' and ''Phase II,'' respectively. Recent studies of primate mastication have called into question the role of Phase II in food processing, as they have found little muscle activity or accompanying bone strain following centric occlusion. That said, many researchers today look to Phase II facets to relate diet to patterns of dental microwear. This suggests the need to reevaluate micro- wear patterns on Phase I facets. Here we use texture analysis to compare and contrast microwear on facets representing both phases in three primate species with differing diets (Alouatta palliata, Cebus apella, and Lophocebus albigena). Results reaffirm that microwear patterns on Phase II facets better distinguish taxa with differing diets than do those on Phase I facets. Further, differences in microwear textures between facet types for a given taxon may themselves reflect diet. Some possible explanations for differences in microwear textures between facet types are proposed. Am J Phys Anthropol 137:485-490, 2008. V C

Primate female allogrooming models based on biological markets theory predict that grooming is "time matched" within bouts, that is, the amount of time the first female grooms predicts the amount of time the second one grooms. The models also predict that when female--female contest competition is weak, grooming is traded for grooming, but when female--female contest competition is strong, grooming may be traded for other commodities such as feeding tolerance, and grooming discrepancy between members of dyads is rank related. We tested these predictions using data collected from adult and subadult female gray-cheeked mangabeys (Lophocebus albigena) (N = 26) in 5 groups in Kibale National Park, Uganda. We found that, overall, females reciprocated in 33% of grooming bouts. Among reciprocated bouts, females in all 5 groups showed time matching. In 2 groups, we also found rank-related grooming discrepancies but showing opposite patterns to each other. Consistent with predictions based on biological markets theory, these groups may have been under greater feeding competition, revealed more by adjustments in ranging behavior than increased agonistic rates. Although these results support current allogrooming models, they also suggest that the models may become more robust if the influence of scramble competition is incorporated. In addition, they emphasize the flexibility and dynamic nature of female competitive relationships within the same population of primates. Copyright 2009, Oxford University Press.

Reproductive tactics of males can change with individual quality, relat-edness and social structure. Here we describe the behaviours of malegrey-cheeked mangabeys towards other males, and females and theiroffspring (Lophocebus albigena) in relation to male status (high-rank-ing⁄low-ranking⁄transient) and group composition in Kibale NationalPark, Uganda. High-ranking males had the highest mating success, fre-quency of loud calls, mate guarding and aggression towards females andmales. Only transient males were often observed to be aggressivetowards juveniles, while some high-ranking males provided infant care.Mating tactics of high-ranking males varied greatly among the five stud-ied groups, probably as a function of the intensity of male–male compe-tition. These results are discussed with regard to the role of male–malecompetition and behaviours that could affect female mate choice as tac-tics to obtain reproductive success. Ethology Ethology 114 (2008) 851–862 a 2008 The AuthorsJournal compilation a 2008 Blackwell Verlag, Berlin

Female sexual strategies affect male strategies and can play an important role in shaping mating systems. We investigated female sexual behaviour within five groups of grey-cheeked mangabeys in Kibale National Park, Uganda, and tested the hypothesis that females exhibit mate choice using as indications the prevalence of (1) females soliciting matings by presenting to males and (2) females refusing to mate with approaching males. In addition, we describe how these behaviours as well as grooming and copulation calls are distributed over high-ranking, low-ranking and migrating males and discuss these patterns with regard to trade-offs that could play a roll in female mate choice in multi-male groups. Females were promiscuous and initiated almost half of the matings, with both resident and migrating males. More than half of male mating approaches were refused by peak females. Female mate choice in this species may depend on individual female preferences, oestrus phase and male tactic.

Revising the grey-cheeked mangabeys (Lophocebus albigena group) in the light of the Phylogenetic Species Concept reveals more taxonomic diversity than was formerly suspected. The three subspecies recognized by Groves (1978) are diagnosably distinct, and are here upgraded to species rank. Most significantly, the mangabeys of Uganda, not recognized as distinct at all in the 1978 revision, are now shown to constitute a fourth species, Lophocebus ugandae (Matschie, 1912), which is apparently confined to Uganda, and as such probably Uganda's only endemic primate

Using the line transect methods, I studied the primate density at Ngogo, Kibale National Park, Uganda for 18 months. Comparisons with other studies show that the population of red colobus monkeys (Procolobus rufomitratus) and blue monkeys (Cercopithecus mitis) is declining, whereas the populations of black-and-white colobus (Colobus guereza), red-tailed monkeys (Cercopithecus ascanius), grey-cheeked mangabeys (Lophocebus albigena), baboons (Papio anubis), and chimpanzees (Pan troglodytes) remain constant or slightly increase. In this paper, I compare data on density from this study to data from previous and recent censuses at Ngogo and with data from other sites in the Kibale forest to examine the stability of primate populations. Furthermore, I test the hypothesis that the changes in red colobus and blue monkey density are due to changes in the forest structure and abundance of their most selected feeding trees, and show that changes in forest composition cannot account for changes in their red colobus abundance, but that hunting by chimpanzees provides a reasonable explanation. Am. J. Primatol. 69:1030–1044, 2007. © 2007 Wiley-Liss, Inc.

We compare cortisol levels in monkeys at two sites with varying habitat disturbance within Kibale National Park, Uganda. Both species have higher cortisol levels at the less disturbed of the two sites. Factors such as social dynamics or predation may be responsible, illustrating the subtleties of wild primate ecophysiology., Non-invasive measurement of urinary cortisol is a proven method of evaluating the impact of environmental stressors on wild primates. Variation in cortisol concentrations can reflect physiological stress, and prolonged elevation of circulating cortisol can significantly affect individual and population-level health. In a previous study, we found that urinary cortisol concentrations in grey-cheeked mangabeys (Lophocebus albigena) were higher at a highly disturbed site (Mainaro) in Kibale National Park, Uganda compared with a minimally disturbed site (Ngogo) in the same habitat. Here, we expand on this research, reporting on cortisol concentrations in two other cercopithecid monkeys (Cercopithecus ascanius and Piliocolobus rufomitratus) at the same two sites. We hypothesized that C. ascanius would show no difference between sites, given its preference for secondary forests, while P. rufomitratus would have higher cortisol concentrations at the disturbed site. Contrary to expectations, both species exhibited significantly higher cortisol concentrations at Ngogo (minimally disturbed) compared with Mainaro (disturbed). We suggest that these results may be caused by inter- or intragroup social dynamics, intersite differences in predation rate, fruit/food availability and chemistry, or a combination of these factors. These initial evaluations of urinary cortisol concentrations provide testable hypotheses on habitat disturbance and Kibale primate ecophysiology.

International audience; Intestinal parasites may constitute an important evolutionary and ecological force. We aimed to identify social, physiological, and environmental factors that correlate with intestinal parasite infections in adult male gray-cheeked mangabeys (Lophocebus albigena). We analyzed 102 fecal samples collected from 18 adult males over 19 mo for the incidence (proportions of samples with parasites) and intensity (total number of parasites per gram of feces) of infection of nematodes relative to social status, fecal glucocorticoid and testosterone metabolites, group size, and rainfall, all of which are factors that earlier studies suggested can be important mediators of parasite load. Parasite incidence was greater in immigrant males compared to low- and high-ranking males whereas parasite intensity was greater in immigrant males and low-ranking males compared to high-ranking males. Fecal samples with more parasites had higher concentrations of fecal glucocorticoid and testosterone metabolites than those with fewer parasites. As immigrant males had a greater incidence of parasites and higher concentrations of both metabolites than resident males, this profile appears to fit immigrant males best. We also found higher nematode intensities in mid-sized groups and during periods with more rainfall. Our results suggest that it will be fruitful for future studies to explore the role of immigrant males as spreaders of intestinal parasites.

International audience; Identifying the causes of differential reproductive success is key to understanding natural selection and the forces of selection operating on animals. Here we present results from a 9-yr (2004–2012) study of female reproductive performance in relation to mother’s age and rank, presence of immigrant males, rainfall, and fig fruit abundance in four groups of gray-cheeked mangabeys (Lophocebus albigena) in Kibale National Park, Uganda. We found that females had a rank- and age-specific reproductive pattern, with high-ranking females maturing earlier, having their first births earlier, and exhibiting significantly slower reproductive aging than low-ranking females. We also found that both immigrant and resident males were associated with higher birth rates. Finally, we found that reproduction was aseasonal and did not correlate with rainfall, but that births correlated positively with the abundance of fruits of Ficus spp. Our results show broad similarities between arboreal, forest-dwelling gray-cheeked mangabeys and their more terrestrial, open habitat-dwelling papionin relatives in the importance of dominance rank in estrous cycle initiation, first reproduction, and reproductive aging.

We investigated the ranging behaviour of two groups of wild mangabey monkeys (sooty mangabeys, Cercocebus atys atys, and grey-cheeked mangabeys, Lophocebus albigena johnstoni) relative to a number of preselected target trees within their home range. We observed the groups' visiting patterns and speed when they approached within a critical distance of a target tree as a function of the tree's fruiting state. For both groups, the likelihood of coming into sight or actually entering these trees was significantly higher if fruit was available. Target trees with fruit were also approached significantly faster than were trees without fruits. These behavioural differences were unlikely to be the result of auditory, visual or olfactory cues available over long distances, suggesting that monkeys relied on spatial memory to relocate fruit trees and distinguish between trees that had and had not carried fruit in the immediate past. Results further indicated that the monkeys clearly distinguished between different types of fruit-bearing target trees. We suggest that the monkeys used memory of previous feeding experience to assess each tree's differences and were able to anticipate changes in fruit quality. We found no evidence that individuals belonging to a particular age or sex class led the group towards trees with fruit more often than did others. settings.

Dental microwear analysis is commonly used to infer aspects of diet in extinct primates. Conventional methods of microwear analysis have usually been limited to two-dimensional imaging studies using a scanning electron microscope and the identification of apparent individual features. These methods have proved time-consuming and prone to subjectivity and observer error. Here we describe a new methodological approach to microwear: dental microwear texture analysis, based on three-dimensional surface measurements taken using white-light confocal microscopy and scale-sensitive fractal analysis. Surface parameters for complexity, scale of maximum complexity, anisotropy, heterogeneity, and textural fill volume offer repeatable, quantitative characterizations of three-dimensional surfaces, free of observer measurement error. Some results are presented to illustrate how these parameters distinguish extant primates with different diets. In this case, microwear surfaces of Cebus apella and Lophocebus albigena, which consume some harder food items, have higher average values for complexity than do folivores or soft fruit eaters.

Temperature and solar radiation are known to influence maturation of fruits and insect larvae inside them [1–8]. We investigated whether gray-cheeked mangabeys (Lophocebus albigena johnstonii) of Kibale Forest, Uganda, take these weather variables into account when searching for ripe figs or unripe figs containing insect larvae. We predicted that monkeys would be more likely to revisit a tree with fruit after several days of warm and sunny weather compared to a cooler and more cloudy period. We preselected 80 target fig trees and monitored whether they contained ripe, unripe, or no fruit. We followed one habituated monkey group from dawn to dusk for three continuous observation periods totalling 210 days. Whenever the group came within a 100 m circle of a previously visited target tree for a second time, we noted whether or not individuals proceeded to the trunk, i.e., whether they ‘‘revisited’’ or simply ‘‘bypassed’’ the tree. We found that average daily maximum temperature was significantly higher for days preceding revisits than bypasses. The probability of a revisit was additionally influenced by solar radiation experienced on the day of reapproach. These effects were found only for trees that carried fruit at the previous visit but not for trees that had carried none. We concluded that these nonhuman primates were capable of taking into account past weather conditions when searching for food. We discuss the implication of these findings for theories of primate cognitive evolution.

Primate censuses were conducted in a mosaic of colonizing (two locations) and old-growth forests using line transect methods at the Ngogo study site, Kibale National Park, Uganda. Black and white colobus monkeys (Colobus guereza) were encountered more frequently in the colonizing forests than in the old growth forest, while chimpanzees (Pan troglodytes) were encountered more frequently in the old growth forest than in colonizing forests. Although not significant, results suggest that blue monkeys (Cercopithecus mitis) frequented colonizing forests more often than old growth forest. The encounter rates of mangabey (Lophocebus albigena), and redtail (Cercopithecus ascanius) groups were ambiguous with their density being higher in some colonizing forests but not others as compared to old-growth forest. No significant differences were detected for baboons (Papio anubis), L'hoest's (Cercopithecus lhoesti), and red colobus monkeys (Piliocolobus tephroscales). The conversion of forests to farmland is one of the major problems encountered in primate conservation. This study shows that secondary forests replacing anthropogenic grasslands have the potential of supporting some primate species such as black and white colobus, redtail monkeys, and possibly blue monkeys. Therefore, such areas should not be given up but should be conserved for the benefit of primates that can survive in secondary forests; as the forests mature further, primate species that are adapted to old growth forest will colonize the area provided there is a nearby source.

Conservation of wildlife populations requires extensive knowledge of their habitat requirements, efficient methods to evaluate habitat quality, and an understanding of the value of fragments and edges. Kibale National Park, Uganda has areas that differ in the densities of 2 species of frugivorous monkeys—Cercopithecus mitis and Lophocebus albigena—including one on an edge and forest fragments outside the park that lack both species. We compared the basal area densities of important food trees with primate densities. The density of Cercopithecus mitis correlates most strongly with the basal area density of all types of food trees combined. The density of Lophocebus albigena does not correlate with the basal area densities of any category of food trees or with fruit availability. An index of their density—number of groups seen per km walked—correlates to fruit availability but with marginal significance. Lack of a relationship between the basal area densities of food trees and density of Lophocebus albigena may be the result of a mismatch in scale between the forest area measured and their large home ranges. We compared the unused area of forest to the other areas of the forest and the fragments and found it had higher basal area densities in all food tree categories for both species than the fragments and lower basal area densities of most categories than the other parts of the forest, indicating that the fragments are poor quality and would probably be unused even if dispersal were likely.