Food partitioning among Malagasy primates

Summary Food partitioning among lemurs was studied in relation to food patch size and plant chemistry in the eastern rainforest and a western deciduous forest of Madagascar. Patch size (i.e. crown diameter of food trees) is significantly correlated with group body weight of different lemur species. But intraspecific variability is high and prevents effective species separation. Chemical analyses of more than 400 plant parts eaten by seven different lemur species revealed major differences in their food choice with respect to protein concentrations, condensed tannins and alkaloids. Among the leaf eating lemurs discriminant analysis segregates three groups à two species based on chemical characteristics of their food. Whereas differences in food chemistry are pronounced between groups they are lacking between the two species within each group. The two species of each group avoid interference competition by different activity rhythms. Actual competition for slowly renewable resources such as leaves and fruit, however, can not be reduced by different activities. Here interspecific differences in gross categories of food, food species composition and different habitat utilization due to other constraints may contribute to the possible coexistence of species. Thus interspecific differences in food selection in relation to primary and secondary plant chemicals is an integrated part of the mechanisms allowing several primate species to coexist in sympatry.     

Economic behaviours among non-human primates

Do we have any valid reasons to affirm that non-human primates display economic behaviour in a sufficiently rich and precise sense of the phrase? To address this question, we have to develop a set of criteria to assess the vast array of experimental studies and field observations on individual cognitive and behavioural competences as well as the collective organization of non-human primates. We review a sample of these studies and assess how they answer to the following four main challenges. (i) Do we see any economic organization or institutions emerge among groups of non-human primates? (ii) Are the cognitive abilities, and often biases, that have been evidenced as underlying typical economic decision-making among humans, also present among non-human primates? (iii) Can we draw positive lessons from performance comparisons among primate species, humans and non-humans but also across non-human primate species, as elicited by canonical game-theoretical experimental paradigms, especially as far as economic cooperation and coordination are concerned? And (iv) in which way should we improve models and paradigms to obtain more ecological data and conclusions? Articles discussed in this paper most often bring about positive answers and promising perspectives to support the existence and prevalence of economic behaviours among non-human primates.This article is part of the theme issue ‘Existence and prevalence of economic behaviours among non-human primates’.     

Avoiding commitment: cathemerality among primates

Cathemeral animals distribute their activity more or less uniformly between the dark and light phases of the 24-hour day. This activity pattern is quite widely observed among major mammal taxa, although the number of species involved is relatively low. Among primates, cathemerality is seen principally, though not uniquely, in the strepsirhine (“lower primate”) family Lemuridae; it is ubiquitous in the genus Eulemur, among species of which it seems to be a stable activity pattern with a history going back at least 8 - 12 million years. Nocturnal primates have visual systems that accentuate sensitivity to light over visual acuity, showing large cornea size, high rod:cone ratios and large numbers of photoreceptors relative to ganglion cells. Diurnal forms do the reverse, while Eulemur species are intermediate in these respects, suggesting substantial accommodation of the visual system to the cathemeral lifestyle. Studies of one Eulemur species have revealed that its cathemerality is underpinned by a robust endogenous circadian timing mechanism with a free-running periodicity of over 25 hours. The lemurs appear to be entrained to the 24-hour day by the light/dark cycle, plausibly with dusk as the primary zeitgeber. The causes of cathemerality have been sought in such environmental influences as predator avoidance, energy conservation, dietary quality, and interspecies feeding competition. All of these factors seem to be relevant to the cathemeral lifestyle, but none appears to be a crucial determinant. Nothing is known of the underlying neural mechanisms that facilitate the lemurs' accommodation to the extremes to which 24-hour activity exposes them.     

Dental eruption sequence among colobine primates

Dental development is one aspect of growth that is linked to diet and to life history but has not been investigated among colobines since the work of Schultz [1935]. This study establishes the dental eruption sequence for several colobine species and compares it to that of other catarrhines. The mandibles and maxillae of two hundred and four juvenile colobine specimens were scored for presence or absence of permanent teeth and for stages of partial eruption. Eruption was defined as ranging between tooth emergence (any part of a tooth crown above the alveolar margin) and full occlusion, with three intermediate levels manifest between these boundaries. In African colobines, represented by C. guereza, C. angolensis and P. badius, M2 erupts before I2, and in C. angolensis it also erupts before I1. The canine is delayed, erupting after the premolars in females and after M3 in males. Asian colobines show greater diversity in eruption sequences. Nasalis shows no early eruption of the molars and is very similar to Macaca. In Trachypithecus and Pygathrix M(2) erupts before I(2). The canine in Trachypithecus is delayed, erupting after the premolars and, in some males, after M3. In Presbytis M2 erupts before both incisors; M3 erupts before C in both sexes, and often before both premolars. Although the actual timing of eruption is unknown, all colobine species examined except N. larvatus showed some degree of relatively early eruption of M2 and M3. The lack of this tendency in Nasalis sets this genus apart from all other colobines represented in this study. Dental eruption sequence is thought to reflect life history patterns. Early molar eruption in colobines was thought by Schultz (1935) to be a primitive character reflecting shorter life history. Faster growth rates found in folivorous primates have been interpreted as being related to an adaptation to folivory (Leigh 1994), and early eruption of molars may be part of this dietary specialization. The relationships between dental development and both diet and life history are investigated.     

Antigenic similarities to HCG subunits among chorionic gonadotropins of nonhuman primates.

Comparison of antigenic similarity between human chorionic gonadotropin (HCG) subunits and the chorionic gonadotropins of six species of nonhuman primates indicates marked similarity of antigenic determinants between both subunits of HCG and the chorionic gonadotropins of chimpanzees, gorillas, and orangutans. Antisera to HCG subunits (alpha or beta) did not cross-react with the chorionic gonadotropins of baboons, macaques, or marmosets. Because of the relative availability of chimpanzees for laboratory studies, we suggest that chimpanzees may be the optimal nonhuman primate model for determining the advisability of vaccinations in man using conjugates of HCG fragments to achieve fertility control or for suppression of HCG-producing neoplasms.     

The function of peaceful post-conflict contacts among primates

Reconciliation has been the subject of considerable research in the last decade, and researchers have demonstrated that in many species of Old World monkeys and apes former opponents are more likely to engage in friendly interactions in the minutes that follow conflicts than they are at other times.de Waal has suggested that the function of these interactions is to mend relationships that have been damaged by conflict. Although peaceful post-conflict interactions are thought to have long-term effects upon the nature of social relationships, behavioral evidence presently indicates that the effects of these interactions may be limited to the post-conflict period. Theoretical considerations also raise some doubts about whether the relationship-repair hypothesis is cogent. Data that demonstrate that peaceful post-conflict interactions facilitate peaceful interactions and relieve victim's uncertainty and anxiety about whether conflict will be continued suggest that peaceful post-conflict interactions may be a means to reestablish contact with former opponents. Thus, they appear to function as predictive signals that the actor is going to stop fighting and behave peacefully. Such signals may be important in a broad range of social contexts.     

Grooming reciprocation among female primates: a meta-analysis

The theory of reciprocal altruism offers an explanation for the evolution of altruistic behaviours among unrelated animals. Among primates, grooming is one of the most common altruistic behaviours. Primates have been suggested to exchange grooming both for itself and for rank-related benefits. While previous meta-analyses have shown that they direct their grooming up the hierarchy and exchange it for agonistic support, no comprehensive evaluation of grooming reciprocation has been made. Here we report on a meta-analysis of grooming reciprocation among female primates based on 48 social groups belonging to 22 different species and 12 genera. The results of this meta-analysis showed that female primates groom preferentially those group mates that groom them most. To the extent allowed by the availability of kinship data, this result holds true when controlling for maternal kinship. These results, together with previous findings, suggest that primates are indeed able to exchange grooming both for itself and for different rank-related benefits.     

Introduction to the primates

Introduction to the Primates. By Daris R. Swindler. 1998. Seattle, Washington: University of Washington Press. 284 pp. ISBN 0-295-97704-3. $22.00 (paper).     

The Evolution of satellite III DNA subfamilies among primates

We demonstrate that satellite III (SatIII) DNA subfamilies cloned from human acrocentric chromosomes arose in the Hominoidea superfamily. Two groups, distinguished by sequence composition, evolved nonconcurrently, with group 2 evolving 16-23 million years ago (MYA) and the more recent group 1 sequences emerging approximately 4.5 MYA. We also show the relative order of emergence of each group 2 subfamily in the various primate species. Our results show that each SatIII subfamily is an independent evolutionary unit, that the rate of evolution is not uniform between species, and that the evolution within a species is not uniform between chromosomes.     

Craniodental variation among Macaques (Macaca), nonhuman primates

Background  

In terms of structure and function, the skull is one of the most complicated organs in the body. It is also one of the most important parts in terms of developmental and evolutionary origins. This complexity makes it difficult to obtain evolutionary assessments if, as is usually the case with fossils, only part of the skull is available. For this reason this study involves a set of comparisons whereby the smallest functional units are studied first, and these built up, through a triple-nested hierarchical design, into more complex anatomical regions and eventually into the skull-as-a-whole. This design has been applied to macaques (Macaca) in order to reveal patterns of variation at the different levels. The profiles of such variation have been obtained both within and between species. This has lead to a search for the skull parts that have undergone similar selection pressures during evolution and comparable development patterns in both ontogeny and phylogeny.     

Sexual dimorphism in relative sacral breadth among catarrhine primates

As the sacrum contributes to the size and shape of the birth canal, the sexually dimorphic sacrum of humans is frequently interpreted within obstetric contexts. However, while the human sacrum has been extensively studied, comparatively little is known about sacral morphology in nonhuman primates. Thus, it remains unclear whether sacral sexual dimorphism exists in other primates, and whether potential dimorphism is primarily related to obstetrics or other factors such as body size dimorphism. In this study, sacra of Homo sapiens, Hylobates lar, Nasalis larvatus, Gorilla gorilla, Pongo pygmaeus, Pan troglodytes, and Pan paniscus were evaluated for sexual dimorphism in relative sacral breadth (i.e., the ratio of overall sacral breadth to first sacral vertebral body breadth). Homo sapiens, H. lar, N. larvatus, and G. gorilla exhibit dimorphism in this ratio. Of these, the first three species have large cephalopelvic proportions, whereas G. gorilla has small cephalopelvic proportions. P. pygmaeus, P. troglodytes, and P. paniscus, which all have small cephalopelvic proportions, were not dimorphic for relative sacral breadth. We argue that among species with large cephalopelvic proportions, wide sacral alae in females facilitate birth by increasing the pelvic inlet's transverse diameter. However, given the small cephalopelvic proportions among gorillas, an obstetric basis for dimorphism in relative sacral breadth appears unlikely. This raises the possibility that sacral dimorphism in gorillas is attributable to selection for relatively narrow sacra in males rather than relatively broad sacra in females. Accordingly, these results have implications for interpreting pelvic dimorphism among fossil primates, including hominins. Am J Phys Anthropol 152:435–446, 2013. © 2013 Wiley Periodicals, Inc.     

Differences among primates in defence against infection: sensitivity of polymorphonuclear leukocytes to fMet-Leu-Phe

The sensitivity of polymorphonuclear leukocytes (PMN) to N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe) for chemotaxis and for lysosomal enzyme release was examined using the PMN of four primate species, human (H. sapiens), chimpanzee (P. troglodytes), rhesus monkey (M. mulatta), and cotton-headed tamarin (S. (O) oedipus). The 50 per cent effective concentrations (EC50) of fMet-Leu-Phe for chemotaxis were 2.5 X 10(-9) M in human, 10(-9) M in chimpanzee, 8 X 10(-8) M in rhesus monkey, and 3.3 X 10(-6) M in tamarin. The EC50 values of fMet-Leu-Phe for myeloperoxidase (MPO) release were 10(-8) M in human, 4 X 10(-8) M in chimpanzee, 4 X 10(-8) M in rhesus monkey, and 10(-6) M in tamarin and those for beta-glucuronidase release were 4 X 10(-9) M, 6.4 X 10(-8) M, 1.8 X 10(-7) M, and 1.6 X 10(-6) M, respectively. Thus, the sensitivity to fMet-Leu-Phe for chemotaxis was in the order: chimpanzee congruent to human greater than rhesus monkey greater than tamarin, and that for the release of lysosomal enzymes, MPO and beta-glucuronidase, was in the order: human greater than chimpanzee greater than rhesus monkey greater than tamarin. These results appear to indicate that the sensitivity to fMet-Leu-Phe increases in the order of evolution of primates toward the human, and suggest that the sensitivity of PMN in the defence function against infection also increases in the same order.     

Geophagy among primates: adaptive significance and ecological consequences

We review geophagy, or soil ingestion, in primates. This behaviour is widespread and is presumed to be important to health and nutrition. Primates may engage in geophagy for one or a combination of reasons. Here we present, and make a preliminary assessment of, six nonexclusive hypotheses that may contribute to the prevalence of geophagy. Four hypotheses relate to geophagy in alleviating gastrointestinal disorders or upsets: (1) soils adsorb toxins such as phenolics and secondary metabolites; (2) soil ingestion has an antacid action and adjusts the gut pH; (3) soils act as an antidiarrhoeal agent; and (4) soils counteract the effects of endoparasites. Two hypotheses pertain to geophagy in supplementing minerals and/or elements: (5) soils supplement nutrient-poor diets and (6) soils provide extra iron at high altitudes. In addition to these hypotheses, geophagy may satiate olfactory senses, serve as a famine food and finally may have no function at all. We draw together a large body of information from various sources to assess these hypotheses and suggest some tests to understand the function of geophagy. Our review suggests that primates engage in geophagy for a number of reasons that are nonexclusive. We conclude that mineral supplementation, adsorption of toxins, treatment of diarrhoea and pH adjustment of the gut seem the most plausible reasons why primates engage in geophagy. Copyright 2000 The Association for the Study of Animal Behaviour.     

Comparison of object manipulation among 74 species of non-human primates

Seventy-four primates species (24 genera of six families) were presented with a nylon rope and a wooden cube, and their subsequent manipulations were recorded in detail. Five hundreds and six manipulation patterns were distinguished on the basis of the actions performed, body-parts used and relations to other objects. Inter-specific comparisons revealed three groups: (1) lemurs, marmosets, spider monkeys and leaf-eaters; (2) Old World monkeys except leaf-eaters; and (3) cebus monkeys and apes. The first group had the smallest repertoire of manipulations, in which only a few types of actions and body-parts were involved. The second and third groups had more varied modes of manipulation. Actions such as Roll, Rub and Slide, and use of fingers characterized these groups. Except for the lesser ape, their manipulations were frequently related with other objects. Moreover, actions such as Drape, Drop, Strike, Swing and Throw were typical of the third group. The factors producing such inter-specific differences in manipulations and the relations to tool use are discussed.     

Testing mechanisms of coexistence among two species of frugivorous primates

1. We examined mechanisms of coexistence between two congeneric species of frugivorous primates, the blue monkey (Cercopithecus mitis) and the red-tailed monkey (C. ascanius). 2. We used giving-up densities (the amount of food which animals leave in a patch) in fruit trees to measure foraging efficiency and to evaluate possible mechanisms of coexistence. Animals with higher giving-up densities are less likely to persist in the company of those with lower giving-up densities because the former are not able to exploit food patches used previously by the latter. We climbed trees to estimate giving-up densities by counting the fruit which primates left behind. 3. We tested five possible mechanisms of coexistence. Three mechanisms proposed that each frugivorous species has a lower giving-up density than the other in at least one of the following: (1) different tree species, (2) within-tree foraging zones or (3) seasons. The fourth mechanism predicted that the socially dominant species exploits resources first and that the subordinate species has lower giving-up densities. The final mechanism predicted that one species would find resources more quickly than the other, which would in turn have a lower giving-up density. 4. Four of the five mechanisms received no support from our data. Only a trade-off between interspecific dominance and giving-up densities was supported. 5. We discuss the generality of our results and possible interactions with other factors.     

旅游干扰对非人灵长类动物的影响

随着经济发展及生活水平的提高,以亲近自然为主要目的的生态旅游正成为公众的主要休闲方式.作为人类的近亲,非人灵长类动物在吸引游客方面具有天然的亲和力,因此很多保护区及旅游景区正逐渐把“猴园”、“猴谷”及“猴岛”等作为招揽游客的平台.野外观猴能够提高公众的野生动物保护意识,但同时也给动物带来了负面影响.该文综述旅游活动对动物行为模式、繁殖和健康状况等的影响,并对减少不利影响的措施进行归纳总结,为开展非人灵长类动物观赏旅游提供参考.