The Ecology and Evolution of Hylobatid Communities: Causal and Contextual Factors Underlying Inter- and Intraspecific Variation

Malone, Nicholas; Fuentes, Agustín

doi:10.1007/978-0-387-88604-6_12

Cited by 21 publications

(14 citation statements)

References 44 publications

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“…H. muelleri , the gibbon species with the lowest number of amygdala neurons in this analysis (Fig. 5), has not been observed traveling in larger groups (Malone and Fuentes, 2009). Thus, it is possible that neuroanatomical variation in our sample might reflect behavioral variation among gibbon species, given that social group size has been shown to correlate with amygdala volume (Barton and Aggleton, 2000; Bickart et al, 2010).…”

Section: Discussionmentioning

confidence: 67%

“…An important feature of our gibbon sample is that it represented three distinct species. Traditionally, the social organization of all gibbon species was thought to be the monogamous pair bond; more recent data have challenged this presumption (Malone and Fuentes, 2009). In our study, the two gibbons with the highest numbers of amygdala neurons (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Neuronal populations in the basolateral nuclei of the amygdala are differentially increased in humans compared with apes: A stereological study

Barger

Stefanacci

Schumann

et al. 2012

J of Comparative Neurology

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In human and nonhuman primates, the amygdala is known to play critical roles in emotional and social behavior. Anatomically, individual amygdaloid nuclei are connected with many neural systems that are either differentially expanded or conserved over the course of primate evolution. To address amygdala evolution in humans and our closest living relatives, the apes, we used design‐based stereological methods to obtain neuron counts for the amygdala and each of four major amygdaloid nuclei (the lateral, basal, accessory basal, and central nuclei) in humans, all great ape species, lesser apes, and one monkey species. Our goal was to determine whether there were significant differences in the number or percent of neurons distributed to individual nuclei among species. Additionally, regression analyses were performed on independent contrast data to determine whether any individual species deviated from allometric trends. There were two major findings. In humans, the lateral nucleus contained the highest number of neurons in the amygdala, whereas in apes the basal nucleus contained the highest number of neurons. Additionally, the human lateral nucleus contained 59% more neurons than predicted by allometric regressions on nonhuman primate data. Based on the largest sample ever analyzed in a comparative study of the hominoid amygdala, our findings suggest that an emphasis on the lateral nucleus is the main characteristic of amygdala specialization over the course of human evolution. J. Comp. Neurol. 520:3035–3054, 2012. © 2012 Wiley Periodicals, Inc.

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Section: Discussionmentioning

confidence: 67%

Section: Discussionmentioning

confidence: 99%

Neuronal populations in the basolateral nuclei of the amygdala are differentially increased in humans compared with apes: A stereological study

Barger

Stefanacci

Schumann

et al. 2012

J of Comparative Neurology

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“…Western black crested gibbons are different from other gibbon species, not only due to their use of high-altitude (Bleisch & Chen 1991), harsh habitats (Fan et al 2009), and larger home range areas (Fan & Jiang 2008), but also due to the coexistence of monogynous and polygynous (Jiang et al 1999;Malone & Fuentes 2009) group structures. Among the western black crested gibbons at Wuliang Mountain, possible explanations for polygyny include large home ranges, mutual tolerance between females and selection pressure favoring polygyny (Jiang et al 1994(Jiang et al , 1999Fan & Jiang 2010).…”

Section: Complex Mating Systemmentioning

confidence: 99%

Observation of intra‐group and extra‐group copulation and reproductive characters in free ranging groups of western black crested gibbon (Nomascus concolor jingdongensis)

Huang

Guan

et al. 2013

Integrative Zoology

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Black crested gibbons (Nomascus concolor) are 1 of only 3 gibbon species that have been observed in long-term polygynous groups, but their mating behavior and reproductive characters have never been reported. Based on population monitoring over 7 years and direct observation for 26 months of the study groups in Wuliang Mountain, central Yunnan, we describe for the first time the copulation behavior and breeding pattern of free-ranging western black crested gibbons. The gestation period of black crested gibbons is estimated to be between 6 and 7 months. The average breeding interval is 3.5 years, with infant independence at approximately 2.5 years. We observed 2 intra-group copulations and 5 extra-group copulations. Copulations were initiated when a female gave a 'solicitation' gesture. When a male made any mating attempt, the female might refuse it. These results demonstrate direct female mate choice. Both male and female gibbons dispersed from their natal groups and sometimes replaced paired adults in other groups. We observed no evidence of infanticide during inter-group conflicts or after replacement of adults. Together with extra-group copulations, these phenomena indicate a flexible social organization and complex mating system. We also observed a male-biased sex ratio among offspring. More genetic work is necessary to describe the effects of inter-group copulation and the genetic diversity of this population.

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“…Crested gibbons, which comprise the genus Nomascus , are capable of inhabiting somewhat higher elevations than other species of gibbons [Malone and Fuentes, 2009]. As a consequence of these habitat differences, crested gibbons may need to depend on less rich food resources at times, with leaves comprising a seasonally important component of their diet [Bleisch and Chen, 1991].…”

Section: Discussionmentioning

confidence: 99%

“…Hylobates and Symphalangus are better studied, and their ecology and life histories are better understood than those of Nomascus (for an overview, see Malone and Fuentes [2009]). It is possible that lack of data on Nomascus may limit our ability to draw appropriate conclusions regarding patterns of sex ratio bias and its implications.…”

Section: Discussionmentioning

confidence: 99%

Sex Ratio Bias in Managed Populations of Hylobatids

Margulis

Burns²,

Rothenberg³

2012

IJFP

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A number of explanations have been proposed for the occurrence of sex ratio bias in primates, including the Trivers-Willard hypothesis on differential investment, local resource competition or enhancement as a result of sex-biased dispersal, dominance-related advantages conferred on one sex but not the other, and the fragile male hypothesis. However, none of these theories was thought to be applicable to monogamous primate species. Here, we examine data on zoo-housed populations of three hylobatid species to test the null hypothesis of equal sex ratio. We analyzed over 40 years of demographic data on Nomascus leucogenys, Hylobates lar and Symphalangus syndactylus. We identified a strong male-biased birth sex ratio in N. leucogenys. Male infant mortality was consistently higher than female infant mortality for N. leucogenys, but this difference was not significant. We found that prime-age N. leucogenys females (aged 13–20) produced significantly more male offspring than female offspring, and young S. syndactylus females (<13 years) produced significantly more female offspring. Recent field evidence of more flexible mating systems in H. lar and S. syndactylus may also be occurring in N. leucogenys. However, N. leucogenys has not been well studied in the wild. Ecological differences among species may further contribute to these observed patterns.

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The Ecology and Evolution of Hylobatid Communities: Causal and Contextual Factors Underlying Inter- and Intraspecific Variation

Cited by 21 publications

References 44 publications

Neuronal populations in the basolateral nuclei of the amygdala are differentially increased in humans compared with apes: A stereological study

Neuronal populations in the basolateral nuclei of the amygdala are differentially increased in humans compared with apes: A stereological study

Observation of intra‐group and extra‐group copulation and reproductive characters in free ranging groups of western black crested gibbon (Nomascus concolor jingdongensis)

Sex Ratio Bias in Managed Populations of Hylobatids

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