Leptin, adiposity, and testosterone in captive male macaques

Leptin is considered to act as a signal relating somatic energetic status to the reproductive system. However, the nature of that signal and its relationship with male reproductive function across nonhuman primate species are unclear. We suggest that species-specific differences in leptin physiology may be related to the degree of environmental variation and variation in the importance of energy stores for male reproduction. In order to test the role of seasonality in species differences among nonhuman primates, we compared leptin, testosterone, and body composition in male rhesus (n = 69) and pig-tailed (n = 43) macaques. Despite having larger abdominal fat deposits, the rhesus macaques did not exhibit significantly higher leptin levels (rhesus, 2.21 +/- 0.43 ng/ml; pig-tailed, 2.12 +/- 0.39 ng/ml). Both species showed increases in leptin across adolescent, subadult, and adult age-groups (P = 0.036 for rhesus; P = 0.0003 for pig-tailed by ANCOVA). Testosterone was not significantly associated with leptin in either the rhesus (r = 0.039; P = 0.754) or pig-tailed (r = 0.2862; P = 0.066) samples. Comparison of leptin levels across the two species using univariate modeling procedures showed no significant age-group by abdominal fat interaction. These findings suggest little difference in leptin production between these two closely related species, despite the difference in breeding seasonality.     

Sympatry between white-handed gibbons (Hylobates lar) and pileated gibbons (H. pileatus) in Southeastern Thailand

White-handed gibbons (Hylobates lar) are not known to occur to the east or southeast of Bangkok. The reliably documented localities ofH. lar nearest to this area are about 120 km northeast of Bangkok. There, in the Kao Yai National Park, is the only known zone of contact betweenH. lar and the pileated gibbon (H. pileatus), another species of the so-calledlar group. Unpublished documents dating from 1925 indicate, however, that sympatry between these two species may also have existed in the region of Sriracha, about 80 km southeast of Bangkok. Therefore, a large zone of overlap in the distribution of the two species may originally have existed. In most parts of this hypothetical zone, gibbon habitat appears to have been destroyed, with the Khao Yai Park possibly representing the last remnant of the once large contact zone.     

Group harmony in gibbons: Comparison between white-handed gibbon (Hylobates lar) and siamang (H. syndactylus)

The siamang (Hylobates syndactylus) is exceptional among gibbons in that its area of distribution almost completely overlaps those of other gibbons, namely the white-handed gibbon (H. lar) and the agile gibbon (H. agilis) of the lar group. The siamang has almost twice the body weight of the gibbons of the lar group (ca. 11 kg vs. 5–6 kg), and it has been suggested that distinct ecological and behavioural differences exist between the siamang and its two sympatric species. The siamang has been claimed to differ from the white-handed gibbon “in the closer integration and greater harmony of group life” (Chivers, 1976, p. 132). However, few quantitative data exist to support this hypothesis. In the present study, intra-group interactions in captive family groups of white-handed gibbons and siamangs (two groups of each species) were recorded by focal-animal sampling. These data failed to show a consistent association between species and most of the behavioural patterns recorded, such as frequency of aggression, percentage of successful food transfer, frequency of social grooming bouts, and duration of social grooming/animal/hr. A significant difference was found for only two of the variables: Individual siamangs in this study showed longer grooming bout durations, and made fewer food transfer attempts than lar individuals. Only the first of these two differences is consistent with the hypothesis mentioned above, whereas the lower frequency of food transfer attempts in siamangs is the opposite of what should be expected under the hypothesis. On the other hand, two of these behavioural patterns showed a significant correlation with the parameters group size and individual age: Both individuals in larger groups and younger individuals tended to show shorter grooming bouts and a smaller proportion of successful food transfers. Our findings indicate that social cohesion within these gibbon groups may be much more flexible according to and depending on social or ecological influences and less rigidly linked to specific gibbon taxa than previously assumed. A considerably larger number of gibbon groups would have to be compared to provide reliable evidence for or against species-specific differences in group cohesion. Another finding of this study—a positive correlation between the frequency of aggression and grooming—is discussed in the light of the functional interpretations commonly attributed to allogrooming behaviour in primates.     

Behavioral contrasts between male cynomolgus and lion-tailed macaques

Evidence indicates that primate species differ not only in social structure and concordant social propensities, but also in their approach toward novel objects, environments, and procedures. These differences in response dispositions have been described as being based on differences in characteristic stances toward the environment, also called temperaments. This report extends previous comparative primate research by describing behavioral contrasts observed among males of two macaque species, liontailed and cynomolgus macaques. The lion-tails demonstrated more interest in other animals, more vigilance and instrumental behavior, and more readily adapted to training to enter a small and unfamilar cage than the cynomolgus. These results suggest temperamental differences between the two species. Lion-tails may be characterized as bold, curious, and instrumental in their approach to the environment, while cynomolgus may be characterized as more passive or “reserved”. These differences may form the basis for the well-developed sensorimotor abilities observed in liontails such as the manufacture and use of tools, and may also be related to their highly omnivorous diet. © 1993 Wiley-Liss, Inc.     

云南白马雪山自然保护区猕猴和滇金丝猴的生态位分离(英文)

原则上,食叶的滇金丝猴(Rhinopithecus bieti)和杂食的猕猴(Macaca mulatta)是可以同地共栖的,但这两种灵长类究竟是如何同地共存却一直是一个鲜见涉足的问题。该文初步通过分析它们的食性和生境需求来阐明两者共存的可能性。在猕猴取食约22种植物中,有16种也是滇金丝猴的取食对象。两种灵长类都显示出喜食果实。人们尚未发现滇金丝猴涉足人类作物等相关资源,但发现猕猴经常侵食庄稼。这与其生活海拔不同有关:滇金丝猴一般生活在平均海拔为3218m的山林中,而猕猴活动在平均海拔为2995m的林地。猕猴也会涉足牧场,而滇金丝猴回避这种场地。对于这两个种,混合的落叶阔叶/针叶林是最频繁使用的森林类型;滇金丝猴很少进入常绿阔叶林(青冈属群落,利用率仅3%),而猕猴相对进入这类林型的机会远比滇金丝猴高(36%)。两个物种的群体间常相互远离(2.4km)。当其相遇时,常是猕猴主动回避。上述结果提示滇金丝猴和猕猴是通过大生境分化利用和空间避让来共存的。尽管不同的生境利用策略一定程度上会反映种间竞争的存在,但这种不同更可能反映着它们不同的生理/生态需求。     

Social factors modulate the effects of hormones on the sexual and aggressive behavior of macaques

We previously reviewed the effects of gonadal hormones on the sexual and aggressive behavior of macaques as observed in field, outdoor colony, and laboratory studies. There were consistent similarities between findings from different observational settings, but there were also noteworthy differences which suggested the importance of social and environmental factors in modulating the effects of hormones. We now examine the role of these factors further and consider the extent to which partner preferences, familiarity between individuals, and also dominance rank can affect the behavior of male-female pairs and thereby modify the influences of hormones. The evidence suggests that all these factors are important. Hormone-dependent short-term partner preferences appear to be critical for the formation of consort bonds and to facilitate mating between unfamiliar partners. Socially based partner preferences tend to dampen hormonal influences and may lead to long-term familiarity. Long-term familiarity decreases sexual interactions and may be a proximate mechanism underlying incest avoidance and periodic male troop transfers. Both males and females exhibit mate competition under certain conditions, and their dominance rank can modify sexual and aggressive behavior by either optimizing or reducing hormone-dependent changes. These interaction effects between social and hormonal variables also have relevance for the design and interpretation of laboratory experiments. © 1996 Wiley-Liss, Inc.     

Interactions between visitors and Formosan macaques (Macaca cyclopis) at Shou‐Shan Nature Park,Taiwan

Ecotourism involving feeding wildlife has raised public attention and is a controversial issue, especially concerning nonhuman primates. Between July 2002 and April 2005, the behavior of monkeys and tourists was collected through scan samplings, focal samplings and behavior samplings at the Shou‐Shan Nature Park located in Taiwan's second largest city—Kaohsiung. In addition, the number of tourists and monkeys was counted in different hours and places within the park. Four hundred visitors were interviewed using a questionnaire to gather data on sex, age, purpose and frequency of visit to the park. The number of tourists was significantly higher during weekends than in weekdays in all locations. Humans dominated in the initiation of interspecies interactions—the overall ratio of human‐initiated and monkey‐initiated interactions was 2.44:1. Human–monkey conflicts accounted for only 16.4% of the total interactions (n=2,166), and adult human males and adult male macaques participated in higher rates than other age/sex groups in these conflicts. Visitors showed more affiliative behavior (15.9%) than agonistic behavior (8%) toward the macaques. In response to visitors' threat or attack, the Formosan macaques mostly showed submissive behavior with bared teeth, squealed or ran away to avoid confrontation (69.1%)—only few responded with counteraggression (18.7%). This study for the first time provided evidence that food provisioning increased both the frequency and duration of aggression among Formosan macaques (P<0.001). During food provisioning, the average frequency and the duration of agonistic events of macaques were more than 4 times higher compared with those without food provisioning. The average frequency of food provision by tourists was 0.73 times/hr—more than twice the incident that monkeys grabbed the food from tourists (0.34 times/hr). If people refrain from feeding monkeys and destroying the city park's natural vegetation, monkeys can be used to educate public about nature conservation in an urban setting. Am. J. Primatol. 71:214–222, 2009. © 2008 Wiley‐Liss, Inc.     

Inter-annual variation of reproductive parameters and fruit availability in two populations of Japanese macaques

Among wild Japanese macaques, which have clear reproductive seasonality, correspondence between fruit-food production in the mating season and birth rate in the following year was confirmed in two different habitats. One of the study areas was evergreen broad leaved forest on Yakushima Island, for which demographic and fruiting data for seven years were used. The other was a deciduous-coniferous mixed forest on Kinkazan Island in the cool temperate zone, for which 11 years of data were used. From the fruit-crop data, each year was classified as a good or bad fruiting year for each population. At both habitats, female macaques had fewer babies after bad fruiting years than after good fruiting years. In Yakushima, small troops had a lower birth rate than large troops and this tendency was clear after bad fruiting but not after good fruiting. On the other hand, in Kinkazan such differences due to troop size were not found. These findings were consistent with the observation that intertroop encounters occur more often and are more agonistic in Yakushima than in Kinkazan and large troops tend to be dominant to small troops in the Yakushima population. Thus annual fluctuations in fruit production appear to increase the difference in birth rates between troops of different sizes through intertroop competition in Yakushima, but not in Kinkazan.     

Resisting annihilation: relationships between functional trait dissimilarity,assemblage competitive power and allelopathy

Allelopathic species can alter biodiversity. Using simulated assemblages that are characterised by neutrality, lumpy coexistence and intransitivity, we explore relationships between within‐assemblage competitive dissimilarities and resistance to allelopathic species. An emergent behaviour from our models is that assemblages are more resistant to allelopathy when members strongly compete exploitatively (high competitive power). We found that neutral assemblages were the most vulnerable to allelopathic species, followed by lumpy and then by intransitive assemblages. We find support for our modeling in real‐world time‐series data from eight lakes of varied morphometry and trophic state. Our analysis of this data shows that a lake's history of allelopathic phytoplankton species biovolume density and dominance is related to the number of species clusters occurring in the plankton assemblages of those lakes, an emergent trend similar to that of our modeling. We suggest that an assemblage's competitive power determines its allelopathy resistance.     

Relation between the dominance rank of female rhesus monkeys and their access to males

Systematic observations were made on 12 measures of the sexual, aggressive, and social interactions of 24 male–female pairs of rhesus monkeys in six social groups, each consisting of one male and four ovariectomized females tested in a large room. Each female in a group was treated in turn first with estradiol alone and then with estradiol and progesterone in combination. When hormone-treated, the female was also observed during pair tests with the male in the same large observation room (four males, eight females, 240 group tests, 240 pair tests). The dominance ranks of females during group tests were determined post hoc by means of the dominance index [Zumpe & Michael, American Journal of Primatology 10:291–300, 1986]. In all six groups, the most dominant female virtually monopolized the male, and the subordinate females' interactions with the male, assessed during pair tests, were almost completely suppressed during group tests. This “dominant female effect” was a robust phenomenon that depended solely on female dominance rank. It was independent of the identity and hormonal status of females and of the social preferences of males as expressed in pair tests. These findings demonstrate the existence of female mate competition in an Old World primate.     

When carnivores collide: a review of studies exploring the competitive interactions between bobcats Lynx rufus and coyotes Canis latrans

1. Bobcats Lynx rufus and coyotes Canis latrans are two widespread mesopredators with a complex history of sympatry. The competitive interactions between these species are of interest to biologists due to the furbearer status of bobcats, the recent range expansion of coyotes, and the recolonisation of several parts of North America by bobcats following their extirpation. Although studies exploring the dynamics and competition between bobcats and coyotes span decades, there is a lack of understanding regarding what factors influence exploitative or interference competition, and what methodologies are conducive to identifying these types of competition.
2. We gathered a comprehensive list of research papers (n = 41) exploring bobcat–coyote competitive interactions in North America. From them, we collected the following: study site characteristics, number and types of research methods, number and types of metrics explored, history of sympatry of the two species at the study location, presence of apex predators, and documentation of interference and/or exploitative competition.
3. Using generalised linear models, we determined that interference competition between bobcats and coyotes was observed primarily in open habitat. However, habitat heterogeneity, the number of research methods and metrics used, presence of an apex predator, and history of sympatry could not be used to predict the occurrence of interference competition. Studies that included diet overlap were less likely to observe interference competition than studies that used other metrics to infer competition.
4. Competitive interactions between coyotes and bobcats are largely a function of prey availability. Our findings suggest that habitat type may be a surrogate for prey availability, which many researchers mention, but do not explicitly measure. Future studies investigating bobcat–coyote interactions should include the quantification of prey densities to gain a more comprehensive understanding of the system at large, and should avoid using solely diet or habitat overlap as metrics to assess competition.

     

海南南湾猴岛景区内猕猴与游客接触行为的研究

在世界范围内,观赏和投喂野生猿猴是最常见的野生动物旅游形式之一。其中游客与动物的关系越来越成为动物学、人类学和社会学学者研究关注的热点。游客在娱乐的过程中,存在被猿猴威胁甚至咬伤等问题。对人猴接触行为的客观分析,是提高旅游服务管理和保障游客安全的必要措施。本研究记录了2012-2014年海南南湾猴岛景区内游客与猕猴的接触行为,并分析了景区医务室近两年的游客就诊记录,主要探讨：（1）哪些游客会参与人猴接触,及其游客的认识误区;（2）哪些猕猴会频繁参与人猴接触;（3）哪些原因会引发人猴接触行为。本文旨在了解景区内游客与猿猴的互动关系,探讨游客受伤原因及其解决办法,为完善野生动物旅游的健康发展提供基础资料。     

Relationship between sexual interactions and the timing of the fertile phase in captive female Japanese macaques (Macaca fuscata)

Japanese macaques live in multi‐male/multi‐female social groups in which competition between males, female mate choice, and alternative male mating strategies are important determinants of mating and reproductive success. However, the extent to which adult males rely on female behavior to make their mating decisions as well as the effect of social rank on mating success are not clear as results are inconclusive, varying from study to study. In this study, we combined behavioral and endocrine data of 14 female Japanese macaques to examine the relationship between ovarian cycle phase and frequency of sexual behaviors, and to investigate how social rank influences sexual behavior in this species. We found that there was no increase in female proceptive behaviors during the fertile phase of the ovarian cycle, suggesting that female behaviors did not clearly signal the probability of conception. In spite of that, the frequencies of ejaculatory copulations were highest during this phase, indicating that the attractivity of females increased significantly during the period with higher probability of conception. Males, and especially the highest ranking male, were able to discriminate females nearing ovulation and to concentrate their mating effort, implying that the timing of ovulation was not concealed from them. The α male seemed able to monopolize most female matings, which is probably due in part to the low number of females simultaneously ovulating and to the limited number of inconspicuous places that the lower ranking males have to mate with females and avoid α male aggression. All together, these results suggest that different males may have access to different signals of ovulation and/or are differentially restrained as to how they can act on that information. The exact nature of the estrogen‐related cues males use to recognize female reproductive status, and to what extent males use them warrants further investigation. Am. J. Primatol. 71:868–879, 2009. © 2009 Wiley‐Liss, Inc.     

野生雄性黄山短尾猴性行为季节性变化同步性(英文)

季节性繁殖是非人灵长类动物的普遍特征,而野生雄性个体的性行为季节性变化特点仍有待研究。该研究于2005年10月至2006年9月对黄山短尾猴鱼鳞坑YA2群5只成年雄性个体进行全年观察,以期探讨雄性黄山短尾猴性行为季节性变化特征。结果表明:繁殖季节交配行为和性动机行为(性追赶,做鬼脸和性检查)频次显著高于非繁殖季节,季节性差异显著。成年雄性个体交配行为和性动机行为季节性变化呈现显著同步性。该研究为进一步阐明短尾猴和同属季节性繁殖非人灵长类动物的雄性竞争和雄性策略提供理论依据。     

Disproportionate participation by age/sex classes in aggressive interactions between long-tailed macaques (Macaca fascicularis) and human tourists at Padangtegal monkey forest, Bali, Indonesia

We observed 420 aggressive interactions between tourists and Macaca fascicularis at the Padangtegal Wanara Wana Temple forest site in Bali, Indonesia, during the months of June and July 2001. The data collected included patterns of aggression, presence or absence of food, and demographic information on resident macaques and human visitors. Analyses of the interactions suggest that macaques respond differentially to humans according to the age/sex classes involved. Additionally, adult and subadult male macaques participated in more aggressive behaviors than expected, while adult female macaques and immatures participated in such behaviors less than expected. These variations in interaction patterns between macaques and tourists may have substantial implications for management issues and the potential for pathogen transmission.     

Interactions within and between species at different densities of the bark beetleIps typographus and its predatorThanasimus formicarius

Interactions between the bark beetleIps typographus and one of its predators,Thanasimus formicarius, were investigated in caged spruce logs containing both species in eight different density combinations. Productively (offspring per female) ofIps was adversely affected by highIps gallery density as well as highThanasimus density.Thanasimus productivity was enhanced by highIps gallery density but negatively affected by highThanasimus density.Ips productivity andThanasimus developmental rate differed between tree individuals, probably owing to tree-related differences in phloem thickness. Relative predator-causedIps mortality was ca 20% higher at high gallery density (ca 300 egg galeries per m²) than at low gallery density (ca 100 egg galleries per m²), indicating that mortality was density dependent. This difference was due to the fact thatThanasimus larval density was positively related toIps gallery density. Mortality increased by ca 0.4% with each additionalThanasimus larva per m², independently of gallery density. Relative population levels ofIps andThanasimus were monitored with pheromone traps in two regions differing in theirIps typographus outbreak history. Absolute catch as well as theThanasimus/Ips catch ratio were ten times greater in the outbreak region than in the non-outbreak region. Coupled with the results in the caging experiment, this indicates thatT. formicarius responds numerically to changes inI. typographus numbers per unit bark area as well as toIps population changes at the regional level. The findings suggest that predation under bark may be a significant factor in supressingI. typographus outbreaks.