首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
《Hormones and behavior》2009,55(5):613-619
In group-living animals relative rank positions are often associated with differences in glucocorticoid output. During phases of social stability, when dominance positions are clear and unchallenged, subordinates often face higher costs in terms of social stress than dominant individuals. In this study we test this prediction and examine additional potential correlates of stress, such as reproductive season, age and amount of aggression received in wild, seasonally breeding Assamese macaques (Macaca assamensis). During a mating and a non-mating season we collected 394 h of focal observational data and 440 fecal samples of six adult and six large subadult males living in a multimale–multifemale group in their natural habitat in northeastern Thailand. The mating season was characterized by a general increase in aggressive behavior and glucocorticoid excretion across all males compared to the non-mating season. Among adult males, mating season glucocorticoid levels were significantly negatively related with dominance rank and positively with the amount of aggression received. Both relationships were non-significant among large subadult males. Thus, our results suggest that in adult Assamese macaques a high dominance position is not associated with high costs. Low costs of dominance might be induced by strong social bonds among top-ranking males, which exchange frequent affiliative interactions and serve as allies in coalitionary aggression against potentially rank-challenging subordinate males.  相似文献   

2.
In group-living animals relative rank positions are often associated with differences in glucocorticoid output. During phases of social stability, when dominance positions are clear and unchallenged, subordinates often face higher costs in terms of social stress than dominant individuals. In this study we test this prediction and examine additional potential correlates of stress, such as reproductive season, age and amount of aggression received in wild, seasonally breeding Assamese macaques (Macaca assamensis). During a mating and a non-mating season we collected 394 h of focal observational data and 440 fecal samples of six adult and six large subadult males living in a multimale–multifemale group in their natural habitat in northeastern Thailand. The mating season was characterized by a general increase in aggressive behavior and glucocorticoid excretion across all males compared to the non-mating season. Among adult males, mating season glucocorticoid levels were significantly negatively related with dominance rank and positively with the amount of aggression received. Both relationships were non-significant among large subadult males. Thus, our results suggest that in adult Assamese macaques a high dominance position is not associated with high costs. Low costs of dominance might be induced by strong social bonds among top-ranking males, which exchange frequent affiliative interactions and serve as allies in coalitionary aggression against potentially rank-challenging subordinate males.  相似文献   

3.
临时配偶关系指多雌多雄灵长类群体中的一只成年雄性连续跟随一只成年发情期/性接受期的雌性形成的异性关系,在季节性繁殖物种的交配季节表现的尤为明显,是雄性个体提高交配成功的策略之一。为了探讨能量消耗对这种行为的约束,本研究于2017年8月至2018年1月,以栖息于安徽黄山的短尾猴鱼鳞坑A1群(YA1群)的8~10只成年雄性为研究对象,采用目标动物取样法、行为取样法以及全事件记录法采集成年雄性自然发生的行为数据。通过分析移动时间、觅食时间和交配频次等行为指标,同时测定作为个体能量状态生理指标的尿液C-肽浓度(Urinary C-peptide , UCP),从行为和生理两个方面研究雄性短尾猴维持临时配偶关系的适应性特征。研究期间,在临时配偶期内,雄性的移动时间无显著变化,但觅食时间和交配频率显著增加;在临时配偶期内,当存在雄性竞争者时,雄性的觅食时间显著减少;临时配偶关系对雄性的UCP水平无显著影响。结果表明,雄性短尾猴在临时配偶期内可能会根据能量消耗的情况以及守护雌性周围的社会环境对自身行为进行调整,以减少其在临时配偶期内的能量投资,提高自身维持临时配偶关系的行为适应性。  相似文献   

4.
Abstract Antipredator mechanisms employed by animals are obviously beneficial if they increase survival, but their use may be costly and decrease fitness. Fitness costs of antipredator mechanisms may, in turn, be defrayed by behavioural compensation. We used lizards as a model to measure behavioural fitness costs of the antipredator mechanism, autotomy, as they commonly lose their tails when attacked by predators. In addition, we examined whether male skinks, Carlia jarnoldae (Scincidae), behaviourally compensate for tail loss by comparing the behaviour of tailed and tailless males in experimental enclosures, either alone, with a conspecific male or female, or with a predator. Tailless males experience several costs of autotomy including reduced energy stores, and loss of autotomy as a defence. We identified an additional cost of tail loss: reduced mating success. However, this species did not behaviourally compensate these costs. Instead, characteristics of the ecology of C. jarnoldae may minimize the costs of autotomy. This species experiences an extended breeding season, which means that they experience reduced mating success for only 20% of this breeding season. Additionally, the presence of inguinal fat stores which supply energy in addition to stores in the tail reduce energetic costs.  相似文献   

5.
Costs of mating effort can affect the reproductive strategies and lifetime fitness of male primates, but interspecific and interindividual variation in the magnitude and distribution of costs is poorly understood. Male costs have primarily been recognized in seasonally breeding species that experience concentrated periods of mating competition. Here, we examine foraging costs associated with male mating effort in chimpanzees (Pan troglodytes schweinfurthii), a polygynandrous species, in which mating opportunities occur intermittently throughout the year. To quantify male feeding, aggression, and mating, we conducted focal follows on 12 males in a wild community (Kanyawara, Kibale National Park, Uganda) for 11 mo. Males fed less on days when high-value mating opportunities (estrous parous females) were available than on days without any mating opportunities. Reductions in feeding time were related to increased rates of aggression and copulation, indicating that the proximate cause of changes in male foraging was mating effort. Surprisingly, however, there was no relationship between dominance rank and the extent to which feeding time was reduced. High costs of mating effort may reduce the degree of reproductive skew and limit the use of possessive tactics in chimpanzees. We suggest that male bonding in chimpanzees may be favored not only for its benefits but because intragroup competition is so costly. Our results complement the available data on mammals, and primates in particular, by showing that mating effort can have measurable foraging costs even in species, in which breeding is aseasonal and only moderately skewed.  相似文献   

6.
In contrast to most mammalian species, female sexual activity is not limited to the fertile phase of the ovarian cycle in anthropoid primates, which has long been proposed to conceal the timing of ovulation to males. It is now generally believed that females are still most attractive during the fertile phase, leading to high-ranking males successfully mate-guarding them specifically during this period. While studies conducted in species exhibiting exaggerated sexual swellings (probabilistic signal of the fertile phase) have generally supported this hypothesis, mixed support comes from others. Here, we investigated whether high-ranking males timed mate-guarding effort towards female fertile phases in rhesus macaques (Macaca mulatta). In this species, adult females do not exhibit sexual swellings, but undergo facial skin colour variation, an alternative oestrogen-dependent graded-signal of female reproductive status. We collected behavioural, hormonal and genetic paternity data during two mating seasons for one group of the free-ranging population of Cayo Santiago. Our results show that mate-guarding by top-ranking males did not completely cover the entire female fertile phase and that this tactic accounted for only 30-40% of all fertilisations observed. Males tended to prolong mate-guarding into the luteal phase (null probability of fertilisation), which mirrors the pattern of male attraction to female facial colour reported in an earlier study. These findings suggest that males may have limited knowledge regarding the exact timing of females' fertile phase in rhesus macaques, which presumably allows females to gain more control over reproduction relative to other anthropoid primate species.  相似文献   

7.
In many species interactions among group are often characterized by agonistic behaviour. Although animals may participate in inter‐group encounters in different ways, depending on their energetic requirements, reproductive tactics, and/or developmental stage, the proximate causes affecting an animal's participation in inter‐group encounters are still poorly understood. Indeed, many studies have analysed the behaviour of males and females during inter‐group encounters without considering the importance of additional factors (e.g. rank). This study focuses on wild non‐provisioned Japanese macaques (Macaca fuscata yakui) living on Yakushima Island, Japan. It aims to determine how monkeys of different sex, age, and rank behave during inter‐group encounters and it discusses the implications and consequences of their behaviour on group composition and male dispersal. Males participated significantly more than females in inter‐group encounters, by displaying more aggressive or affiliative behaviour. High‐ranking and/or adult males were more aggressive than low‐ranking and/or subadult males during encounters occurring in the mating season and they also showed more herding behaviour. This trend was not found in inter‐group encounters occurring during the non‐mating season. Finally, males which then emigrated to new groups were low‐ranking and/or subadult individuals. Those males displayed more affiliative behaviour towards foreign males than males which did emigrate. These data indicate that in non‐territorial species with male dominance over female and high competition for mating partners males play an active, and often aggressive, role during inter‐group encounter while female participation is scarce. Factors such as age, rank and period of the year (in seasonally breeding species) have to be taken into considerations when analysing interactions between groups and their effects on group composition and social behaviour.  相似文献   

8.
An extensive body of research exists on androgen secretion in males. Although androgens are also known to drive patterns of female reproductive physiology and behavior, little attention has been paid to these “male” hormones in females. Here, we examined female fecal androgen excretion in strictly seasonally breeding wild Assamese macaques (Macaca assamensis) and tested the hypothesis that changes in premating season fecal androgens vary with female readiness to resume ovarian cycling and thus to conceive. Across 2 years, 155 fecal samples were collected from seven reproductively quiescent (i.e., acyclic) females during the premating season months, August and September. Samples were analyzed for immunoreactive epiandrosterone (iEA), a major fecal metabolite of testosterone in macaques. Changes in iEA concentrations during the premating season were significantly negatively associated with (1) the presence of dependent offspring, i.e., lactating females showed a smaller change, and (2) with the timing of conceptions in the mating seasons, i.e., females that conceived early exhibited the greatest changes. These results provide strong evidence for a relationship between changes in androgens during the premating season and female readiness to conceive. Am J Phys Anthropol 151:311–315, 2013. © 2013 Wiley Periodicals, Inc.  相似文献   

9.
三种笼养灵长类活动时间分配的比较研究   总被引:1,自引:1,他引:1  
采用焦点动物法和连续记录法对3种笼养灵长类活动时间分配进行比较研究。结果表明,川金丝猴Rhi-nopithecus roxellanae和熊猴Macaca assamensis用于休息的时间多于猕猴Macaca mulatta,移动时间则相反;川金丝猴和猕猴用于理毛的时间多于熊猴。不同性别年龄组之间的活动时间分配有差异,主要表现在川金丝猴母亲用于理毛的时间明显多于成年儿子,用于玩耍的时间则相反;猕猴成年雄性的移动时间和理毛时间多于成年雌性,玩耍时间则少于成年雌性;熊猴成年雌性的移动时间多于成年雄性,与成年个体相比,幼体花更多的时间用于玩耍,而相应的减少了其休息时间。  相似文献   

10.
In numerous primates living in mixed-sex groups, females display probabilistic cues of fertility to simultaneously concentrate paternity to dominant males while diluting it amongst others as a means to reduce the risk of infanticide and to increase male care for offspring. A few species, however, lack these cues and potentially conceal fertility from males; yet, to date, little is known about mating patterns and their underlying proximate mechanisms in such species. Here, we investigated mating activity and sexual consortships relative to female reproductive state in wild Assamese macaques (Macaca assamensis), a species where females lack prominent anogenital swellings and copulation calls. During two mating seasons (2837 contact hours) we recorded sexual and social behaviors, sexual consortships, and collected 1178 fecal samples (n = 15 females) which were analyzed for progestogen concentrations to assess female reproductive state and to determine the timing of ovulation and conception. Although mostly conceiving in their first ovarian cycle, females were sexually receptive throughout the entire 4-month mating season, and within-cycle mating frequencies were not increased during fertile phases. Dominant males did not monopolize fertile matings, and consortships by high-ranking males lasted for long periods, which were not exclusively linked to female fertile phases. Furthermore, females copulated promiscuously but not randomly, i.e. for almost every female, matings were concentrated to a certain male, irrespective of male rank. Collectively, we demonstrate that fertility is undisclosed to males. The extreme extended female sexuality facilitated by concealed fertility may allow females to create differentiated mating relationships within a promiscuous mating system. Our study provides important new insight into the plasticity of female sexuality in non-human primates.  相似文献   

11.
The distributions of Assamese macaques (Macaca assamensis) and rhesus macaques (M. mulatta) in Bhutan have been only partially documented. In order to investigate the distribution patterns of these species, we conducted field observation and genetic assessment with mitochondrial DNA (mtDNA) typing of macaques in the Inner Himalayas of Bhutan. There were 24 sightings of macaque groups, and all were visually identified as Assamese macaques. No groups of rhesus macaques were sighted in this survey area, in contrast with the survey results in the Nepalese Himalayas. Molecular phylogenetic analysis revealed that the Bhutan macaques are closer in proximity to their counterparts in the Indo-Chinese region (Thailand and Laos) than to rhesus macaques in China, Laos and India. However, clustering results suggested the marked differentiation of the macaques in Bhutan from the Assamese macaques in Indo-China. We tentatively conclude that the macaques of the Inner Himalayan regions in Bhutan are Assamese macaques and that they appear to be of a lineage distinct from Assamese macaques in the Indo-Chinese region (subspecies M. a. assamensis). The degree of mtDNA diversity suggests that the Assamese macaques in Bhutan are of a more ancient ancestry than M. a. assamensis, thereby supporting the speciation hypothesis of the expansion of a sinica-group of macaques from South Asia to Southeast and then to East Asia (Fooden; Fieldiana Zool 45:1–44, 1988). Assignment of Assamese macaques in Bhutan to M. a. pelops is premature due to the lack of molecular data and recent taxonomic controversy. The mtDNA diversity of Assamese macaques was greater than that of rhesus macaques, suggesting the earlier speciation of Assamese macaques. The significance of the ecogeographic segregation model of macaque distribution is discussed in relation to the evolutionary range expansion into the Himalayan regions in South Asia.  相似文献   

12.
Sexual selection acts to increase the success of males possessing advantageous traits in competition over females. In primates, interspecific variability in social and mating systems creates highly variable selective pressures on males, changing the relative strength of both intra- and intersexual selection, and the relative degree of direct vs. indirect male–male competition. Rhesus macaques are an interesting species for studying intrasexual selection and male–male competition, because they exhibit relatively low (for Papionini) body and canine size dimorphism, and exhibit large testes, suggesting reduced direct competition and strong indirect competition. We have undertaken several studies of male rhesus macaques on Cayo Santiago, from analyses of long-term life-history data to shorter term projects that combined noninvasive measures of physiological markers such as concentrations of urinary C-peptide of insulin and androgen and glucocorticoid (GC) concentrations, with measures of behavior and of sexually selected signals (male red facial coloration). We here review these studies, combining data from short-term studies with long-term mortality data to present an integrated picture of both the short- and long-term gross costs of male mating competition. We find that males exhibit many signs of the costs of indirect competition, such as energetic consequences of reduced feeding and high copulation rates. During periods of more direct contest, such as during dominance instability, males are also characterized by high androgen and GC concentrations among high-ranking individuals. Consistent with relatively weak direct male–male competition, male red skin coloration appears to be more related to female choice (intersexual selection) than the signaling of dominance status (intrasexual selection). Forty-five years of life-history data show that male mortality is higher during the mating than the birth season, a pattern we hypothesize to be linked to the costs associated with mating activity. We finish by discussing unresolved issues, such as the costs of sperm competition and the data that are needed to address them.  相似文献   

13.
For gregarious species, individuals must maintain cohesion while minimizing the costs of coordinated travel. Leaders of group movements potentially influence energy expenditure, energy intake, and predation risk for individuals in the group, which can have important fitness consequences. Models of pair-living species predict that energetic asymmetries lead to an emergent leader, with those in greater need leading. We investigated sex differences in leadership in pairs of red-bellied lemurs, Eulemur rubriventer, a monomorphic species with bisexual dispersal and no discernible hierarchy, to determine whether higher energetic requirements by adult females lead to female leadership. We collected leadership data in Ranomafana National Park, Madagascar on six groups of habituated E. rubriventer for 13 consecutive months between 2004-2005. To determine whether females led group movements more than males, we examined the difference in leadership frequencies of progressions in adult males and adult females within each group (n = 1,346 progressions). We further investigated the behavioral context (i.e. travel followed by feeding or not) and seasonal contexts (fruit availability, reproduction) of leadership. Group leadership was distributed, with different individuals leading the group at different times. However, females led significantly more than males, a pattern which was consistent in both feeding and non-feeding contexts and throughout all fruiting seasons and reproductive stages. While disparities in energetic status among the sexes may impact leadership in this species, leadership did not differ with changes in food availability or reproductive stage, and thus we were unable to determine whether female leadership might be related to changes in energetic status. Females may have higher energetic needs than males at all times, not merely seasonally, or female leadership may be unrelated to immediate energetic need. Rather, female leadership may be a legacy of female dominance not currently expressed in other contexts.  相似文献   

14.
Mating males of the water strider Gerris remigisproduce vibratory signals when-single males grasp mating pairs. When played through live females with dead males on their backs, these signals repelled mating attempts by single males. A previous study showed that male mate-guarding enhances female foraging effectiveness in this species. Thus male mate-guarding signals also enhance female foraging effectiveness.  相似文献   

15.
Male primates living in multimale groups tend to direct mate and mate-guarding choices toward females of high reproductive value, i.e., high-ranking, parous females, or females with which they share strong bonds. Little is known, however, about the constraints that may limit male mate-guarding choices (the costs of this behavior) and the influence of the females’ quality on male investment in mate-guarding. We aimed to study the effects of female rank, parity status, and male–female social bond strength on the costs of and investment in mate-guarding by males. We carried out our study during two reproductive seasons on three groups of wild long-tailed macaques in Indonesia. We combined behavioral observations on male locomotion and activity with noninvasive measurements of fecal glucocorticoids (fGC). Males spent less time feeding when mate-guarding nulliparous females than when mate-guarding parous females and tended to have higher fGC levels when mate-guarding low-ranking nulliparous females than when mate-guarding high-ranking nulliparous ones. Evolution should thus favor male choice for high-ranking parous females because such a decision brings benefits at proximate (reduced costs of mate-guarding) and ultimate (higher reproductive value) levels. Further, male investment in mate-guarding was flexible and contingent on female reproductive and social value. Males were more vigilant and more aggressive toward other males when mate-guarding females to which they were strongly bonded and/or high-ranking ones than when mate-guarding other females. Our findings bring a new dimension to the study of mate choice by showing that males not only mate preferentially with high-quality females but may also aim to secure paternity with these females through optimized monopolization.  相似文献   

16.
Fecal glucocorticoid (fGC) concentrations are reliable, non-invasive indices of physiological stress that provide insight into an animal's energetic and social demands. To better characterize the long-term stressors in adult members of a female-dominant, seasonally breeding species - the ring-tailed lemur (Lemur catta) - we first validated fecal samples against serum samples and then examined the relationship between fGC concentrations and seasonal, social, demographic, genetic, and reproductive variables. Between 1999 and 2006, we collected 1386 fecal samples from 32 adult, semi-free-ranging animals of both sexes. In males and non-pregnant, non-lactating females, fGC concentrations were significantly elevated during the breeding season, specifically during periods surrounding known conceptions. Moreover, group composition (e.g., multi-male versus one-male) significantly predicted the fGC concentrations of males and females in all reproductive states. In particular, the social instability introduced by intra-male competition likely created a stressor for all animals. We found no relationship, however, between fGC and the sex, age, or heterozygosity of animals. In reproducing females, fGC concentrations were significantly greater during lactation than during the pre-breeding period. During pregnancy, fGC concentrations were elevated in mid-ranking dams, relative to dominant or subordinate dams, and significantly greater during the third trimester than during the first or second trimesters. Thus, in the absence of nutritional stressors, social dominance was a relatively poor predictor of fGC in this female-dominant species. Instead, the animals were maximally challenged by their social circumstances and reproductive events—males by competition for mating opportunities and females by late-term gestation and lactation.  相似文献   

17.
The variation in song rate during the breeding season was studied in two individually marked chaffinch Fringilla coelebs populations. We gathered data to investigate especially the recently presented mate-guarding hypothesis. The active singing has been supposed to function as a form of mate guarding during the female's fertile period by announcing the high status of the male and preventing extra-pair copulations by neighbouring males. There was no clear dawn chorus in the chaffinch, i.e. a peak in the song rate before sunrise. Male chaffinches continued to sing after mating, but the song rate dropped significantly. In contrast to the mate-guarding hypothesis the song rate was lower during the fertile period of the female than during pre-mating and incubation. Thus, the males do not announce the fertility status of their mates or their own quality and status by active singing. The song does not function as a form of mate guarding in the chaffinch. One function of the song of the chaffinch is mate attraction: singing activity was highest before pair formation in early spring and decreased after mating but increased again if the male lost his mate later in the breeding season.  相似文献   

18.
Japanese macaques inhabit a relatively cold environment and females of this species could have developed strategies of energy economy to face the sometimes-harsh seasonal conditions of temperate climates, as well as reproductive costs, and thus regulate their energy balance. Here, we explore the relationship between nutritional status, body composition, seasonality, and reproductive status using isotope-labeled water, anthropometric measurements, and leptin assays from 14 captive female Japanese macaques. Our results indicated that body mass provided the best predictor of fat-free mass and fat mass. These females varied in estimated percent body fat between 8 and 25% (18% on average at the beginning of the mating season and 13% during the birth season). Higher body mass and body fat content were observed at the beginning of the mating season, which supports the hypothesis that individual females need to attain a sufficient physical condition to cover energy costs associated with mating activity, and to survive under severe ecological conditions in winter with high thermoregulatory costs. We found a relationship between conception rates and energetic condition or body fat, with females that conceived during one mating season being fatter after the end of their previous mating season. Together, these results suggest that, even in captive settings with constant food availability, seasonal breeding entails relatively high energy costs, and that females with higher energy status could invest more in reproductive activities and could afford to reproduce more rapidly.  相似文献   

19.
Male field crickets (Gryllinae: Gryllidae: Orthoptera) vary in their mating strategies, particularly in whether they call from defended sites to attract phonotactic females or roam silently in search of potential mates. To better understand the economics underlying these alternative strategies, respirometry was employed to examine the energetic costs of each strategy's component behaviors for a representative species, Acheta domesticus. Advertisement calling in this species, composed of low pulse rate chirps, is an order of magnitude less energetically costly than walking per unit time. However, for gryllids that advertise call with higher pulse rate trills, calling and walking appear to be of equivalent energetic cost. Thus, if energetic costs are important in determining grylline mating strategies, trillers and chirpers should have different sensitivities to change in factors affecting the relative payoffs of each strategy. Field studies of changes in mating behavior with increased population density support this argument. This study also determined that courtship calling by A. domesticus was over twice as energetically costly as advertisement calling per unit time, suggesting its importance as a more reliable indicator of signaler, or mate, quality.  相似文献   

20.
Researchers have suggested that several types of agonistic and affiliative behavior covary as a set of species-specific traits, and have used the term dominance style to describe the covariation. We compared measures of dominance style between a group of Assamese macaques (Macaca assamensis) and a group of rhesus macaques (M. mulatta), though kinship information was unknown. Assamese and rhesus female-female dyads each showed a low proportion of counter aggression and a low conciliatory tendency, suggesting that they have despotic social relationships. They also showed a despotic pattern on several other types of agonistic and affiliative behavior, such as approach outcomes and grooming distributions, which is consistent with the covariation of dominance style traits. Assamese male-male dyads showed relatively high levels of reconciliation and counter aggression versus other macaque males portrayed in the literature, suggesting that Assamese males have a tolerant dominance style. Insofar as macaque dominance style depends on the behavior of females, we suggest that Assamese macaques, like rhesus macaques, have despotic social relationships, which contrasts with evidence of a strong correlation between phylogeny and dominance style in macaques. Further, our results indicate that strong male bonding and tolerant dominance relationships among males are independent of female dominance style. Lastly, some measures of agonistic behavior, such as rate of aggression or proportion of bites, are likely altered in competitive environments and thus are not useful indicators of dominance style.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号