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1.
Craig B. Stanford 《American journal of primatology》1991,25(1):35-47
Data from a 15–month field study of the capped langur (Presbytis pileata) in moist deciduous forest in Bangladesh show that during intergroup encounters males respond more aggressively to extra-group males and to the resident males of unfamiliar one-male groups than they do toward familiar males. Lone males followed established one-male groups and attempted to interact with group females. During intergroup encounters males responded to the approach of unfamiliar males with significantly more displays than were given to familiar (frequently encountered) males. The frequency of displays given to approaching groups showed a negative correlation with the frequency of encounters with those groups. In 50% of intergroup encounters males pushed and bit their group females if the females strayed from the immediate proximity of the group male. Further observations suggest that males obtain females that have emigrated from established groups or attempt to interact with them in established onemale groups. Males had a tenure from at least 13 months to at least 26 months, and between 1986 and 1988 no male changes were seen. Capped langur males defended females from other males, but females did not defend resources or participate in intergroup encounters. The implications of this sex difference in behavior during encounters is discussed with regard to ecological models of female-bonded primate groups. 相似文献
2.
Carey P. Yeager 《American journal of primatology》1990,20(2):95-106
Proboscis monkey (Nasalis larvatus) social organization was studied at the Tanjung Puting National Park in Kalimantan Tengah, Indonesia, for 12 months. Data were collected on one-male groups and all-male groups by using scan sampling and event sampling while following groups. Evening census surveys were also conducted. Proboscis monkeys were found to follow the typical Asian colobine pattern of one-male social groups, with extra-group males forming all-male groups. These groups appear stable, with few changes in membership. One-male groups appear to be “female bonded”; adult females direct affiliative behaviors towards their offspring and other adult females, not towards the male. Nearest-neighbor data indicate some peripheralization of juvenile animals. 相似文献
3.
Elise Huchard Michel Raymond Julio Benavides Harry Marshall Leslie A Knapp Guy Cowlishaw 《BMC evolutionary biology》2010,10(1):96
Background
Males from many species are believed to advertise their genetic quality through striking ornaments that attract mates. Yet the connections between signal expression, body condition and the genes associated with individual quality are rarely elucidated. This is particularly problematic for the signals of females in species with conventional sex roles, whose evolutionary significance has received little attention and is poorly understood. Here we explore these questions in the sexual swellings of female primates, which are among the most conspicuous of mammalian sexual signals and highly variable in size, shape and colour. We investigated the relationships between two components of sexual swellings (size and shape), body condition, and genes of the Major Histocompatibility Complex (MHC) in a wild baboon population (Papio ursinus) where males prefer large swellings. 相似文献4.
Paul N. Newton 《International journal of primatology》1987,8(3):199-232
The social organization of hanuman langurs (Presbytis entellus;Colobinae) was studied in Kanha Tiger Reserve, Central Indian Highlands, for 2300 hr (1980–1985), in a mosaic of moist deciduous
forest and anthropogenic meadow. The langur population density was 46.15/km
2 and the mean troop and band sizes were 21.7 and 14.0, respectively. Of 14 troops, 13 were one-male and 1 was trimale. The
population adult sex ratio was 1:2.5. The majority of female sexual solicitations was directed toward the harem male. The
birth season was December to May, with an estimated gestation of 171–224 days. A review of langur reproductive seasonality
suggests that breeding throughout the year is confined to those populations able to exploit human food sources. Mortality
during the first year of life was 40%, including infanticide. A significant positive correlation was found between the age
of an infant at death or disappearance and the mother’s subsequent interbirth interval. Five cases of social change are described,
including female transfer, one-male to multimale change, troop formation, and gradual and rapid replacement of troop males.
Takeover-associated infant killing by band males, in an undisturbed moderate-density population, supported the sexual-selection/infanticide
hypothesis but not the social-pathology hypothesis. However, it could not be directly confirmed that an invading infanticidal
male gains a reproductive advantage. The male tenure of harems was estimated to be 45 months. 相似文献
5.
Carey P. Yeager 《American journal of primatology》1991,23(2):73-86
Proboscis monkey (Nasalis larvatus) social organization was studied at the Natai Lengkuas station, Tanjung Puting National Park in Kalimantan Tengah, Indonesia. Data were collected on ten one-male groups and two all-male groups using scan sampling and event sampling during follows, and through evening census surveys. Proboscis monkeys were found to form stable one-male groups. Specific groups associated at their sleeping sites, in a manner similar to the fission-fusion pattern described for hamadryas and gelada baboons. Analyses performed on these associations indicated that the groups formed two separate bands. These separate bands appear to be a secondary level of organization, distinct from the primary level of organization, the one-male and all-male groups. This is the first evidence for such a two-tiered system of organization in an arboreal colobine species. Proboscis monkeys closely resemble gelada baboons in their organizational pattern. In both species, adult females direct the majority of their affiliative behavior towards their offspring and other adult females, males do not engage in active herding, all-male groups are present, and one-male groups do spend time apart from other groups. Home ranges of both groups and of bands of proboscis monkeys overlapped extensively; temporal avoidance between bands may have been mediated by early morning vocalizations and branch shaking displays. 相似文献
6.
Emily Engelbrecht‐Wiggans James P. Tumulty 《Ethology : formerly Zeitschrift fur Tierpsychologie》2019,125(12):957-964
Sexual dichromatism is widespread among animals, but examples of “reverse” sexual dichromatism, in which females are more brightly colored than males, are extremely rare. We discovered a unique case of reverse sexual dichromatism in the golden rocket frog (Anomaloglossus beebei), a diurnal Neotropical frog. Females are bright “golden” in color, and males are drab tan with brown pigmentation that darkens when they are calling. Here, we document this color variation with calibrated digital photography and further show that there is no evidence for sex‐specific habitat matching; both sexes live in the same well‐lit habitat on green bromeliad leaves. Our results suggest that color variation in this species is an intraspecific signal and provide an important exception to the general expectation that males are more visually conspicuous in species with conventional sex roles. 相似文献
7.
Cyclical changes in the vulvae of five adult lar gibbons (Hylobates [H.] lar) were studied and compared with those of eight lowland gorillas. The results reveal that the gibbons have relatively conspicuous and specialized sexual swellings that alter shape and appearance during the ovarian cycle. At maximum extent, the genital swellings of gorillas are relatively and absolutely smaller than those of gibbons, and lack the distinctive coloration seen in the genital swellings of the smaller apes. We conclude that the female gibbon's sexual swelling is a far more conspicuous and effective signal of estrus status than that of the gorilla, and that this is not explicable in terms of allometry. Previous investigators have pointed to one-male mating systems, monogamous pair-bonding, or an arboreal habitat as reasons that some primates should have less conspicuous signals of estrus than others. Our findings for the gibbon are the reverse of these predictions, and indicate that sexual selection other than by intermale competition for estrous females is implicated in the ultimate causation of the gibbon's swelling. The adaptive value and significance of the female gibbon's sexual signals remain unclear, however. 相似文献
8.
Asian colobines typically live in small one-male groups (OMGs) averaging five adult females, but Simias concolor (simakobu or pig-tailed langur) is considered an exception because mostly adult male-female pairs have been reported. However, based on their phylogenetic position and marked sexual dimorphism, simakobu are also expected to form OMGs with multiple females. The preponderance of small groups could be the result of human disturbance (hunting or habitat disturbance) reducing group size in the recent past. To investigate this possibility, we documented the demography of ten wild simakobu groups from January 2007 until December 2008 at an undisturbed site, the Peleonan Forest, Siberut Island, Indonesia. We assessed the population-specific size and composition of groups and documented demographic changes due to births, disappearances, and dispersals throughout our 2-year study. We found OMGs with 3.0 adult females on average in addition to all-male groups, but no adult male-female pairs. The ratio of 0.5 infants per adult female (and 0.64 births per female-year in focal groups) suggested that birth rates were similar to those of other Asian colobines. In 5.1 group-years, we observed six dispersal events and six temporary presences (i.e., less than 3 months' residency). Both males and females dispersed, and juveniles seemed to disperse more frequently than adults. To assess the impact of human disturbance on simakobu demography, we compiled data for seven additional populations from the literature and compared them using multiple regressions. Adult sex ratio and the number of immatures per group were influenced negatively by hunting and positively by habitat disturbance while reproductive rates were not significantly affected by either variable. These findings suggest that adult male-female pairs may result from hunting pressure reducing group size, and that conservation action to reduce hunting in the Mentawai Islands is needed to ensure the survival of this critically endangered species. 相似文献
9.
Previous studies have suggested that there is a strong relationship between a high degree of aggressive competition among
males for access to fertile females and large body and canine size in males. It has further been suggested that such a relationship
among living primates can be used to infer the social organization of extinct primate species from the degree of sexual dimorphism
exhibited.
Our field studies of patas (Erythrocebus patas) and blue monkeys (Cercopithecus mitis), two species which had previously been characterized as having one-male ‘harem’ group structures, indicate considerable
variability in mating systems. We suggest, on the basis of our observations of these species, that factors other than male-male
competition (e.g., predation) may also have influenced the degree of dimorphism in primates. 相似文献
10.
Sexual competition and N supply interactively affect the dimorphism and competiveness of opposite sexes in Populus cathayana
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JUAN CHEN TINGFA DONG BAOLI DUAN HELENA KORPELAINEN ÜLO NIINEMETS CHUNYANG LI 《Plant, cell & environment》2015,38(7):1285-1298
Several important dioecious species show sexual spatial segregation (SSS) along environmental gradients that have significant ecological effect on terrestrial ecosystem. However, little attention has been paid to understanding of how males and females respond to environmental gradients and sexual competition. We compared eco‐physiological parameters of males and females of Populus cathayana under different sexual competition patterns and nitrogen (N) supply levels. We found that males and females interacting with the same or opposite sex showed significant differences in biomass partition, photosynthetic capacity, carbon (C) and N metabolism, and leaf ultrastructure, and that the sexual differences to competition were importantly driven by N supply. The intersexual competition was enhanced under high N, while the intrasexual competition among females was amplified under low N. Under high N, the intersexual competition stimulated the growth of the females and negatively affected the males. In contrast, under low N, the males exposed to intrasexual competition had the highest tolerance, whereas females exposed to intrasexual competition showed the lowest adaptation among all competition patterns. Sexual competition patterns and N supply levels significantly affected the sexual dimorphism and competitiveness, which may play an important role in spatial segregation of P. cathayana populations. 相似文献
11.
For primates, as for many other vertebrates, copulation which results in ejaculation is a prerequisite for reproduction. The
probability of ejaculation is affected by various physiological and social factors, for example reproductive state of male
and female and operational sex-ratio. In this paper, we present quantitative and qualitative data on patterns of sexual behaviour
in a captive group of hamadryas baboons (Papio hamadryas), a species with a polygynous–monandric mating system. We observed more than 700 copulations and analysed factors that can
affect the probability of ejaculation. Multilevel logistic regression analysis and Akaike’s information criterion (AIC) model
selection procedures revealed that the probability of successful copulation increased as the size of female sexual swellings
increased, indicating increased probability of ovulation, and as the number of females per one-male unit (OMU) decreased.
In contrast, occurrence of female copulation calls, sex of the copulation initiator, and previous male aggression toward females
did not affect the probability of ejaculation. Synchrony of oestrus cycles also had no effect (most likely because the sample
size was too small). We also observed 29 extra-group copulations by two non-adult males. Our results indicate that male hamadryas
baboons copulated more successfully around the time of ovulation and that males in large OMUs with many females may be confronted
by time or energy-allocation problems. 相似文献
12.
The expression of secondary sexual traits in females has often been attributed to a correlated response to selection on male traits. In rare cases, females have secondary sexual traits that are not homologous structures to secondary sexual traits in males and are thus less likely to have evolved in females because of correlated selection. In this study, we used the dung beetle Onthophagus sagittarius, a species with sex‐specific horns, to examine the environmental and quantitative genetic control of horn expression in males and females. Offspring subjected to different brood mass manipulations (dung addition/removal) were found to differ significantly in body size. Brood mass manipulation also had a significant effect on the length of male horns; however, female horn length was found to be relatively impervious to the treatment, showing stronger patterns of additive genetic variance than males. We found no correlations between horn expression in males and females. We therefore conclude that the horns of O. sagittarius females are unlikely to result from genetic correlations between males and females. Rather, our data suggest that they may be under independent genetic control. 相似文献
13.
Md Kawsar Khan 《Evolution; international journal of organic evolution》2020,74(10):2293-2303
Conspicuous female coloration can evolve through male mate choice or via female-female competition thereby increasing female mating success. However, when mating is not beneficial, such as in pre-reproductive females, selection should favor cryptic rather than conspicuous coloration to avoid male detection and the associated harassment. Nevertheless, conspicuous female coloration occurs in many prereproductive animals, and its evolution remains an enigma. Here, I studied conspicuous female coloration in Agriocnemis femina damselflies, in which the conspicuous red color of the immature females changes to a less conspicuous green approximately a week after their emergence. I measured body size, weight, and egg numbers of the female morphs and found that red females are smaller and lighter and do not carry developed eggs. Finally, I calculated the occurrence frequency and mating frequency of red and green females in several populations over a three-year period. The results demonstrate that red females mated less frequently than green females even when red females were the abundant morph in the populations. I concluded that conspicuous female coloration is likely to function as a warning signal of sexual unprofitability, thereby reducing sexual harassment for females and unprofitable mating for males. 相似文献
14.
Shun Hongo Yoshihiro Nakashima Etienne François Akomo-Okoue Fred Loïque Mindonga-Nguelet 《International journal of primatology》2016,37(3):416-437
The correlates of variation in the number of males in primate groups form a long-standing question in primatology. We investigated female reproductive seasonality and the numbers of males in groups of wild mandrills (Mandrillus sphinx) in a 25-month camera-trap survey with 160 camera locations in Moukalaba-Doudou National Park, Gabon. We used 1760 videos to analyze group composition, including the presence of females with newborn infants and with sexual swellings, the number of males present in groups, and male spatial positioning in groups. Female reproduction was seasonal, with a peak in the number of newborns in the mid-rainy season and a peak in the number of females with sexual swellings in the early dry season. The number of males in the group increased in the dry season, with a much greater increase in the number of mature males (sevenfold) than in submature males (twofold). The peak number of mature males, but not submature males, in the group lagged significantly behind the peak in the number of females with sexual swellings, suggesting that submature males enter groups before mature males and/or that mature males stay in the group longer after the peak of females with sexual swellings. Mature, but not submature, males appeared frequently near females with sexual swellings. In conclusion, we found a clear relationship between the presence of receptive females and the number of males in the group, and evidence that male competitive ability influences male strategies. 相似文献
15.
Multivariate genetic architecture of the Anolis dewlap reveals both shared and sex‐specific features of a sexually dimorphic ornament
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R. M. Cox R. A. Costello B. E. Camber J. W. McGlothlin 《Journal of evolutionary biology》2017,30(7):1262-1275
Darwin viewed the ornamentation of females as an indirect consequence of sexual selection on males and the transmission of male phenotypes to females via the ‘laws of inheritance’. Although a number of studies have supported this view by demonstrating substantial between‐sex genetic covariance for ornament expression, the majority of this work has focused on avian plumage. Moreover, few studies have considered the genetic basis of ornaments from a multivariate perspective, which may be crucial for understanding the evolution of sex differences in general, and of complex ornaments in particular. Here, we provide a multivariate, quantitative‐genetic analysis of a sexually dimorphic ornament that has figured prominently in studies of sexual selection: the brightly coloured dewlap of Anolis lizards. Using data from a paternal half‐sibling breeding experiment in brown anoles (Anolis sagrei), we show that multiple aspects of dewlap size and colour exhibit significant heritability and a genetic variance–covariance structure ( G ) that is broadly similar in males ( G m) and females ( G f). Whereas sexually monomorphic aspects of the dewlap, such as hue, exhibit significant between‐sex genetic correlations (rmf), sexually dimorphic features, such as area and brightness, exhibit reduced rmf values that do not differ from zero. Using a modified random skewers analysis, we show that the between‐sex genetic variance–covariance matrix ( B) should not strongly constrain the independent responses of males and females to sexually antagonistic selection. Our microevolutionary analysis is in broad agreement with macroevolutionary perspectives indicating considerable scope for the independent evolution of coloration and ornamentation in males and females. 相似文献
16.
Baboon sexual swellings and male response: A possible operational mammalian supernormal stimulus and response interaction 总被引:3,自引:0,他引:3
Experimental work using coagulated masturbatory seminal emissions from nine adult male chacma baboons (Papio ursinus)as a dependent variable revealed that males show a greater sexual arousal response to female conspecifics exhibiting exaggerated
perineal swellings. The menstrual cycles of the “superswollen” females did not differ in length or patterning from the controls.
Since additional experimental work, including behavioral observations on females with normal and supersized swellings, failed
to reveal differences in female proceptivity, the male’s increased arousal response appears dependent upon the perineal size per se.The males’ responses suggest that the supersized swellings may be an example of an operational visual supernormal stimulus
and response interaction. 相似文献
17.
In the olive colobus (Procolobus verus), many groups have multiple males and the males have large testes. This indicates that even though this species lives in small groups, single males do not monopolize the groups. We investigated the strategies employed by males to secure their mating success, and sought to determine whether the lack of male monopolization was a result of female mating strategies, as indicated by the exaggerated sexual swellings of the females. Four study groups were monitored for demographic changes, and group composition was determined in six additional groups in Taï National Park, Ivory Coast, between 1994 and 1999. Social behavior was recorded by scan and focal sampling in the study groups. The almost permanent association of olive colobus with Diana monkeys (Cercopithecus diana) in effect provided males a resource at which they could expect females to visit and sometimes even permanently join them, as well as protection from predators. As alternative strategies for obtaining females, one male took over the group of another male and one male immigrated into a bisexual group. Within bi‐male groups, dominant males mated most frequently and males defended their groups during intergroup interactions. Lone females that visited groups or solitary males had a swelling more often than expected, and generally mated with the males they visited. Females had long receptive periods, several consecutive receptive cycles, and some overlap in receptive periods within groups. Females mated with extragroup males, and during infertile periods. We concluded that the males used the Diana monkeys for safety reasons and to obtain mating partners, and that female reproductive biology and behavior prevented the monopolization of groups of females by single males. Our data were inconclusive as regards the benefits to females of avoiding monopolization by males. Am. J. Primatol. 62:261–273, 2004. © 2004 Wiley‐Liss, Inc. 相似文献
18.
Theory predicts that the sex making greater investments into reproductive behaviours demands higher cognitive ability, and as a consequence, larger brains or brain parts. Further, the resulting sexual dimorphism can differ between populations adapted to different environments, or among individuals developing under different environmental conditions. In the nine‐spine stickleback (Pungitius pungitius), males perform nest building, courtship, territory defence and parental care, whereas females perform mate choice and produce eggs. Also, predation‐adapted marine and competition‐adapted pond populations have diverged in a series of ecologically relevant traits, including the level of phenotypic plasticity. Here, we studied sexual dimorphism in brain size and architecture in nine‐spined stickleback from marine and pond populations reared in a factorial experiment with predation and food treatments in a common garden experiment. Males had relatively larger brains, larger telencephala, cerebella and hypothalami (6–16% divergence) than females, irrespective of habitat. Females tended to have larger bulbi olfactorii than males (13%) in the high food treatment, whereas no such difference was found in the low food treatment. The strong sexual dimorphism in brain architecture implies that the different reproductive allocation strategies (behaviour vs. egg production) select for different investments into the costly brains between males and females. The lack of habitat dependence in brain sexual dimorphism suggests that the sex‐specific selection forces on brains differ only negligibly between habitats. Although significance of the observed sex‐specific brain plasticity in the size of bulbus olfactorius remains unclear, it demonstrates the potential for sex‐specific neural plasticity. 相似文献
19.
Sexual dimorphism in conspicuousness and ornamentation in the enigmatic leaf‐nosed lizard Ceratophora tennentii from Sri Lanka
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Martin J. Whiting Daniel W.A. Noble Ruchira Somaweera 《Biological journal of the Linnean Society. Linnean Society of London》2015,116(3):614-625
Measures of physiological performance capacity, such as bite force, form the functional basis of sexual selection. Information about fighting ability may be conveyed through a structural feature such as a rostrum (i.e. horn) or a colour signal and thereby help reduce costly conflict. We quantified sexual dimorphism in key traits likely to be the targets of sexual selection in Tennent's leaf‐nosed lizard (Ceratophora tennentii) from Sri Lanka, and examined their relationship to bite force and body condition. We found body length and bite force to be similar for males and females. However, head length was significantly greater in males and they had significantly more conspicuous throats and labials (chromatic contrast and luminance) than females. Males also had a proportionally larger rostrum, which we predicted could be an important source of information about male quality for both sexes. Rostrum length was correlated with throat chromatic contrast in males but not females. Nonetheless, the rostrum and aspects of coloration did not correlate with bite force or body condition as we predicted. We have no information on contest escalation in this species but if they rarely bite, as suggested by a lack of difference in bite force between males and females, then bite force and any associated signals would not be a target of selection. Finally, males and females had similar spectral reflectance of the mouth and tongue and both had a peak in the ultra‐violet, and were conspicuous to birds. Lizards only gaped their mouths during capture and not when threatened by a potential predator (hand waving). We hypothesize that conspicuous mouth colour may act as a deimatic signal, startling a potential predator, although this will need careful experimental testing in the future. 相似文献
20.
Debbie Guatelli‐Steinberg Rebecca J. Ferrell Jennifer Spence Tiffany Talabere Amelia Hubbard Stacey Schmidt 《American journal of physical anthropology》2009,140(2):216-233
Previous research has demonstrated that great ape and macaque males achieve large canine crown sizes primarily through extended canine growth periods. Recent work has suggested, however, that platyrrhine males may achieve larger canine sizes by accelerating rather than prolonging growth. This study tested the hypothesis that the ontogenetic pathway leading to canine sexual dimorphism in catarrhines differs from that of platyrrhines. To test this hypothesis, males and females of several catarrhine genera (Hylobates, Papio, Macaca, Cercopithecus, and Cercocebus) and three platyrrhine genera (Cebus, Ateles, and Callicebus) were compared in the number and spacing of perikymata (enamel growth increments) on their canine crowns. In addition, perikymata periodicities (the number of days of growth perikymata represent) were determined for five genera (Hylobates, Papio, Macaca, Cebus, and Ateles) using previously published as well as original data gathered for this study. The central findings are as follows: 1) males have more perikymata than females for seven of eight genera (in five of the seven, the differences are statistically significant); 2) in general, the greater the degree of sexual dimorphism, the greater the sex difference in male and female perikymata numbers; 3) there is no evidence of a systematic sex difference in primate periodicities; and 4) there is some evidence that sex differences in enamel formation rates may make a minor contribution to canine sexual dimorphism in Papio and Cercopithecus. These findings strongly suggest that in both catarrhines and platyrrhines prolongation of male canine growth is the primary mechanism by which canine crown sexual dimorphism is achieved. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc. 相似文献