Contribution of adult sex ratio to trauma and reproductive output in large breeding groups of rhesus macaques (Macaca mulatta)

2021 ◽  
Vol 30 (4) ◽  
pp. 479-492
Author(s):  
J Crast ◽  
MA Bloomsmith ◽  
CM Remillard ◽  
T Meeker

Maintaining stable breeding groups of rhesus macaques (Macaca mulatta) can be challenging due to the complex social dynamics and despotic nature of the species. Trauma from aggression is a common problem in rhesus colonies and can cause social disruption, strain veterinary and animal management resources, and potentially affect reproduction. Previous research has shown that increasing the number of non-natal adult males in a breeding group can improve group stability, reduce trauma, and increase reproduction. Here, we used mixed-effects regression models to examine the effects of sex ratio and other factors on trauma and reproduction at the Yerkes National Primate Research Center using a historical dataset made up of four large rhesus groups over an eleven-year period (2003–2013). As expected, sex ratio was a significant predictor for both trauma and reproduction. However, group age since formation was a stronger predictor of trauma frequency and the amount of space available was a slightly better predictor of reproduction than sex ratio or trauma. These results indicate that improving sex ratios can be a viable management strategy to reduce trauma and improve reproduction, particularly when it is difficult to manipulate the group compositions and/or their housing situations. Reducing trauma is a primary goal for rhesus breeding colonies, as it directly impacts the monkeys' health and psychological well-being. Such improvements are necessary for the ethical treatment and care of the animals themselves, but also to reduce financial burdens and maintain a healthy colony for research purposes.

Gesture ◽  
2005 ◽  
Vol 5 (1-2) ◽  
pp. 57-73 ◽  
Author(s):  
Dario Maestripieri

The present study compared the frequency and contextual usage of the most prominent gestural signals of dominance, submission, affiliation, and bonding in rhesus, pigtail, and stumptail macaques living in captivity. Most similarities among species were found in signals of dominance and submission and most differences in affiliative gestures and bonding patterns. Rhesus macaques have a relatively poor gestural repertoire, pigtail macaques possess conspicuous signals of affiliation and bonding, and stumptail macaques have the richest repertoire of assertive and submissive signals. The similarities and differences in the gestural repertoires of rhesus, pigtail, and stumptail macaques can be related to the intragroup social dynamics of these species as well as to their evolutionary history.


2017 ◽  
Vol 4 (1) ◽  
pp. 117-125
Author(s):  
Ivanela Kondova ◽  
Gerco Braskamp ◽  
Peter J. Heidt ◽  
Wim Collignon ◽  
Tom Haaksma ◽  
...  

Abstract. Endometriosis is a poorly understood common debilitating women's reproductive disorder resulting from proliferative and ectopic endometrial tissue associated with variable clinical symptoms including dysmenorrhea (painful menstrual periods), dyspareunia (pain on intercourse), female infertility, and an increased risk of malignant transformation. The rhesus macaque (Macaca mulatta) develops a spontaneous endometriosis that is very similar to that seen in women. We hypothesized that specific major histocompatibility complex (MHC) alleles may contribute to the pathogenesis of endometriosis. As part of a collaboration between the Biomedical Primate Research Centre (BPRC) in the Netherlands and the New England Primate Research Center (NEPRC) in the United States, we analyzed DNA sequences of MHC class I (Macaca mulatta, Mamu-A1) and class II (Mamu-DRB) alleles from rhesus macaques with endometriosis and compared the allele frequencies with those of age-matched healthy macaques. We demonstrate that two MHC class I alleles are overrepresented in diseased macaques compared to controls: Mamu-A1*001, 33.3 % in BPRC animals with endometriosis vs. 11.6 % in healthy macaques (p =  0.007), and Mamu-A1*007, 21.9 % NEPRC rhesus macaques vs. 6.7 %, (p =  0.003). We provide evidence that select MHC class I alleles are associated with endometriosis in rhesus macaques and suggest that the disease pathogenesis contribution of MHC class I warrants further research.


2019 ◽  
Vol 30 (4) ◽  
pp. 883-893 ◽  
Author(s):  
James A Cox ◽  
Jessica A Cusick ◽  
Emily H DuVal

Abstract A biased adult sex ratio (ASR) can influence cooperative breeding behavior if the bias limits mating opportunities for the more abundant sex. We tested predictions associated with the ASR-cooperation hypothesis in the brown-headed nuthatch (Sitta pusilla). We manipulated ASR by cross-fostering known-sex nestlings within 2 large (≥100 ha) experimental plots for 5 years using a crossover design where each plot received an opposing male- or female-biased treatment for 2 consecutive years. A year with no manipulations followed before the bias was reversed on each plot for 2 additional years. Variation in ASR (adult males/total adults) was pronounced compared to background proportions (0.55) and ranged from a female bias in female-biased plots (0.47) to a strong male bias in male-biased plots (0.71). Sex ratios during the postbreeding period ranged more broadly (0.33 in female-biased plots vs. 0.74 in male-biased plots). Territory densities did not change significantly and allowed 6 predictions to be assessed. Consistent with predictions, the prevalence of cooperative breeding groups doubled under male-biased treatments and large cooperative groups appeared (≥2 male helpers vs. the single male helper most common prior to the experiment). These changes occurred despite increased dispersal of cross-fostered males in male-biased plots. Most juvenile females dispersed, but, consistent with predictions, the prevalence of female helpers increased under female-biased treatments. Manipulations did not alter the sex of nestlings produced nor extend the time that males served as helpers. Taken collectively, results support the ASR-cooperation hypothesis and the role that mate limitations play in cooperative breeding behavior.


Parasitology ◽  
2004 ◽  
Vol 130 (1) ◽  
pp. 99-107 ◽  
Author(s):  
A. STIEN ◽  
M. DALLIMER ◽  
R. J. IRVINE ◽  
O. HALVORSEN ◽  
R. LANGVATN ◽  
...  

Estimates of the intensity and abundance of species provide essential data for ecological, evolutionary and epidemiological studies of gastrointestinal nematode communities. These estimates are typically derived from the species composition of adult males when only males have readily scorable species-specific morphological traits. Such estimation assumes that all species in the community have the same adult sex ratio. We evaluated this assumption for the trichostrongyle nematodes Ostertagia gruehneri and Marshallagia marshalli in infracommunities in Svalbard reindeer by identifying to species adult females using a polymerase chain reaction assay. The proportion of males was found to be slightly higher in O. gruehneri than in M. marshalli. Evidence for seasonal variation and density dependence in the adult sex ratio was only found for O. gruehneri. Possible demographic mechanisms for such sex ratio variation are discussed, and stochastic models that generate density-dependent sex ratios proposed. Sex ratio variation caused substantial bias in some male-based estimates of intensity of infection, while substantial and consistent bias in estimates of abundances was only evident in late winter samples. Our results suggest that estimating sex ratios can be particularly important in individual host level studies of nematode species of low abundance.


1990 ◽  
Vol 68 (3) ◽  
pp. 547-555 ◽  
Author(s):  
Adrian Hailey

Survival, recruitment, and dynamics of adult Testudo hermanni at Alyki (northern Greece) were studied from 1980 to 1988. Recruitment of adult males was greater than that of females owing to their shorter time to maturity (9 vs. 11 years); recruitment of subadults (6 years old) was equal in males and females. Mean annual survival was slightly greater in males (0.914) than females (0.877), equivalent to mean adult longevity values of 11.6 and 8.1 years, respectively. Excluding tortoises that die before maturity, male and female T. hermanni are mature for about 56 and 42% of their life, respectively. Generation time was roughly twice the age at maturity, and three times the age at which secondary sexual characters develop, a pattern which may apply to other tortoises. The combination of adult survival and recruitment should lead to a stable sex ratio (males/females) of 2.1. The adult sex ratio was higher than this, but decreasing, from4.1 in 1982to3.0 in 1986, with an increase in the female population; the number of males was stable. The observed sex ratio showed a similar decline and a further fall to 2.4 in 1988. The cause of the lower survival rate of females compared with males is proposed to be damage during courtship attempts. The courtship behaviour and related anatomy of T. hermanni are compared with those of T. graeca, a species with even population sex ratios. The level of male-induced female mortality would depend on population density; the increasing number of females during the study follows the approximate halving of population density in 1980.


Author(s):  
Kelly L Bailey ◽  
Leigh Anna Young ◽  
Caroline E Long ◽  
Caren M Remillard ◽  
Shannon E Moss ◽  
...  

Integrating animals into a new group is a challenge for both free-ranging and captive adult male rhesus monkeys (Macacamulatta), and for females in groups receiving new males. To ensure the genetic viability of the population, however, maletransfers must occur in both natural and captive settings. To facilitate the introduction of groups of adult males to adult females, we designed a new enclosure that is attached to the outdoor compound where females are housed. Here we describethe construction of 3 introduction enclosures, their use during 4 introductions of groups of adult males to adult females, abrief comparison of introduction success rates associated with the new introduction enclosures with those of our traditionalmale introduction method, and a critique by the various groups of staff members working with the new enclosures. Overall, the introduction enclosures benefitted both the macaques and the facility personnel and appear to be a useful enhancementto our process of integrating breeding groups.


Gesture ◽  
2005 ◽  
Vol 5 (1-2) ◽  
pp. 57-73 ◽  
Author(s):  
Dario Maestripieri

The present study compared the frequency and contextual usage of the most prominent gestural signals of dominance, submission, affiliation, and bonding in rhesus, pigtail, and stumptail macaques living in captivity. Most similarities among species were found in signals of dominance and submission and most differences in affiliative gestures and bonding patterns. Rhesus macaques have a relatively poor gestural repertoire, pigtail macaques possess conspicuous signals of affiliation and bonding, and stumptail macaques have the richest repertoire of assertive and submissive signals. The similarities and differences in the gestural repertoires of rhesus, pigtail, and stumptail macaques can be related to the intragroup social dynamics of these species as well as to their evolutionary history.


2020 ◽  
Author(s):  
Thomas Richardson

In recent years researchers studying subjective well-being have found that ecological factors may underpin societal differences in happiness. The adult sex ratio, the number of males relative to females in an environment, influences many behaviours in both humans and non-human animals. However, the possible influence of the sex ratio on subjective well-being has received little attention. I investigated the relationship between the adult sex ratio and subjective well-being in over 29000 respondents 133 regions of Europe. I find that women report lower subjective well-being in areas with more female-biased sex ratios, but males’ well-being was unaffected. I did not find that the sex ratio influences sex specific probability of marriage or marriage rates overall. I find that increased population density is associated with lower well-being. Drawing from sociological and evolutionary theories, I suggest that results may be due to their decreased bargaining power in the dating market.


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