Exaggerated Sexual Swellings and the Probability of Conception in Wild Sanje Mangabeys (Cercocebus sanjei)

© 2017, The Author(s). Females of several catarrhine primate species exhibit exaggerated sexual swellings that change in size and coloration during the menstrual cycle and, in some species, gestation. Although their function remains under debate, studies indicate that swellings may contain information males could use to discern ovulation and the probability that a cycle will be conceptive. Here we combine visual ratings of swellings with hormonal data for a group of Sanje mangabeys (18 adult, 3 adolescent females) to determine if their swellings provide reliable information on female fertility. In all cases where ovulation was detected (N=7), it occurred during maximum tumescence, and in 83.3% during the first two days of the “shiny phase,” a period during maximum tumescence when the swelling was brightest. There were no significant differences in maximum tumescence and shiny phase duration among cycles of different probability of conception, although there was a trend toward conceptive cycles exhibiting shorter shiny phases than nonconceptive ones. Only 25% (N=4) of postconceptive swellings developed the shiny phase, and adolescents displayed the longest maximum tumescence and shiny phases. The conspicuous nature of the shiny phase and the frequent overlap between its onset and ovulation suggest that its presence serves as a general signal of ovulation and that the cycle has a high probability of being conceptive. It also suggests that swellings in some Sanje mangabeys are more accurate signals of fertility than in other primates

Juggling Priorities: Female Mating Tactics in P hayre's Leaf Monkeys

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91119/1/ajp22004.pd

Infanticide and infant defence by males--modelling the conditions in primate multi-male groups

Infanticide by primate males was considered rare if groups contain more than one adult male because, owing to lower paternity certainty, a male should be less likely to benefit from infanticide. Guided by recent evidence for strong variation of infanticide in primate multi-male groups, we modelled the conditions for when infanticide should occur for a group with a resident and an immigrant male. Setting the parameters (e.g. infant mortality, reduction of interbirth interval, life-time reproductive success, genetic representation) to fit the conditions most commonly found in nature, we develop a game-theoretic model to explore the influence of age and dominance on the occurrence of infanticide and infant defence. Male age strongly impacts the likelihood of an attack which is modified by the father's defence. If the new male is dominant he is likely to attack under most circumstances whereas a subordinate male will only attack if the father does not defend. These model scenarios fit the conditions under which infanticide is known to occur in primate multi-male groups and offer an explanation why infanticide is common in some multi-male groups and rare in others. Overall, the benefits for infanticidal males are strongly governed by a reduced interbirth interval while advantages via improved genetic representation in the gene pool contribute but a minor fraction

Primate life histories and dietary adaptations: A comparison of Asian colobines and Macaques

Primate life histories are strongly influenced by both body and brain mass and are mediated by food availability and perhaps dietary adaptations. It has been suggested that folivorous primates mature and reproduce more slowly than frugivores due to lower basal metabolic rates as well as to greater degrees of arboreality, which can lower mortality and thus fecundity. However, the opposite has also been proposed: faster life histories in folivores due to a diet of abundant, protein-rich leaves. We compared two primate taxa often found in sympatry: Asian colobines (folivores, 11 species) and Asian macaques (frugivores, 12 species). We first described new data for a little-known colobine (Phayre's leaf monkeys, Trachypithecus phayrei crepusculus ) from Phu Khieo Wildlife Sanctuary, Thailand. We then compared gestation periods, ages at first birth, and interbirth intervals in colobines and macaques. We predicted that heavier species would have slower life histories, provisioned populations would have faster life histories, and folivores would have slower life histories than frugivores. We calculated general regression models using log body mass, nutritional regime, and taxon as predictor variables. Body mass and nutritional regime had the predicted effects for all three traits. We found taxonomic differences only for gestation, which was significantly longer in colobines, supporting the idea of slower fetal growth (lower maternal energy) compared to macaques and/or advanced dental or gut development. Ages at first birth and interbirth intervals were similar between taxa, perhaps due to additional factors (e.g., allomothering, dispersal). Our results emphasize the need for additional data from wild populations and for establishing whether growth data for provisioned animals (folivores in particular) are representative of wild ones. Am J Phys Anthropol, 2011. © 2010 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79432/1/21403_ftp.pd

Variation in grouping patterns, mating systems and social structure: what socio-ecological models attempt to explain

Socio-ecological models aim to predict the variation in social systems based on a limited number of ecological parameters. Since the 1960s, the original model has taken two paths: one relating to grouping patterns and mating systems and one relating to grouping patterns and female social structure. Here, we review the basic ideas specifically with regard to non-human primates, present new results and point to open questions. While most primates live in permanent groups and exhibit female defence polygyny, recent studies indicate more flexibility with cooperative male resource defence occurring repeatedly in all radiations. In contrast to other animals, the potential link between ecology and these mating systems remains, however, largely unexplored. The model of the ecology of female social structure has often been deemed successful, but has recently been criticized. We show that the predicted association of agonistic rates and despotism (directional consistency of relationships) was not supported in a comparative test. The overall variation in despotism is probably due to phylogenetic grade shifts. At the same time, it varies within clades more or less in the direction predicted by the model. This suggests that the model's utility may lie in predicting social variation within but not across clades

Beware of primate life history data: a plea for data standards and a repository.

Life history variables such as the age at first reproduction and the interval between consecutive births are measures of investment in growth and reproduction in a particular population or species. As such they allow for meaningful comparisons of the speed of growth and reproduction between species and between larger taxa. Especially in primates such life history research has far reaching implications and has led for instance to the "grandmother hypothesis". Other links have been proposed with respect to dietary adaptations: Because protein is essential for growth and one of the primary sources of protein, leaves, occurs much less seasonally than fruits, it has been predicted that folivorous primates should grow faster compared to frugivorous ones. However, when comparing folivorous Asian colobines with frugivorous Asian macaques we recently documented a longer, instead of a shorter gestation length in folivores while age at first reproduction and interbirth interval did not differ. This supports earlier findings for Malagasy lemurs in which all life history variables tested were significantly longer in folivores compared to frugivores. Wondering why these trends were not apparent sooner, we tried to reconstruct our results for Asian primates with data from four popular life history compilations. However, this attempt failed; even the basic, allometric relationship with adult female body mass that is typical for life history variables could not be recovered. This negative result hints at severe problems with data quality. Here we show that data quality can be improved significantly by standardizing the variables and by controlling for factors such as nutritional conditions or infant mortality. Ideally, in the future, revised primate life history data should be collated in a central database accessible to everybody. In the long run such an initiative should be expanded to include all mammalian species

Data from: Timing of conceptions in Phayre's leaf monkeys: energy and phytochemical intake

<p class="MsoNormal">Raising offspring imposes energetic costs, especially for female mammals. Consequently, seasons favoring high energy intake and sustained positive energy balance often result in a conception peak. Factors that may weaken this coordinated effect include premature offspring loss and adolescent subfertility. Furthermore, seasonal ingestion of phytochemicals may facilitate conception peaks. We examined these factors and potential benefits of a conception peak (infant survival, interbirth interval) in Phayre's leaf monkeys (<em>Trachypithecus phayrei crepusculus</em>). Data were collected at Phu Khieo Wildlife Sanctuary, Thailand (78 conceptions). We estimated periods of high energy intake based on fruit and young leaf feeding and via monthly energy intake rates. Phytochemical intake was based on fecal progestin. We examined seasonality (circular statistics, cox proportional hazard models) and compared consequences of timing (infant survival and interbirth intervals, t-test, Fisher exact test). Conceptions occurred in all months but peaked from May to August. This peak coincided with high fecal progestin rather than presumed positive energy balance. Primipara conceived significantly later than multipara. Neither infant survival nor interbirth intervals were related to the timing of conception. Periods of high energy intake may not exist and would not explain the conception peak in this population. However, the presumed high intake of phytochemicals was tightly linked to the conception peak. Timing conceptions to the peak season did not provide benefits, suggesting that the clustering of conceptions may be a mere by-product of phytochemical intake. To confirm this conclusion, seasonal changes in phytochemical intake and hormone levels need to be studied more directly.</p><p>Funding provided by: National Science Foundation<br>Crossref Funder Registry ID: https://ror.org/021nxhr62<br>Award Number: BCS-0215542</p><p>Funding provided by: Wenner-Gren Foundation<br>Crossref Funder Registry ID: https://ror.org/04qvvhf62<br>Award Number: 7241</p><p>Funding provided by: Leakey Foundation<br>Crossref Funder Registry ID: https://ror.org/018kdpd27<br>Award Number: </p><p>Funding provided by: American Society of Primatologists<br>Crossref Funder Registry ID: https://ror.org/04j0s0m53<br>Award Number: </p><p>Funding provided by: National Science Foundation<br>Crossref Funder Registry ID: https://ror.org/021nxhr62<br>Award Number: BCS-0452635</p><p>Funding provided by: National Science Foundation<br>Crossref Funder Registry ID: https://ror.org/021nxhr62<br>Award Number: BCS-0542035</p><p>Funding provided by: National Science Foundation<br>Crossref Funder Registry ID: https://ror.org/021nxhr62<br>Award Number: BCS-0647837</p><p>Funding provided by: Wenner-Gren Foundation<br>Crossref Funder Registry ID: https://ror.org/04qvvhf62<br>Award Number: 7639</p><p class="MsoNormal">The data were observational in nature. Of the 78 total conceptions used in the analyses, 71 were based on the day of detection of a newborn in the study groups from which the mean gestation length (205 days) was subtracted to find the conception date. The 7 additional conceptions were determined via hormone analysis of fecal material (Lu, Borries, Czekala & Beehner, 2010).</p> <p class="EndNoteBibliography">Lu, A., Borries, C., Czekala, N. M., & Beehner, J. C. (2010). Reproductive characteristics of wild female Phayre's leaf monkeys. <em>American Journal of Primatology</em>, <strong>72</strong>, 1073-1081. <a href="https://doi.org/10.1002/ajp.20866">https://doi.org/10.1002/ajp.20866</a>.</p&gt