Projects / Programmes
Evolutionary tests of primate sociality models
| Code |
Science |
Field |
Subfield |
| 1.03.00 |
Natural sciences and mathematics |
Biology |
|
| Code |
Science |
Field |
| B460 |
Biomedical sciences |
Physical anthropology |
Social evolution, cross-species comparisons, primates, demography, socioecological model, phylogenetic tests
Researchers (1)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
34712 |
PhD Mojca Stojan Dolar |
Interdisciplinary research |
Head |
2014 - 2016 |
71 |
Organisations (1)
Abstract
The question of why animals live in groups is one of the central topics in behavioural ecology. Primates provide an interesting model to study the evolution of sociality as they exhibit a high diversity of social systems. Understanding how this diversity evolved illuminates the selective forces at work, which has implications also for other vertebrates and may ultimately help to better understand the evolutionary drivers of human sociality.
To explain the evolution of sociality in primates, primatologists generally make use of the “socioecological model” (SEM), which emphasizes predation risk and the abundance and distribution of resources as the key parameters explaining primate sociality. These factors define the spatial distribution of females (whose fitness largely depends on access to food), which in turn defines the number of males (whose fitness largely depends on mating opportunities) in primate groups. Based on these basic mechanisms, the model aims to predict the size, composition, social relationships, patterns of dispersal or philopatry, and kin structure of a group.
A number of studies tested predictions derived from SEM in a variety of primate species and the results often confirm the predictions, but with notable exceptions that are poorly explained by the model. Recently, many aspects of the model have been criticized, raising conceptual and methodological concerns and debating a number of potentially important but so far overlooked factors. In short, the SEM (1) leaves much of the variation of primate social systems unexplained (2) neglects the importance of phylogenetic constraints and (3) relies on purely verbal argumentation instead of mathematical models.
A first approach to set the basis for a mathematical framework of primate sociality has recently been developed by my collaborator Markus Port of Cambridge University and his colleagues. They have recognized that some of the same life-history and demographic factors promoting the evolution of sociality in cooperatively breeding birds and mammals may also be responsible for shaping primate social evolution. They adopt a demographically explicit approach in which the rates of births and deaths as well as the dispersal decisions of individuals in the population determine the degree of habitat saturation, and hence, the competition for territories. Variation in vital rates such as fecundity and mortality has so far been ignored as determinants of primate social evolution. The new models therefore represent a genuinely novel approach to modelling primate sociality and have the potential to explain variation in primate social systems that the SEM cannot explain.
The proposed project aims to address the above described issues by employing cross-species comparative methods to test (1) the predictions derived from the SEM and (2) the predictions of the new mathematical framework. Relevant data on as many primate species as possible will be drawn from the existing primate literature. I will test the predictions using phylogenetic tests based on the newest primate phylogeny. The results will help to illuminate the strengths and weaknesses of the current verbal model but also to critically evaluate the relevance of the recently developed mathematical model. Ultimately, the project hopes to contribute to a better understanding of how the diversity of primate social systems evolved and thus illuminate the selective forces at work, which has implications also for other vertebrates and may eventually contribute to a better understanding of the evolutionary drivers of human sociality.
Note: The software does not allow me to fully control italics and font size. I therefore appologize for the non-consistent text formating.
Significance for science
The most important results of the project will be two relational databases with primatological data: one with life history data and one with data on group sizes and compositions. They will provide the basis for a number of scientific discussions and we hope that they will be of use for researchers from various fields - anthropology, biology, evolution and paleobiology. Both types of data have broad implications. Interspecies comparisons based on quality input data provide a wider understanding of evolutionary mechanisms and can help us understand the unique characteristics of our own species. Life history data are measures of investment in growth and reproduction in a particular population or species. As such they provide the basis for interspecies comparison of growth and reproductive strategies, they allow for reconstruction of life history traits of extinct species and contribute to the understanding of the evolution of human life history, which is characterized by slow growth, high birth rate and very slow aging. Data on group size and composition plays a key role in primate behavioral ecology, it is needed in the analyses that attempt to explain the evolution of sociality and provide the basis for one of the explanations of the evolution of large brains in primates. In this context, the first appropriately designed and equipped databases are of great importance. We followed the principles proposed as good practice guidelines for scientific databases (Borries et al. 2016), which distinguish our databases from the existing compilations: 1. Defining and Describing Data. All parameters are precisely described and defined. All entries in the database are double-checked. We selected only reliable data points and eliminated the values that were described as rough estimates in the original source. 2. Tagging Data with Metadata. Data are equipped with the necessary metadata such as sample size, the original source, location where the measurements were made, whether the animals were additionally fed, habitat quality, duration of observation, definitions of age classes, and other data that further specify each variable of (e. g. offspring survival for inter-birth intervals or the method of determining the time of conception for the duration of gestation). This way, the information on the variability within the species is retained in the database and distinguishing between different phenomena is possible. 3. Documenting Procedures. We recorded the procedures of search strategies used to locate the data. All data were drawn from original sources and not from assembly articles as to avoid the accumulation of errors and neglect of recent studies. 4. Facilitating Effective Interactions with the Data. Data will be published in various formats and available to a wide audience. I also pointed to the methodological problems associated with measuring predation pressure. Predation is perceived as one of the key factors in the evolution of sociality and plays an important role also in the evolution of other behavioral and morphological characteristics of species. However, it is very difficult to measure in nature, which led some researchers to use body mass and terrestriality as proxy measures. Based on my results I suggest such indirect measures should be used with great caution. Instead, it may be better to record several direct measures of predation that try to measure the same phenomenon with different approaches. Borries, C., Sandel, A. A., Koenig, A., Fernandez-Duque, E., Kamilar, J. M., Amoroso, C. R., et al. (2016). Transparency, usability, and reproducibility: Guiding principles for improving comparative databases using primates as examples. Evolutionary Anthropology, 25(5), 232–238. doi:10.1002/evan.21502
Significance for the country
Primatology and behavioral ecology are important and well-developed fields of biology, but are underrepresented in Slovenian science. This project opened new topics and perspectives in Slovenian biology in collaboration with internationally renowned scientists and institutions. I presented the results at the joint meeting of International Primatological Society and American Society of Primatologists in Chicago, where I was the only delegate from Slovenia. I try to promote better understanding of primates, which are our closest relatives, among the general public. I collaborate with Kino Dvor, where I have discussions with schoolchildren when screenings of primate-related films for schools are organized. I presented many primatological topics to Slovenian students of biology, archeology and pedagogy within university courses on human biology and paleoanthropology. The project provided an opportunity for four talented young people to gain practical experience with examining scientific literature. While working on the database, they learnt to extract relevant information from technical texts and gained the ability to critically assess different scientific publications.
Most important scientific results
Final report
Most important socioeconomically and culturally relevant results
Final report
