Female chacma baboons modulate their sexual receptivity in response to male intrasexual competition
Data files
Nov 21, 2023 version files 45.24 KB
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Baboons_complete.xlsx
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Darmis_et_al._code.R
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README.md
Abstract
Research in social mammals has revealed the complexity of strategies females use in response to female-female reproductive competition and sexual conflict. One point at which competition and conflict manifest acutely is during sexual receptivity, indicated by swellings in some primates. Whether females can adjust their sexual receptivity from cycle to cycle to decrease reproductive competition and sexual conflict in response to social pressures has not been tested. As a first step, this study explores whether sexual receptivity duration is predicted social pressures in wild female chacma baboons (Papio ursinus). Given that female baboons face intense reproductive competition and sexual coercion, we predicted that: females could shorten the duration of their sexual receptive period to reduce female-female aggression and male coercion or increase it to access multiple or their preferred male(s). We quantified 157 ovulatory cycles from 46 wild females living in central Namibia recorded over 15 years. We found no support for our hypothesis; however, our analyses revealed a negative correlation between maximal-swelling duration and group size, a proxy of within-group competition. This study provides further evidence that swelling is costly as well as a testable framework for future investigations of ‘cycle length manipulation’.
README
This readme file was generated on 27/08/2023 by Fragkiskos Darmis
GENERAL INFORMATION
Title of Dataset: Baboons_complete
Author
Name: Fragkiskos Darmis
ORCID: 0000-0002-1457-676X
Institution: Max Planck Institute for Evolutionary Biology
Address: August-Thienemann-Straße 2, 24306 Plön
Email: darmis@evolbio.mpg.de
Author
Name: Alecia J. Carter
ORCID: 0000-0001-5550-9312
Institution: University College London
Address: 14 Taviton Street Kings Cross, WC1H 0BW, London
Email: alecia.carter@ucl.ac.uk
Author
Name: Élise Huchard
ORCID: 0000-0002-6944-449X
Institution: Institut des Sciences de L'Evolution de Montpellier, UMR 5554, CNRS, Université de Montpellier
Address: 1093-1317 Rte de Mende, 34090, Montpellier
Email: elise.huchard@umontpellier.fr
Author
Name: Guy Cowlishaw
ORCID: 0000-0002-7269-4625
Institution: Institute of Zoology, Zoological Society of London
Address: Zoological Society of London, Regent's Park, NW14RY
Email: guy.cowlishaw@ioz.ac.uk
Date of data collection: 2005-2019
Geographic location of data collection: Tsaobis Leopard Park (22º22´S, 15º 44´E) in central Namibia
Information about funding sources that supported the collection of the data:
Long-term data collection was partially funded by grants from: the Agence Nationale de la Recherche (ANR ERS-17-CE02-0008, 2018-2021) awarded to EH; a Fenner School of Environment and Society Scholarship awarded to A.J.C., a Ministère de l’Education et de la Recherche Studentship awarded to E.H; a NERC Advanced Research Fellowship awarded to G.C.; Leakey Foundation grants awarded to AJC; and a Templeton World Charity Foundation grant (TWCF0502) awarded to AJC. This paper is a contribution ISEM (n° TBD) and a publication of the ZSL Institute of Zoology’s Tsaobis Baboon Project, supported by Research England.
SHARING/ACCESS INFORMATION
Licenses/restrictions placed on the data: -
Links to publications that cite or use the data: -
Links to other publicly accessible locations of the data: -
Links/relationships to ancillary data sets: -
Was data derived from another source?
If yes, list source(s): -
Recommended citation for this dataset: Baboons_complete
DATA & FILE OVERVIEW
File List: Baboons_complete
Relationship between files, if important: -
Additional related data collected that was not included in the current data package: -
Are there multiple versions of the dataset?
If yes, name of file(s) that was updated: -
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METHODOLOGICAL INFORMATION
Description of methods used for collection/generation of data:
Data were collected from identifiable females within two habituated groups, J and L, of a wild chacma baboon population at Tsaobis Leopard Park (22º22´S, 15º 44´E) in central Namibia. Studies on this population, which have been ongoing since 2000, have revealed that the naturally-foraging baboons exhibit low predation risk and high female-female aggression rates that can result in reproductive suppression. Over the course of the study, troop numbers fluctuated around a median of 55 (44–69) in J troop and 52 (21–71) in L troop.
The data used in this study were collected periodically over 15 years, from 2005 to 2019, during field seasons lasting between 2 and 8 months per annum, usually during the austral winter. During field seasons, troops were visited daily, when possible, with some interruptions for other tasks or unforeseen circumstances. During troop visits, we collected data on troop composition (see below) and individual behaviour ad libitum.
Individuals’ ages were known from observing births or from patterns of dentition wear following capture. Individuals’ relative ranks were calculated annually from ad libitum recorded dominance interactions in the package Matman 1.1.4 (Noldus Information Technology, 2013). Absolute ranks were converted to a relative scale ranging from 0 (lowest rank) to 1 (highest rank), to control for group size, using the formula 1-((1-r)/(1-n)), with r being individual’s absolute rank ranging from 1 to the total group size n.
Methods for processing the data:
Each day that the troop was contacted, a census was completed that recorded the identities of the individuals present and the reproductive states of each adult female. Females’ reproductive states were recorded as: (1) pregnant (determined post hoc based on lack of resumption of swelling, reddening of the paracallosal skin and subsequent birth); (2) lactating (i.e., period following the birth of an infant until cycle resumption); (3) oestrous/swollen (i.e., exhibiting periovulatory swelling of the anogenital region); (4) non-swollen (i.e., deturgescent but not pregnant). For females in oestrus, we also recorded swelling size on a scale from 0.5 (smallest)-4 (largest), on an absolute (cf. the population) rather than relative (cf. for that particular female) scale. As mentioned above, baboon troops were not followed daily, and as such there were some missing data during some females’ cycles. We discarded any observations where the start or end of the swelling duration was missing and thus could introduce inaccuracy.
For females in oestrus, swelling duration was calculated as the number of continuous days that a female was recorded with a swelling of any size. Because different mechanisms could act on the different parts of the cycle, in addition to swelling durations, we calculated the maximal-swelling duration as the number of days the focal female exhibited the largest swelling size during that respective cycle. We excluded from the initial data 8 observations of maximal-swelling duration which were calculated as 0, i.e., observations that showed that females were only swollen, and this resulted in 158 swellings and 158 maximal-swellings from 47 females (median number of swellings / female = 5, range = 1-14).
We calculated five variables describing aspects of the social environment relevant to our hypotheses: for H1 we calculated (1) the sum of pregnant and lactating females (“PL”) during the time a focal female was either swollen or maximally-swollen. For hypothesis H2a, we measured the number of other females that were (2) not maximally-swollen and (3) maximally-swollen, both when the focal female started swelling. To test hypothesis H2b and part of H2c, we calculated the (4) operational sex ratio (“OSR”) as the ratio of sexually active females (i.e., swollen at any level) to adult males. For H2c, we also calculated the (5) the number of in-group adult males.
We have also calculated group size, the number of adults and subadults in each troop, to test if
Instrument- or software-specific information needed to interpret the data:
All statistical analyses were performed using R (version 4.0.3, 2020-10-10). Repeatability (R) was calculated using the rpt function (rptR package),
Standards and calibration information, if appropriate: -
Environmental/experimental conditions: -
Describe any quality-assurance procedures performed on the data: -
People involved with sample collection, processing, analysis and/or submission:
Past Tsaobis Baboon Project leaders, students, volunteers and interns contributed to the long-term data collection at the field site.
AJC, EH and FD contributed to the conceptualization. AJC and EH designed the study. GC established the study system and oversaw data collection, with assistance from AJC and EH. FD performed the statistical analyses. All authors contributed to draft the manuscript.
DATA-SPECIFIC INFORMATION FOR: Baboons_complete
Number of variables: 18
Number of cases/rows: 158
Variable List:
- ID: The individual ID of a female, here a number is used to indicate it.
- troop: The troop to which a female belonged during the observation, with three troops being recorded (M, J, L).
- so_date: The date the focal female started swelling.
- state: The size of the swelling at the start of the swelling period.
- mxm_sw_dur: The number of days the focal oestrous female exhibited the largest swelling size during that respective cycle.
- sw_dur: For females in oestrus, swelling duration was calculated as the number of continuous days that a female was recorded with a swelling of any size.
- not_mxm_sw_fem: The number of other females that were not maximally-swollen when the focal female started swelling.
- mxm_sw_fem: The number of other females that were maximally-swollen when the focal female started swelling.
- p_females: The number of pregnant females during the time a focal female was either swollen or maximally-swollen.
- l_females: The number of lactating females during the time a focal female was either swollen or maximally-swollen.
- p_l: The sum of pregnant and lactating females during the time a focal female was either swollen or maximally-swollen.
- cycling_females: The number of females that were cycling (i.e., not pregnant or lactating) but not swollen.
- group_size: The total number of individuals of any age in the troop.
- adult_males: The number of adult males in the troop of the focal female during the time of observation.
- age: The age of the focal female, measured in years.
- relative_rank: The relative rank of the focal female compared to other females of the troop at the time of observation. The relative scale ranged from 0 (lowest rank) to 1 (highest rank), and was created using the formula 1-((1-r)/(1-n)), with r being individual’s absolute rank ranging from 1 to the total group size n.
- sw_females: The number of other females that were swollen at any stage (maximally and non-maximally) when the focal female started swelling.
- OSR_(f/m): The number of sexually receptive females to the number of adult males.
Missing data codes: NA (data not available / not applicable)
Specialized formats or other abbreviations used: -
Methods
Data were collected from identifiable females within two habituated groups, J and L, of a wild chacma baboon population at Tsaobis Leopard Park (22º22´S, 15º 44´E) in central Namibia. Studies on this population, which have been ongoing since 2000, have revealed that the naturally-foraging baboons exhibit low predation risk and high female-female aggression rates that can result in reproductive suppression. Over the course of the study, troop numbers fluctuated around a median of 55 (44–69) in J troop and 52 (21–71) in L troop.
The data used in this study were collected periodically over 15 years, from 2005 to 2019, during field seasons lasting between 2 and 8 months per annum, usually during the austral winter. During field seasons, troops were visited daily, when possible, with some interruptions for other tasks or unforeseen circumstances. During troop visits, we collected data on troop composition (see below) and individual behaviour ad libitum.
Individuals’ ages were known from observing births or from patterns of dentition wear following capture. Individuals’ relative ranks were calculated annually from ad libitum recorded dominance interactions in the package Matman 1.1.4 (Noldus Information Technology, 2013). Absolute ranks were converted to a relative scale ranging from 0 (lowest rank) to 1 (highest rank), to control for group size, using the formula 1-((1-r)/(1-n)), with r being individual’s absolute rank ranging from 1 to the total group size n.
Methods for processing the data:
Each day that the troop was contacted, a census was completed that recorded the identities of the individuals present and the reproductive states of each adult female. Females’ reproductive states were recorded as: (1) pregnant (determined post hoc based on lack of resumption of swelling, reddening of the paracallosal skin and subsequent birth); (2) lactating (i.e., period following the birth of an infant until cycle resumption); (3) oestrous/swollen (i.e., exhibiting periovulatory swelling of the anogenital region); (4) non-swollen (i.e., deturgescent but not pregnant). For females in oestrus, we also recorded swelling size on a scale from 0.5 (smallest) to 4 (largest), on an absolute (cf. the population) rather than relative (cf. for that particular female) scale. As mentioned above, baboon troops were not followed daily, and as such there were some missing data during some females’ cycles. We discarded any observations where the start or end of the swelling duration was missing and thus could introduce inaccuracy.
For females in oestrus, swelling duration was calculated as the number of continuous days that a female was recorded with a swelling of any size. Because different mechanisms could act on the different parts of the cycle, in addition to swelling durations, we calculated the maximal-swelling duration as the number of days the focal female exhibited the largest swelling size during that respective cycle. We excluded from the initial data 8 observations of maximal-swelling duration which were calculated as 0, i.e., observations that showed that females were only swollen, and this resulted in 158 swellings and 158 maximal-swellings from 47 females (median number of swellings / female = 5, range = 1-14).
We calculated five variables describing aspects of the social environment relevant to our hypotheses: for H1, we calculated (1) the sum of pregnant and lactating females (“PL”) during the time a focal female was either swollen or maximally-swollen. For hypothesis H2a, we measured the number of other females that were (2) not maximally-swollen and (3) maximally-swollen, both when the focal female started swelling. To test hypothesis H2b and part of H2c, we calculated the (4) operational sex ratio (“OSR”) as the ratio of sexually active females (i.e., swollen at any level) to adult males. For H2c, we also calculated the (5) the number of in-group adult males.
Usage notes
All statistical analyses were performed using R (version 4.0.3, 2020-10-10). Repeatability (R) was calculated using the rpt function (rptR package).