Data from: Interbirth intervals in wild baboons: environmental predictors and hormonal correlates
Gesquiere, Laurence R., Duke University
Altmann, Jeanne, Princeton University, Institute of Primate Research
Archie, Elizabeth A., Notre Dame University, University of Notre Dame, Institute of Primate Research
Alberts, Susan C., Duke University, Institute of Primate Research
Published Jan 10, 2019 on Dryad.
Cite this dataset
Gesquiere, Laurence R.; Altmann, Jeanne; Archie, Elizabeth A.; Alberts, Susan C. (2019). Data from: Interbirth intervals in wild baboons: environmental predictors and hormonal correlates [Dataset]. Dryad. https://doi.org/10.5061/dryad.gd788
Objectives: Interbirth intervals (IBIs) are a key metric of female reproductive success; understanding how they are regulated by environmental, social, and demographic factors can provide insight into sources of variance in female fitness. Materials and Methods: Using 36 years of reproductive data on 490 IBIs for 160 wild female baboons, we identified sources of variance in the duration of IBIs and of their component phases: postpartum amenorrhea (PPA), sexual cycling, and pregnancy. We also examined how body fat and fecal hormone concentrations varied during female IBI.
Results: We found that IBIs tended to be shorter (reproduction was accelerated) when female traits and environmental variables promoted energy acquisition, but with different specific effects for different component phases of the IBI. We also found that females lost a substantial amount of body fat during PPA, indicating that PPA imposes accumulating energetic costs as it progresses. Prior to cycle resumption females began to regain body fat; body fat was stable across the cycling phase and increased throughout most of pregnancy. However, body fat scores per se were not associated with the duration of any of the component phases. Finally, we found that fecal glucocorticoid concentrations decreased as PPA progressed, suggesting a decline in energetic stress over this phase. Fecal progestogen and estrogen concentrations changed over time during sexual cycling; the direction of these changes depended on the phase of the sexual cycle (luteal versus early or late follicular phases). Discussion: Our study lends insight into the energetic constraints on female primate reproduction, revealing how female environments, changes in body fat, and steroid hormone concentrations relate to IBI duration and to reproductive readiness.
This dataset was used to conduct our first analysis, which examined the duration of IBIs and their component phases. For this analysis we used 36 years of data (collected between 1977 and 2012) on reproductive states, demographic events, dominance rank, and rainfall for 160 wild-feeding females. Specifically, we had a total of 490 IBIs for 160 females that fit our analysis criteria (see Methods - Data Analysis), with each female contributing an average of 3 IBIs to the dataset (range: 1-10).
Note that female identity and pregnancy identity have been anonymized and the ID given were identical across tables.
This dataset included the body fat scores, which were used to conduct our second analysis. For this analysis, we had 345 body fat scores for 105 females during 260 IBIs (collected between 2008 and 2014). Scores were collected during July, August, or November of each year, and the timing of the score within the IBI varied across females. 183 fat scores were assessed during PPA, 70 during cycling, and 92 during pregnancy. For any given phase of a given IBI, females were usually assessed once, but in a few cases females were assessed twice during a given PPA (n=11). For these 11 cases an average body fat score was calculated so that each female contributed only one score for each PPA.
This dataset includes the data for our third analysis, which examined fecal glucocorticoids (fGC), fecal estrogens (fE), and fecal progestogens (fP) during PPA as a function of the number of months to sexual cycle resumption, or during the various phases of the sexual cycles (early or late follicular and luteal) as a function of the number of cycles to conception. For fGC and fE we had a total of 5,470 hormone samples collected between 2000 and 2014 for 138 females during 549 IBIs. Of these samples, 4,150 fecal samples were collected during PPA, and 1,320 were collected during cycling. Each female contributed fecal samples from an average of 4 IBIs (range: 1-11) with an average of 10 hormone samples per IBI (range: 1-55) and an average total number of 40 samples per female (range: 1-145). For fP, we had a smaller sample size of 4,095 hormone samples collected between 2003 and 2014 for 130 females during 456 IBIs; 2,922 were collected during PPA and 1,173 during cycling. Each female contributed samples from an average of 3.5 IBIs (range 1-8), with an average of 9 (range 1-47) samples per IBI, for an average total number of 32 (range 1-141) samples per female.
National Science Foundation, Award: BCS 0323553, BCS 0323596, IBN 0322613, IBN 0322781, DEB-0846286, DEB-0846532, DEB 0846286, DEB-0919200, IOS-0919200, IOS 1053461, IOS 1456832