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Sperm Collection of Differential Quality Using Density Gradient Centrifugation
Published on: November 29, 2018
Phenotypic quality influences fertility in Gombe chimpanzees
James Holland Jones1, Michael L Wilson, Carson Murray
1Department of Anthropology, Stanford University, 450 Serra Mall, Bldg. 50, Stanford, CA 94305-2034, USA. jhj1@stanford.edu
The Journal of Animal Ecology
|April 24, 2010
Summary
Measuring chimpanzee fertility is challenging. Infant loss significantly increases birth rates, while maternal age and dominance rank also influence birth intervals in wild chimpanzees.
Area of Science:
- Primate reproductive ecology
- Behavioral ecology
- Primatology
Background:
- Fertility is a key fitness component but difficult to quantify in long-lived, slow-reproducing species like chimpanzees (Pan troglodytes).
- Understanding factors influencing birth intervals is crucial for population dynamics and conservation efforts.
Purpose of the Study:
- To measure fertility in wild chimpanzees and assess the impact of covariates on birth intervals.
- To investigate the influence of maternal age, infant survival, birth order, dominance rank, and individual heterogeneity on chimpanzee reproductive timing.
Main Methods:
- Utilized a 43-year dataset of chimpanzee birth intervals from Gombe National Park, Tanzania.
- Employed Cox proportional hazards regression with individual-level random effects to analyze fertility data.
- Examined covariates including maternal age, infant loss, birth interval number, infant sex, and maternal dominance rank.
Main Results:
- Birth hazard decreased with maternal age (0.84 per year post-first reproduction).
- Infant loss increased birth hazard 134-fold; subsequent birth intervals were shorter than the first.
- Maternal dominance rank (high vs. others) and individual heterogeneity significantly impacted birth interval duration.
Conclusions:
- Individual heterogeneity in birth interval duration may reflect phenotypic quality, correlating with body mass.
- Maternal age, infant survival, and dominance rank are critical factors modulating chimpanzee reproductive patterns.
- This study provides valuable insights into the complex drivers of fertility in a long-lived primate species.
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