ELECTRONIC SUPPLEMENTARY MATERIAL
PRIMATES
Seed predation by bonobos (Pan paniscus) at Kokolopori,
Democratic Republic of the Congo
Georgiev, A.V., Emery Thompson, M., Lokasola, A.L. & Wrangham, R.W.
METHODS: SUPPLEMENTARY INFORMATION
Data Collection
Party composition & feeding locations
For assessing party membership, we defined all individuals travelling within 50 m of each other or arriving at the same feeding location within 15 min of each other as members of the same party. We defined feeding locations in the following manner. An arboreal feeding location was a single tree; two or more trees with adjacent crowns allowing continuous feeding; or a grove of trees each of which was within 50 m of each other and in which bonobos were feeding concurrently. A terrestrial feeding location was the area under a tree crown; under adjacent crowns; or under the crowns of trees within the same grove (for items such as seeds that fell from trees); or as a patch of herbs separated by less than 50 meters from neighbouring patches.
Urine Sampling and Analysis
We collected urine samples at dawn when bonobos urinated from their nests. We sampled from midstream using a 1-2 m long stick with an attached disposable plastic bag at the end whenever possible, and when not, we pipetted urine off vegetation if it was certain that only one individual urinated in that place. Collecting chimpanzee urine from the forest foliage in this manner does not affect results of hormonal analyses (Muller and Wrangham 2004). We stored urine samples on filter paper within 24 hrs of collection (usually within 12 hrs), following the protocol described by Knott (1997). We kept urine samples in airtight containers with silica gel for up to 3 months in the field, and then in a freezer (-20°C) at the Primate Reproductive Ecology Laboratory at Harvard University. A.V.G. and M.E.T. carried out the subsequent hormonal analysis at the same facility, with each set of samples assayed approximately 6 months after collection. We assayed urinary C-peptide with commercially-available radioimmunoassay kits (DSL Labs, Webster, TX) following previously-described protocols (Sherry and Ellison 2007; Emery Thompson and Knott 2008; Emery Thompson et al. 2009). Intra-assay coefficients of variation (CV) for replicated filter paper samples were 11.8% and 6.9% for low and high samples, respectively, and inter-assay CVs were 4.1% and 11.1%. C. Munro at the University of California, Davis provided enzyme-immunoassay reagents for cortisol assays. Cortisol protocols followed Muller et al. (2007) and Kahlenberg et al. (2008). Intra-assay CVs were 5.4 and 9.5% for low and high samples, respectively, and inter-assay CVs were 13.3% and 9.6%. Assay sensitivities were approximately 10 pg/ml for C-peptide and 300 pg/ml for cortisol. We standardized all hormonal values for concentration by using creatinine measurements. While cortisol shows circadian variation in secretion (Muller and Lipson 2003; Anestis and Bribiescas 2004), there was no need to time-adjust the cortisol values because all urine samples for this study were first-morning voids collected within a narrow time-window (5:00 – 6:20 am).
SUPPLEMENTARY REFERENCES
Anestis SF, Bribiescas R (2004) Rapid changes in chimpanzee (Pan troglodytes) urinary cortisol excretion. Horm Behav 45:209-213
Emery Thompson M, Knott CD (2008) Urinary C-peptide of insulin as a non-invasive marker of energy balance in wild orangutans. Horm Behav 53:526-535
Emery Thompson M, Muller MN, Wrangham RW, Lwanga JS, Potts KB (2009) Urinary C-peptide tracks seasonal and individual variation in energy balance in wild chimpanzees. Horm Behav 55:299-305
Kahlenberg SM, Thompson ME, Muller MN, Wrangham RW (2008) Immigration costs for female chimpanzees and male protection as an immigrant counterstrategy to intrasexual aggression. Anim Behav 76:1497-1509
Knott CD (1997) Field collection and preservation of urine in orangutans and chimpanzees. Trop Biodiv 4:95-102
Muller M, Lipson S (2003) Diurnal patterns of urinary steroid excretion in wild chimpanzees. Am J Primatol 60:161-166
Muller M, Wrangham RW (2004) Dominance, cortisol and stress in wild chimpanzees (Pan troglodytes schweinfurthii). Behav Ecol Sociobiol 55:332-340
Muller M, Kahlenberg S, Emery Thompson M, Wrangham R (2007) Male coercion and the costs of promiscuous mating for female chimpanzees. P Roy Soc B –Biol Sci 274:1009-1014
Sherry DS, Ellison PE (2007) Potential applications of urinary C-peptide of insulin for comparative energetics research. Am J Phys Anthropol 133:771-778
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