intestine whilst the RIVM model used 2 hours for both. The modification to reflect the Ateles transit times were mixing with saliva fluid of 3 mins followed by 60 mins after addition of the gastric media.
o NaSCN Sodium thiocyanate - is secreted as an anti-oxidant in saliva, was not added to the Ateles fluids, due to COSHH regulations.
o mucin and pepsin in gastric media - levels were reduced by ~ 20%, to reflect the reduced time available for secretion in Ateles associated with a reduced transit time and differences in volume/scale of the stomach and intestine.
2.3.5 Model Schematic
The schematic diagram of the ad hoc Ateles model is shown in Figure 2.2, which is based on the modified DIN 17938 /Swallow-fasted model of Brandon et al. (2006).
2.3.5.1 Sample Size
Upon drying both the Viscum album (used in method development) and Phoradendron, (Section 4.2), showed a loss of approx. 55-65%, thus the 2.5g of dried leaf sample would represent ~5g wet leaf mass. This would equate to > 20 leaves depending upon the species of Phoradendron. In order to maximise the number of possible analyses the above schematic was reduced to use 500mg leaf and/or 200mg geophagy sample, 2ml saliva and 6ml gastric media. This permitted replicate analyses to be performed. 15ml polypropylene centrifuge tubes were used for the digestions; this reduced the residual volume of air in the tubes whist permitting adequate mixing.
Figure 2.2 Schematic showing the parameters of the ad hoc Ateles Model.
Chopped leaf 2.5g and/or 1g geophagy sample
Add 10 ml Salivary Juice Mix 3 mins at 370C
Add 30 ml Gastric Juice adjusted to pH 2 Mix for 60 mins at 370C
Centrifuge/filter Remove supernatant
Store at 40C until analysis or freeze dry
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Chapter 3 Analysis of Geophagic Samples
3.1 Introduction
This chapter relates to Specific Aim 1(Section 1.11) to characterise the geophagic material and relate the analytical results to the probable functions hypothesised for geophagy (Section 1.9). Briefly the hypotheses are classified: 1) Adaptive Beneficial e.g. protection from toxins such as plant secondary metabolites or bacterial toxins and pathogenic organisms; providing mineral or micronutrients; alleviating symptoms such as diarrhoea or excess acid or as 2) A Non-adaptive aberrant behaviour. The latter is unlikely to be addressed by physico-chemical analyses.
Table 3.1 Examples of post 1999 primate/geophagy publications.
Species Reference Site
chacma baboons Papio cynocephalus ursinus
Pebsworth et al. (2012, 2013) South Africa
bonobo Pan paniscus Beaune et al. (2013) D. R. Congo
chimpanzee Pan troglodytes
schweinfurthii
Aufreiter et al. (2001), Ketch et al.(2001)
Tanzania and Gombe
chimpanzee Pan troglodytes
schweinfurthii
Mahaney et al. (2005) Uganda red howler monkeys Alouatta seniculus Blake et al. (2010) E. Ecuador red handed howler monkey Alouatta belzebul de Souza et al. (2002) E. Brazil Phayre's leaf monkeys Trachypithecus phayrei Pages et al. (2005) Thailand golden bamboo lemur Hapalemur aureus Jeannoda et al. (2003) Madagascar
bonnet macaques Macaca radiata Voros et al. (2001) India
Japanese macaques Macaca fuscata Wakibara et al. (2001) Japan
orangutans Pongo pygmaeus. Matsubayashi et al. (2007, 2011) Sabah, Borneo bearded Saki monkey Chiropotes satanas Veiga et al. (2007) S. E. Brazil bald-faced Saki monkeys Pithecia irrorata Adams et al. (2011) Peru Milne-Edwards' sifaka Propithecus edwardsi Arrigo-Nelson et al. (2010) Madagascar white-bellied Spider monkeys Ateles belzebuth Blake et al. (2010) E. Ecuador
brown spider monkey Ateles hybridus Link et al. (2011a) Columbia
Geophagy in animals has increasingly been reported, resulting in many more species being identified as exhibiting this behaviour e.g. with the first instance of a geophagy in a marsupial, the eastern grey kangaroo (Macropus giganteus) being reported (Best et al. 2013). The potential importance of geophagy was highlighted in a doctoral thesis (Montenegro 2004) which suggested that salt/mineral licks should be classed as a Keystone Resource for both humans and animals. A keystone resource is one "whose impact on its community or ecosystem is large and disproportionately large relative to its abundance" (Power 1996 in Watson 2001).
There have also been many publications relating to human geophagy attempting to determine the function of geophagy e.g. (Henry et al. 2003, Abrahams et al. 2006, Kawai et al. 2009, Young et al. 2010, Young et al.
2011, Abrahams et al. 2013). The publications, prior to 1999, specifically relating to geophagy in primates were collated and reviewed (Krishnamani et al. 2000). Since then there have been further publications, e.g. those in Table 3.1. Ferrari et al. (2008) reviewed those specific to New World primates.
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3.2 Santa Rosa Primary Geology and Volcanic history
Figure 3.1 shows the underlying morphology of the Santa Elena peninsula and the tectonic features of the area. The Santa Elena Nappe is an overthrust of allochthonous material composed of a) ultramafic complex derived from mid ocean ridge basalts and b) mafic material which has a signature suggestive of island arc origin with low-grade metamorphism and hydrothermal alteration. (Glossary of Geological terminology Appendix 1.2).
Figure 3.1 Geological map of the Santa Elena Peninsula modified from Gazel et al. (2006)
The Santa Elena Accretionary Complex is an autochthonous basaltic sedimentary suite, resting immediately below the overthrust. This includes pelagic and volcanoclastic sediments, tuffs and magmatic rocks. The known geophagy sample sites are close to the E-W fault adjacent to the Santa Elena Accretionary Complex, (Figure 3.1). This is exposed within the tectonic-erosional window at Río Potrero Grande. This unit includes pillow lavas and radiolarian cherts i.e. sedimentary rocks with high silica content (Gazel et al. 2006).
The Santa Rosa plateau occupies an area of approximately 1500 Km2 between the Pacific coast to the West and the Cordillera de Guanacaste which includes the stratovulcanic complex of Rincón de la Vieja to the east (10049’48”N 850 19’26”W). The vulcanology of the area (Kempter 1997) contributes to the secondary geology of the research area as the sedimentary rocks are covered by the ignimbrites of Santa Rosa plateau (Chiesa et al. 1987, Chiesa et al. 1992, Vogel et al. 2004).
Large volumes of these silicic ignimbrites, with an estimated volume of 130 cu km, are found in central and northern Costa Rica, extending from the border with Nicaragua to the city of Cañas (Mora 1988). The geological map of Guanacaste (Figure 3.2) shows the extent of the ignimbrites (Orange area) which contains the study area. These ignimbrites originate from large explosions of ancient volcanic sources, probably located below the current volcanic cordillera de Guanacaste. Some of these flows extended 40-50 km from the point of eruption. Between the levels of ignimbrites are small continental sedimentary deposits called epiclastitic units.
The Santa Rosa plateau thus consists of a sequence of several deposits of pyroclastic flows, and ignimbrites, deposits of pumice and pyroclastic material, interspersed with fluvio-lacustrine sediments and some andesitic lava (Chiesa 1991).
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Figure 3.2 Geological map showing the extent of the ignimbrites with reference to the study area and a geological profile, modified from (Chiesa et al. 1987).
3.3 Methods
Mahaney et al. (2003) provide a framework for both the collection of samples, identification of potential control sites and the range of analyses, attempting to standardise data collected and so permitting improved comparisons with other publications.
3.3.1 Geophagy Sample Area Description
The known Ateles geophagy sites were situated along the edge of the mesa (Figure 3.3). The top of the mesa is heavily wooded with a mixture of mature trees and understorey vegetation (Figures 3.3-3.4). The top is also relatively flat; there is no gradual slope away from the edge which resembles the edge of an escarpment.
In many places, trees overhang the vertical faces, and there are fallen trees on the sloping areas below. On the top, there is very little visible depth of soil and tree roots can be seen where there have been tree/rock falls.
The sloping area was wooded mostly with small trees near the base of the vertical faces. There
were steep sided ridges, which extended westward and down into the bottom of the steep sided ravine/valleys (Figure 3.4). In the valleys between the ridges, there were tall trees. Scattered across the area also were Santa Rosa
Station
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Figure 3.3 Highlighting the edge of the ‘mesa’ and the heavily wooded area below, looking towards Rincón de la Vieja (Author’s own photograph).
boulders (1.5 - 2.0m horizontal and 1.5m vertical). These were mostly dark brown and heavily covered with green algae, moss and fern growths and other small plants. When the boulders were hit with a small geology hammer they sounded dull and wooden, like hitting wet material and material broke away easily with the hand, exposing fine fibrous roots.
Figure 3.4 A sketch diagram showing the general topography of the area encompassing the sample sites The vertical areas had some shelves and overhangs with many deep vertical and horizontal fissures.
There were distinct colour changes associated with these deep fissures. The colour of the face varied between bright light grey, pale cream, dark red and green, almost black and areas with significant surface algal growth.
The sloping area was very steep, the soil material loose and crumbly, making climbing difficult. When wet the surface was extremely slippery. The geophagy sites were on the steep vertical faces, adjacent to the top of the mesa, below H-K trails (Figures 3.5-3.6). GPS and elevation data are presented in Appendix 1.4, Table 1.2. An
the mesa