Periodical dust loads on foods place dietary and physiological stress on the digestive system of chimpanzees, according to international researchers led by the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, as extrinsic abrasive particles carried by dust-laden winds affect tooth wear and evolutionary fitness.
The researchers collected feces from chimpanzees living at Taï National Park in the Ivory Coast and analyzed chewing efficiency during dry and rainy periods. They found that increased dust loads during dry periods result in decreased chewing efficiency. Also, they tested how dust affects tooth wear (surface texture) among the chimpanzees.
The consumption of dust-covered foods created micrometer-scale surface texture features such as fine furrows and dales on cheek teeth. Also, chewing was less intensive, resulting in fewer chews per food ingested and subsequently in larger mean fecal particle sizes.
Additionally, abrasive loads from regionally (the West African subcontinent) acting periodical dust winds were found to represent an ecological constraint on a local environment. The chimpanzees from the Taï forest are therefore one of the rarely described examples in African terrestrial environments where dust loads can be quantified and directly related to tooth wear.
The researchers further explored the relationship between tooth wear and dietary composition using the long-term observation database on chimpanzee behavior of the Tai chimpanzee project and compiled observation data for feeding durations from 1993 to 2009.
Adult chimpanzees fed on 48 different plants and seven animal sources, mostly on fruits and seeds, nuts, and leaves, with some insects, plant pith, and mammals. During the dry period, chimpanzees increase feeding time on seeds and nuts but reduce feeding on insects. Compared to males, females spent more time feeding on fruits, seeds, leaves, insects, and pith and less on nuts, seeds, and mammals.
“Understanding intraspecific feeding ecology and tooth wear patterns in chimpanzees is also a crucial first step for reconstructing the paleoecology of extinct hominins,” said Ellen Schulz-Kornas, PhD, who led the study at the former Max Planck Weizmann Center for Integrative Archaeology and Anthropology at the Max Planck Institute for Evolutionary Anthropology.
“When considering the findings of the present study, it is conceivable that dust may have also triggered a decreased chewing efficiency, leading to dietary-physiological stress on the digestive system of fossil species,” said Schulz-Kornas.
“This may be especially important in seasonally fluctuating environments with an increased bias towards dry climate phases like, for example, in the South African early hominin record between 3.2 and 1.3 million years ago,” said Schulz-Kornas.
The study, “Dust Affects Chewing Efficiency and Tooth Wear in Forest Dwelling Western Chimpanzees (Pan Troglodytes Verus),” was published by the American Journal of Physical Anthropology.
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