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Megaherbivore browsers vs. tannins: is being big enough?
Melissa H Schmitt1,2,3, Adrian M Shrader4,5, David Ward4,6
1School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa. Melissa.h.schmitt@gmail.com.
Oecologia
|October 21, 2020
Summary
Megaherbivores, like elephants, don't produce proline-rich proteins but possess other salivary proteins that bind tannins. This adaptation helps them cope with tannin-rich diets despite their large size.
Area of Science:
- Zoology
- Biochemistry
- Ecology
Background:
- Megaherbivores face physiological and ecological challenges due to their extreme body size.
- How browsing megaherbivores cope with plant secondary metabolites (PSMs), such as tannins, remains underexplored.
Purpose of the Study:
- To determine if megaherbivore browsers produce salivary tannin-binding proteins.
- To investigate mechanisms for coping with tannin-rich diets in large herbivores.
Main Methods:
- Laboratory assays were used to analyze saliva from elephants, black rhinoceros, and giraffes.
- SDS-PAGE and inhibition assays were employed to detect proline-rich proteins and tannin-binding affinity.
Main Results:
- Proline-rich proteins were not detected in the saliva of the studied megaherbivores.
- Saliva from these megaherbivores exhibited high tannin-binding affinity due to other proteins.
Conclusions:
- Browsing megaherbivores likely evolved tannin-binding proteins to mitigate negative effects of tannins.
- This adaptation complements their large body size in managing low-quality food sources.
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