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Published on: July 31, 2019
Optimal digestion theory does not predict the effect of pathogens on intestinal plasticity
Matthew D Venesky1, Shane M Hanlon, Kyle Lynch
1Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA. mvenesky@gmail.com
Biology Letters
|March 1, 2013
Summary
Tadpoles infected with the fungal pathogen Batrachochytrium dendrobatidis (Bd) surprisingly showed shorter intestines, contrary to optimal digestion theory predictions. This suggests energy is redirected from growth to fighting the infection.
Area of Science:
- Ecology
- Evolutionary Biology
- Amphibian Disease
Background:
- Optimal digestion theory predicts longer digestive tracts during food limitation.
- The fungal pathogen Batrachochytrium dendrobatidis (Bd) causes mouthpart damage, reducing food intake in tadpoles.
Purpose of the Study:
- To investigate if tadpoles adjust intestinal length in response to Batrachochytrium dendrobatidis (Bd) infection.
- To test predictions of optimal digestion theory in the context of disease-induced resource limitation.
Main Methods:
- Assessed the relationship between mouthpart damage and relative intestinal length in tadpoles.
- Compared relative intestinal length between Bd-exposed and unexposed tadpoles, controlling for damage.
Main Results:
- Increased mouthpart damage correlated positively with relative intestinal length, aligning with optimal digestion theory.
- Tadpoles exposed to Bd exhibited shorter relative intestinal lengths when mouthpart damage was accounted for, contradicting the theory.
Conclusions:
- Bd infection appears to override optimal digestion responses in tadpoles.
- Energy may be reallocated from intestinal growth to immune defense against Bd.
- Tadpole intestinal plasticity may be constrained by severe pathogen loads.
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