The Evolution of Diet and Its Consequences for Lifespan
This project will examine if herbivorous and carnivorous animals differ in the consequences of diet for lifespan, especially protein content.
Recent work by Prof. Stephen Simpson and colleagues has shown that some herbivorous and omnivorous animals have reduced lifespans when fed high protein diets compared to high carbohydrate diets with similar caloric content. We would like to expand on these findings by addressing one of the next major questions: If protein content of an animal's diet affects lifespan, then are there differences in lifespan or the effects of diet on lifespan between herbivores and carnivores, whose typical diet differs significantly in protein?
There are opposing predictions for the effects of diet on longevity of herbivores and carnivores. One might predict shorter lifespans of carnivores compared to herbivores, given the negative effect of protein on lifespan and the higher protein content in the diet of carnivores. However, carnivores have had a long evolutionary history to adapt to their diets. Hence, an alternate prediction is that there is no difference in the longevity of herbivores and carnivores, possibly because carnivores have evolved adaptations to ameliorate the negative consequences of protein on lifespan. If so, it would be exciting to examine the nature of these potential adaptations. We recently completed an analysis of a database of the lifespans of hundreds of herbivorous, omnivorous and carnivorous mammals and our results support the latter hypothesis. There was no difference in the longevity of herbivorous and carnivorous mammals but, interestingly, omnivorous mammals had significantly greater longevity. However, our study of mammals was correlative and an experimental study, using arthropods as models, would provide a much better test of our hypothesis.
This proposed study would involved conducting laboratory experiments to examine how diet macronutrient content (i.e., amounts of protein, lipid and/or carbohydrates) affects the lifespan of several invertebrate carnivores. Model organisms could include carnivorous flies, lacewings, spiders, or other arthropods. The results of these studies with carnivores would then be compared to several completed studies of herbivores to examine if the response landscape differs among trophic levels. The direction that this project takes after the initial studies is fairly flexible and could include studies of: omnivorous arthropods, physiological mechanisms through which herbivores or carnivores process protein, mechanisms through which protein affects lifespan, evolutionary studies of diet diversification, etc.
If you have an interest in this project or related ideas, please feel free to contact me. For further information about me, see my profile page or my personal website (https://sites.google.com/site/shawnmwilder/).
The scope of this project can be adapted for honours or Ph.D. projects. Students applying for a Ph.D. project should have completed or be in the process of completing honours or a research-based Masters of Science. Students who have published or are in the process of publishing peer-reviewed articles are more competitive for Postgraduate Scholarships.
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The opportunity ID for this research opportunity is: 1479
Other opportunities with Dr Shawn Wilder