Life History Responses to Variation in Bacterial Food Sources in the Nematode Caenorhabditis elegans

Presenter(s): Alexander Smith

Faculty Mentor(s): Patrick Phillips & Stephen Banse

Poster 73

Session: Sciences

Diet is directly tied to the life history traits of an organism. Life history traits, such as development, reproductive capability, and lifespan, respond to changes in diet. The nematode Caenorhabditis elegans can serve as a model to demonstrate the effect of various bacterial diets on development and fecundity. Using various available natural bacteria isolates, we screened for bacterial diets that produce observable effects on the health and development of nematodes. Two bacteria species, Comamonas aquatica and Comamonas testosteroni, were observed to produce accelerated development in the growing nematodes relative to the standard laboratory diet of E. coli OP50. This prompted investigation into whether a tradeoff exists between life history traits, or whether this food source is simply a better food. We measured the number of offspring produced by organisms given a diet of Comamonas aquatica or Comamonas testosteroni and found that it is less with the number normally observed in nematodes given a diet of E. coli OP50. This demonstrates a tradeoff that is also well understood in temperature. When temperature is increase, nematode development is accelerated, and total offspring count is reduced. We found that when fed a diet of Comamonas aquatica or Comamonas testosteroni that the pattern of change relative to temperature is not consistent with nematodes on a diet of E. coli OP50. This work shows that this change in diet produces a tradeoff between development time and total offspring count, and that interactions with abiotic factors do not alleviate the tradeoff completely. Future research could show the specific nutrient composition differences in bacteria species that are responsible for the accelerated development and reduced offspring count.

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