1. Context Dependent Outcome Amanda Acton Biology 4800

2. What is Context Dependent Outcome? Outcomes that occur as a result of interactions between species depend on the context in which they occur. It can be misleading to study any interactions between species without also looking at environmental differences Examples

6. Benefits of parasitic infection: a test using a ground squirrel – trypanosome system Why replicate the experiment performed in 1971 by Lincicome? What are the main objectives of the experiment?

7. The Experiment 140 Richardson’s ground squirrels captured Each tested for trypanosome infection 3 times, with 37 testing negative all times being used in the experiment as controls Half the squirrels were given diets containing pyridoxine, and the other half given diets deficient in pyridoxine Half of each of these groups were restricted to how much food they could consume daily (~85% body mass), where the rest could consume food as they pleased

9. Results Trypanosomes had higher intensity on squirrels that got the complete diet The ad libitum diet deficient in pyridoxine was the only treatment that showed significant effect on mass gain

10. Conclusions Some reasons why trypanosomes may have positive effects on the pyridoxine-deficient squirrels Predator avoidance Reproduction Survival through hibernation How this shows context dependent outcome?