1. Competition experiments

2. What is competition? What are possible response variables for a competition experiment?

3. Associate species Focal species Resource

4. Some competition questions Does associate species X affect focal species Y? How does interspecific competition (effect of X on Y) compare to intraspecific competition (effect of Y on Y)? Is competition asymmetrical? That is, does either X affect Y more than Y affect X, or vice versa? Is the strength of competition dependent on the density of the associate species (X)? Density of the focal species (Y)?

5. Additive design Focal species Associate

6. N associate N focal species Monoculture of focal

7. Substitutive design (replacement series)

8. N associate N focal species Monoculture of focal Monoculture of associate

9. N associate N focal species Monocultures of focal Monocultures of associate Response surface

10. 1.What two factors/processes are confounded in your experimental design? 2.Which type of competition question can your design answer? Which can it not?

11. Some competition questions Does associate species X affect focal species Y? How does interspecific competition (effect of X on Y) compare to intraspecific competition (effect of Y on Y)? Is competition asymmetrical? That is, does either X affect Y more than Y affect X, or vice versa? Is the strength of competition dependent on the density of the associate species (X)? Density of the focal species (Y)?

12. Some possible types of competition questions Does associate species X affect focal species Y? Additive How does interspecific competition (effect of X on Y) compare to intraspecific competition (effect of Y on Y)? Is competition asymetrical? That is, does either X affect Y more than Y affect X, or vice versa? Is the strength of competition dependent on the density of the associate species (X)? Density of the focal species (Y)?

13. Some possible types of competition questions Does associate species X affect focal species Y? Additive How does interspecific competition (effect of X on Y) compare to intraspecific competition (effect of Y on Y)? Substitutive Is competition asymetrical? That is, does either X affect Y more than Y affect X, or vice versa? Is the strength of competition dependent on the density of the associate species (X)? Density of the focal species (Y)?

14. Some possible types of competition questions Does associate species X affect focal species Y? Additive How does interspecific competition (effect of X on Y) compare to intraspecific competition (effect of Y on Y)? Substitutive Is competition asymetrical? That is, does either X affect Y more than Y affect X, or vice versa? Is the strength of competition dependent on the density of the associate species (X)? Density of the focal species (Y)? L-shaped additive or substitutive

15. Some possible types of competition questions Does associate species X affect focal species Y? Additive How does interspecific competition (effect of X on Y) compare to intraspecific competition (effect of Y on Y)? Substitutive Is competition asymetrical? That is, does either X affect Y more than Y affect X, or vice versa? Is the strength of competition dependent on the density of the associate species (X)? Density of the focal species (Y)? Additive L-shaped additive or substitutive

16. Example: Additive series design for container mosquito larvae

17. 1985 1996 Aedes albopictus invades N America from SE Asia in 1985, via used tire trade at Houston

18. Breeds in containers habitats (old tires, treeholes), like native species, Aedes aegypti Aedes albopictus

19. Ranges overlap, potential for interspecific competition

20. Experimental design (“Additive series”) Juliano, S. 1998. Species introduction and replacement amongst mosquitoes: interspecific resource competition or apparent competition? Ecology 79: 255-268. Aedes aegypti Aedes albopictus Substitutive or replacement series

21. Experimental design (Additive series) Juliano, S. 1998. Species introduction and replacement amongst mosquitoes: interspecific resource competition or apparent competition? Ecology 79: 255- 268. Aedes aegypti Aedes albopictus Addition design

22. Experimental design Juliano, S. 1998. Species introduction and replacement amongst mosquitoes: interspecific resource competition or apparent competition? Ecology 79: 255- 268. Aedes aegypti Aedes albopictus Can asses Aedes aegypti performance in these treatments

23. Hypotheses: Aedes aegypti Aedes albopictus aeg 20 20 40 60 albo 0 40 20 0 Aedes aegypti response Albo has an effect on Aeg, and effect of 1 Albo = 1Aeg aeg 20 20 40 60 albo 0 40 20 0 Aedes aegypti response Albo has no effect on Aeg, so effect of 1 Albo = 0 Aeg aeg 20 20 40 60 albo 0 40 20 0 Aedes aegypti response Albo has an effect on Aeg, but effect of 1 Albo < 1Aeg

24. Hypotheses: Aedes aegypti Aedes albopictus aeg 20 20 40 60 albo 0 40 20 0 Aedes aegypti response Albo has an effect on Aeg, and effect of 1 Albo = 1Aeg aeg 20 20 40 60 albo 0 40 20 0 Aedes aegypti response Albo has no effect on Aeg, so effect of 1 Albo = 0 Aeg aeg 20 20 40 60 albo 0 40 20 0 Aedes aegypti response Albo has an effect on Aeg, but effect of 1 Albo < 1Aeg

25. Results aeg 20 20 40 60 albo 0 40 20 0 Aedes aegypti survivorship ANOVA: treatment x food x tire(=block) Followed by t-tests (posthoc)