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Evolution of the niche in protozoan Communities

Evolution of the niche in protozoan Communities. Tom Miller Biological Science Florida State University miller@bio.fsu.edu. William Bartram, ~1780. Outline. Who am I? What QUESTIONS am I interested in? What TECHNOLOGY do I use? Example of a project

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Evolution of the niche in protozoan Communities

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  1. Evolution of the niche in protozoan Communities Tom Miller Biological Science Florida State University miller@bio.fsu.edu William Bartram, ~1780

  2. Outline • Who am I? • What QUESTIONS am I interested in? • What TECHNOLOGY do I use? • Example of a project • Motivation: Why I use (or want to use) the individual-based approach? • Challenges: What prevents me from (or makes it difficult to) use the individual-based approach? • Opportunities: What (else) the individual-based approach could be used for?

  3. Ecology and Evolution of Species Patterns using Pitcher Plants

  4. Food web within Pitcher Plants Bacterivores Studied by: Addicot, Istock, Bradshaw, Ellison and Gotelli, Kneitel and Miller, Hoekman, many others

  5. Dominant Bacterivores Species in Sarracenia flagellates ciliates Habrotrochus Colpoda (CA) Bodo (BO) Mosquito larvae bacteriovores Sarraceniopus gibsonii bacteria Eimeriidae (BFC) dead bugs Poterioochromonas (CH)

  6. Evolution in ecological time scale What role does past or current evolution play in determining species patterns? In this system, we can quantify evolution over successional time scales because of the fast generations times.

  7. Competitive Hierarchy in Protozoa in Two Week-old Community Effect of Mosquito larvae protozoa Effect on bacteria dead bugs competitive ability rank CH < BO < BFC = CA

  8. Evolution of Interaction Strengths WEEK 2 WEEK 7 WEEK 12 less competitive effect increased competitive effect

  9. Conclusions • There is no evidence for pairwise niche convergence or divergence among competitors in this community. • Our fundamental view of species’ niche overlap driving evolution of competitors may need revision. • What is really evolving? While we measure interaction traits, we have no knowledge of the mechanisms involved. NIMBioS Question 1: At the level of individual cells, what traits or characters are actually evolving?

  10. A model of evolution with substitutable resources Resource-use matrix Per-capita interaction matrix resources species Population growth

  11. A model of evolution with substitutable resources Resource-use matrix Per-capita interaction matrix resources .1 species Population growth

  12. Resource-use matrix Per-capita interaction matrix resources .1 A model of evolution with substitutable resources species Population growth

  13. terHorst, Miller, and Power model One species diverges to specialize on Resource 1 Two species converge to specialize on Resource 1 terHorst, Miller, and Powers. 2011. Evol. Ecol. Res. 12:843-854.

  14. terHorst, Miller, and Power model • Convergence is an evolutionary outcome of competition of >2 species • Convergence or divergence can occur when there is sufficient selection and genetic variation to converge before extinction occurs. terHorst, Miller, and Powers. 2011. Evol. Ecol. Res. 12:843-854.

  15. terHorst, Miller, and Power model A problem is that the model essentially acts through group selection. It creates variation in resource use among populations, then selections the population that has the highest growth rate. This form of modeling competitors has been shown to be inaccurate. NIMBioS Question 2: What is the best way to model the simultaneous evolution of competitors, based on selection on individuals?

  16. Outline • Who am I? • What QUESTIONS am I interested in? • What TECHNOLOGY do I use? • Example of a project • Motivation: Why I use (or want to use) the individual-based approach? • Challenges: What prevents me from (or makes it difficult to) use the individual-based approach? • Opportunities: What (else) the individual-based approach could be used for?

  17. This work has been significantly supported by the National Science Foundation Thanks to the many students that either marked leaves and sucked up pitcher plants out in the miserable heat or counted protozoa in the very cold Miller lab, including Amber Roman, Casie Reed, Fani Gruber, John Mola, and Heather Wells.

  18. Evolution of Predation Tolerance WEEK 2 WEEK 7 WEEK 12 Less effect Increased effect

  19. Biogeography detail on community

  20. Community Patterns within a Field Buckley, et al. 2004

  21. Succession in Sarracenia leaves Mosquito larvae protozoa bacteria dead bugs WEEKS Low Predation High Competition High Predation Low Competition

  22. Evolution of Colpoda in competition terHorst selection experiments in the laboratory show that Colpoda evolve faster growth rates and smaller size when in competition. terHorst, 2011. J. Evol. Biol. 24:36-46

  23. Evolution of Colpoda with predation by Wyeomyia terHorst selection experiments in the laboratory show that Colpoda evolve when in predation. terHorst, Miller and Levitan, 2010. Ecology 91:629-636

  24. Poorer get rich and rich get poorer

  25. Results, again • Poorer competitors evolve to be better competitors (effect and response) • Better competitors evolve to be poorer competitors (effect and response) • All the species are converging on an intermediate competitive ability • But, NOT convergence as described before, driven by reciprocally increased competitive interactions • No evidence of a competition/predation trade-off.

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