2. Biological Consequences Photos: Coalcreek.org Metal Pollution Historical Mining Metal-drainage from mines is a growing problem in the Colorado Rocky Mountains. Historical Mining Metal-drainage from mines is a growing problem in the Colorado Rocky Mountains.

3. Photos: Angus McIntosh Mayfly ( Baetis bicaudatus ) Aquatic larval stage Terrestrial Adult Larvae are algal grazers Main predators: fish and stoneflies Highly sensitive to metal toxicity (Lefcort et al. 2010)

4. Infection by Mermithid Nematode ( Gasteromermis sp. ) Jasmine Hamilton Infection alters host behavior and morphology in a variety of ways (Vance & Peckarsky 1996): Single-host obligate endoparasite! Kara Cromwell Robert Burns -Activity (drift and foraging patterns) -Larval Growth and Development -Sterility & Sex Reversal

5. Objectives of Study MetalExposure Interaction? MermithidParasitism Foraging & Drift Behavior Susceptibility to Predation Foraging & Drift Behavior Susceptibility to Predation Angus McIntosh Robert Burns

6. Study Area East River (low metals) Coal Creek (high metals) Major Mines River/Stream Standard Mine Crested Butte, CO Standard Mine Crested Butte, CO

7. Comparison of Coal Creek & East River Metals Data (Ben Koch 2005, unpublished) Raw Zn (ug/L) Raw Pb (ug/L) Raw Cd (ug/L) Raw Cu (ug/L) Detection limit

8. East River (Low Metals) Coal Creek (High Metals) Prevalence of Parasitism

9. Cattle tanks to colonize tiles with algae Individual stream channels containing 6 mayflies Series of flow-through channels Experimental Set-up

10. 2 x 2 interactive experiment Mayfly Response Variables: Foraging on exposed substrate surfaces & Drift dispersal Mayfly Response Variables: Foraging on exposed substrate surfaces & Drift dispersal

11. Behavior - foraging Parasitism increased the number of hosts grazing, especially during the day PP PP U U Low Metals High Metals No effect of metals

12. Behavior - drift Metals suppressed daytime drift Metals suppressed daytime drift Parasitism decreased drift of high-metal mayflies, especially at night, but increased it in low-metal streams Parasitism decreased drift of high-metal mayflies, especially at night, but increased it in low-metal streams PP PP U U Low MetalsHigh Metals Drift very low

13. Predation Experiment: Stonefly Predator ( Megarcys signata) Added stonefly larvae to channels Measured mayfly mortality rates Angus McIntosh

14. Susceptibility to Predation Kara Cromwell High Metals Low Metals increased Exposure to metals increased predation No parasite effect U U U U P P P P No parasite x metals interaction Drift very low

15. Summary Prevalence is not a function of metals Prevalence is not a function of metals Parasitized individuals forage more Parasitized individuals forage more Interactive effects of parasitism x metals on drift behavior Interactive effects of parasitism x metals on drift behavior High stonefly predation of Baetis from high metal streams High stonefly predation of Baetis from high metal streams

16. Implications and Future Directions Consider effects of multiple stressors on biotic interactions Consider effects of multiple stressors on biotic interactions Interactions between abiotic (metals) and biotic stressors (parasites) Interactions between abiotic (metals) and biotic stressors (parasites) What is causing variation in prevalence? ( Kara Cromwell) What is causing variation in prevalence? ( Kara Cromwell)

17. Acknowledgements 2013-2014 RMBL Benthette Team RMBL, NSF-REU Grant, Sac State, My Co-authors, Steve, Marge, Wendy, Stephanie, Alex, Maruxa, Andrea, Aaron, Jeff & Johanna, Hiromi, Brooke, Morgan, Lupe, and many more!

18. Prevalence of Parasitism July 2013 East River (Low Metals) Coal Creek (High Metals)

19. Prevalence ~17% higher in Coal Creek across both summers

20. High Metals!! Channels with stoneflies that didn’t eat omitted.

21. Stream flow I II III IV B. bicaudatus I J F M A M J J A S O N D Snow and ice cover Stage eggs Time Barbara Peckarsky