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Behavioral and ecological consequences of multiple intraguild predators and connections between predators, prey, and ecosystem function

Sitvarin, Michael Ian

Abstract Details

2014, Doctor of Philosophy, Miami University, Zoology.
Prey species sit at a pivotal point in food webs, serving as a connection between predators and energy sources (e.g., plants or detritus). Most prey face multiple predators and must integrate information about predation risk if they are to avoid being consumed. Meanwhile, predators interact with one another and can increase or decrease their combined pressure on prey. By interacting with their prey, predators can indirectly affect ecosystem functions, even without reducing prey population size. The goal of my dissertation was to understand how prey survive in a world with multiple predators and to uncover linkages between predators and the soil food web. I first tested hypotheses about how the wolf spider Pardosa milvina responds to cues from multiple predators (the larger wolf spider Tigrosa helluo and the ground beetle Scarites quadriceps) and how inaccurate information regarding predation threat affects survival. Pardosa were capable of distinguishing between predators and responding adaptively, though prey responses were not optimized when predators were at elevated hunger levels. As a second step, I allowed multiple predators (the wolf spider Rabidosa rabida along with Tigrosa and Scarites) to freely interact with each other and their prey (Pardosa) to test the influence of predator characteristics and the occurrence of intraguild predation on prey survival. Overall, I found support for a predictive framework of emergent multiple predator effects, though intraguild predation events caused significant deviations from model predictions. I also investigated the consumptive and nonconsumptive effects predators can have on their environment, focusing on the detrital food chain. The presence of either Pardosa or their cues impacted CO2 flux and soil nitrogen content as mediated by the detritivore Sinella curviseta, suggesting indirect top-down control of ecosystem function by predators. Finally, I tested the response of Sinella to cues indicating predation risk to determine if changes in detritivore activity linked predators to ecosystem function. Sinella responded innately to necromones but did not alter activity levels in the presence of Pardosa cues, even after a conditioning period.
Ann Rypstra, Ph.D. (Advisor)
Nancy Solomon, Ph.D. (Committee Member)
Brian Keane, Ph.D. (Committee Member)
Tom Crist, Ph.D. (Committee Member)
Dave Gorchov, Ph.D. (Committee Member)
150 p.

Recommended Citations

Citations

  • Sitvarin, M. I. (2014). Behavioral and ecological consequences of multiple intraguild predators and connections between predators, prey, and ecosystem function [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1408538928

    APA Style (7th edition)

  • Sitvarin, Michael. Behavioral and ecological consequences of multiple intraguild predators and connections between predators, prey, and ecosystem function. 2014. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1408538928.

    MLA Style (8th edition)

  • Sitvarin, Michael. "Behavioral and ecological consequences of multiple intraguild predators and connections between predators, prey, and ecosystem function." Doctoral dissertation, Miami University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1408538928

    Chicago Manual of Style (17th edition)