Purdue University Purdue e-Pubs Open Access Dissertations Theses and Dissertations Spring 2015 Undercover predators: Vegetation mediates foraging, trophic cascades, and biological control by omnivorous weed seed predators Carmen K Blubaugh Purdue University Follow this and additional works at: https://docs.lib.purdue.edu/open_access_dissertations Part of the Ecology and Evolutionary Biology Commons, and the Entomology Commons Recommended Citation Blubaugh, Carmen K, "Undercover predators: Vegetation mediates foraging, trophic cascades, and biological control by omnivorous weed seed predators" (2015). Open Access Dissertations. 425. https://docs.lib.purdue.edu/open_access_dissertations/425 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. Graduate School Form 30 Updated 1/15/2015 PURDUE UNIVERSITY GRADUATE SCHOOL Thesis/Dissertation Acceptance This is to certify that the thesis/dissertation prepared By Carmen K. Blubaugh Entitled Undercover Predators: Vegetation Mediates Foraging, Trophic Cascades, and Biological Control by Omnivoroius Weed Seed Predators For the degree of Doctor of Philosophy Is approved by the final examining committee: Ian Kaplan Chair Clifford Sadof Douglas Richmond Kevin Gibson To the best of my knowledge and as understood by the student in the Thesis/Dissertation Agreement, Publication Delay, and Certification Disclaimer (Graduate School Form 32), this thesis/dissertation adheres to the provisions of Purdue University’s “Policy of Integrity in Research” and the use of copyright material. Approved by Major Professor(s): Ian Kaplan Steve Yaninek 4/29/2015 Approved by: Head of the Departmental Graduate Program Date UNDERCOVER PREDATORS: VEGETATION MEDIATES FORAGING, TROPHIC CASCADES, AND BIOLOGICAL CONTROL BY OMNIVOROUS WEED SEED PREDATORS A Dissertation Submitted to the Faculty of Purdue University by Carmen K. Blubaugh In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy May 2015 Purdue University West Lafayette, Indiana ii To Philip Keeney, Rosie Kaplan and Grandma Midge iii ACKNOWLEDGEMENTS I am infinitely grateful to my advisor, Ian Kaplan, for adeptly guiding and supporting my development as a scholar. In addition to helping me cultivate a creative research program, his example helped me demonstrate the tenacity, resourcefulness, and resilience that are prerequisites for success in academia. Thanks to my committee, Kevin Gibson, Doug Richmond, and Cliff Sadof, for bringing me to earth when I attempted unmanageable feats, and also for embracing some of my crazier ideas. Thanks to the Kaplan labmates for being the best friends, rough draft editors, emergency field assistants, and baked-good producers. Thanks to many technicians (Michelle Lee, Gareth Powell, Curt Hardin, Ivy Widick, and Christie Shee) for assistance with often-ridiculous, excruciating tasks. Thanks to my collaborators, James Hagler and Scott Machtley, for patience and guidance during my first molecular lab experience. Thanks to Rob Swihart and Patrick Zollner for helping me integrate small mammal ecology in my work. To several scholars outside Purdue (Adam Davis, Brent Danielson, Jon Lundgren, and John Orrock) who graciously answered my random emails and phone calls, providing priceless advice. And to Ken Kellner for being a patient statistics teacher, error message trouble- shooter, and steadfast friend. Finally, thanks to my parents for financial assistance, field assistance, and assistance with survival during my tenure as a graduate student. iv TABLE OF CONTENTS Page LIST OF TABLES ............................................................................................................ vii LIST OF FIGURES ......................................................................................................... viii ABSTRACT ........................................................................................................................ x CHAPTER 1. A META-ANALYSIS OF SEASONAL DYNAMICS AND SPECIES- SPECIFIC IMPACTS OF WEED SEED BIOLOGICAL CONTROL BY VERTEBRATE AND INVERTEBRATE SEED PREDATORS ...................................... 1 1.1 ABSTRACT .............................................................................................................. 1 1.2 INTRODUCTION ...................................................................................................... 2 1.2.1 Seed predator taxa: .......................................................................................... 3 1.2.2 Environmental resources: ................................................................................... 4 1.3 METHODS ................................................................................................................ 5 1.3.1 Literature search .............................................................................................. 5 1.3.2 Data collection ................................................................................................. 6 1.3.3 Statistical analysis ............................................................................................ 7 1.4 RESULTS AND DISCUSSION ............................................................................... 8 1.4.1 Seasonal variation: ........................................................................................... 8 1.4.2 Crop environment: ......................................................................................... 10 1.4.3 Seed preference: ............................................................................................. 11 1.4.4 Conclusions and synthesis: ............................................................................ 12 1.5 REFERENCES ........................................................................................................ 14 CHAPTER 2. TILLAGE COMPROMISES WEED SEED PREDATOR ACTIVITY ACROSS DEVELOPMENTAL STAGES ....................................................................... 28 2.1 ABSTRACT ............................................................................................................ 28 v Page 2.2 INTRODUCTION ................................................................................................... 29 2.3 METHODS .............................................................................................................. 31 2.2.1 Experiment 1 .................................................................................................. 31 2.2.2 Experiment 2 .................................................................................................. 33 2.2.3 Statistical Analyses ........................................................................................ 35 2.3 RESULTS ................................................................................................................ 37 2.3.1 Larval activity phenology .............................................................................. 37 2.3.2 Experiment 1 .................................................................................................. 37 2.3.3 Experiment 2 .................................................................................................. 38 2.4 DISCUSSION ......................................................................................................... 38 2.5 REFERENCES ........................................................................................................ 43 CHAPTER 3. COVER CROPS PROMOTE AGGREGATION OF OMNIVOROUS PREDATORS IN SEED PATCHES AND FACILITATE BIOLOGICAL CONTROL . 56 3.1 ABSTRACT ............................................................................................................ 56 3.2 INTRODUCTION ................................................................................................... 57 3.3 METHODS .............................................................................................................. 60 3.3.1 Study system .................................................................................................. 60 3.3.2 Field sampling ............................................................................................... 61 3.3.3 Gut content analysis ....................................................................................... 62 3.3.4 Protein mark retention trial ............................................................................ 63 3.3.5 Statistical analysis .......................................................................................... 63 3.4 RESULTS ................................................................................................................ 64 3.4.1 Pitfall sampling .............................................................................................. 64 3.4.2 Gut content analysis ....................................................................................... 65 3.5 DISCUSSION ......................................................................................................... 66 3.6 REFERENCES ........................................................................................................ 69 CHAPTER 4. DOES FEAR BEGET FEAR? MOONLIGHT AND HABITAT COMPLEXITY MEDIATE INTRAGUILD PREDATION AND NONCONSUMPTIVE EFFECTS OVER FOUR TROPHIC LEVELS ................................................................ 84 vi Page 4.1 ABSTRACT ...........................................................................................................