THE IMPACTS OF A STEM BORING WEEVIL, MECINUS JANTHINUS , ON DALMATIAN TOADFLAX, LINARIA DALMATICA by Marjolein Schat A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Ecology and Environmental Sciences MONTANA STATE UNIVERSITY Bozeman, Montana December 2008 ©COPYRIGHT by Marjolein Schat 2008 All Rights Reserved ii APPROVAL of a dissertation submitted by Marjolein Schat This dissertation has been read by each member of the dissertation committee and has been found to be satisfactory regarding content, English usage, format, citation, bibliographic style, and consistency, and is ready for submission to the Division of Graduate Education. Robert K.D. Peterson Fabian Menalled Approved for the Department of Land Resources and Environmental Sciences Bruce D. Maxwell Approved for the Division of Graduate Education Dr. Carl A. Fox iii STATEMENT OF PERMISSION TO USE In presenting this dissertation in partial fulfillment of the requirements for a doctoral degree at Montana State University, I agree that the Library shall make it available to borrowers under rules of the Library. I further agree that copying of this dissertation is allowable only for scholarly purposes, consistent with “fair use” as prescribed in the U.S. Copyright Law. Requests for extensive copying or reproduction of this dissertation should be referred to ProQuest Information and Learning, 300 North Zeeb Road, Ann Arbor, Michigan 48106, to whom I have granted “the exclusive right to reproduce and distribute my dissertation in and from microform along with the non- exclusive right to reproduce and distribute my abstract in any format in whole or in part.” Marjolein Schat December 2008 iv ACKNOWLEDGEMENTS I would never have embarked on this journey without the example and encouragement provided by my father, K.A. Schat. Nor would I have been able to complete the process without the many forms of support he and my step-mother, L. Stenzler, provided along the way. I owe this degree in large part to them. I have also benefitted from the strength and encouragement of many other people far too numerous to list. In particular I would like to thank D.G.P. for talking me through the rough parts of getting started and surviving my comps, B.C. for helping me “get out of my head” by providing much needed moments of respite during the latter half my program, and R.M. and R.H. for being there to talk to on those lonely evenings and weekends in the office. This project was funded by the Montana Department of Agriculture Noxious Weed Trust Fund and additional support came from the Bozeman USFS Forestry Sciences Laboratory, Montana State University, and the Montana Agricultural Experiment Station. I could not have completed this work without the help of my many field assistants and fellow CoBRA members. Finally, but by no means least importantly, I would like to thank my committee (Robert K.D. Peterson, Fabian Menalled, David Weaver, Sharlene Sing, and Jim Jacobs) for their thoughtful insights and help at all stages of my project. Every committee member contributed valuable components to this dissertation. v TABLE OF CONTENTS 1. INTRODUCTION ..........................................................................................................1 Invasion Theory ..............................................................................................................1 Classical Biological Control ...........................................................................................7 Stages of a Classical Weed Biological Control Program ...........................................8 Choosing a Target Weed ...................................................................................... 9 Choosing Biological Control Agents .................................................................... 9 Biocontrol Agent Establishment ......................................................................... 10 Increase and Spread of Biocontrol Agents ......................................................... 11 Suppression of Target Weed .............................................................................. 11 Stability of Control and Ecosystem Restoration ................................................ 13 Concerns About Biological Control .........................................................................13 Impacts of Insects on Plants ..........................................................................................15 Photosynthesis. .........................................................................................................15 Impact of Insects on Plant Primary Physiology .......................................................18 Resource Allocation .................................................................................................21 Study Organisms ...........................................................................................................25 Linaria dalmatica .....................................................................................................25 Taxonomy ........................................................................................................... 25 Introduction and Distribution in North America ................................................ 27 Description ......................................................................................................... 28 Life Cycle ........................................................................................................... 29 Factors Limiting Growth .................................................................................... 31 Control. ............................................................................................................... 31 Fire and Linaria dalmatica . ................................................................................ 32 Mecinus janthinus ....................................................................................................33 Taxonomy ........................................................................................................... 33 European Distribution ........................................................................................ 34 Life History ........................................................................................................ 34 Mortality Factors ................................................................................................ 35 Mecinus janthinus as a Biocontrol Agent ........................................................... 36 Other Dalmatian Toadflax Biocontrol Agents .........................................................39 Objectives ......................................................................................................................39 2. IMPACT OF MECINUS JANTHINUS LARVAL AND ADULT INJURY ON GROWTH AND PRIMARY PHYSIOLOGY OF LINARIA DALMATICA UNDER CONTROLLED CONDITIONS ...................................................................................41 Abstract .........................................................................................................................41 Introduction ...................................................................................................................42 Study Organisms ...........................................................................................................44 Materials and Methods ..................................................................................................45 vi TABLE OF CONTENTS CONTINUED Irrigation ...................................................................................................................46 Plants ........................................................................................................................46 Treatments and Treatment Application ....................................................................48 Harvests ....................................................................................................................49 Growth and Biomass Measurements ........................................................................49 Gas Exchange and Fluorescence Measurements ......................................................50 Data Analysis ...........................................................................................................51 Results ...........................................................................................................................54 Adult Density and Injury ..........................................................................................54 Plant Growth and Biomass .......................................................................................55 Biomass Ratios .........................................................................................................56 Allometric Analyses .................................................................................................57 Gas Exchange and Chlorophyll Fluorescence ..........................................................59 Discussion .....................................................................................................................60 3. IMPACT OF MECINUS JANTHINUS INJURY ON GROWTH AND PRIMARY PHYSIOLOGY OF LINARIA DALMATICA IN THE FIELD ......................................80 Abstract .........................................................................................................................80 Introduction ...................................................................................................................81