TEMPORAL CHANGES IN REPRODUCTION, COMPETITION, AND PREDATION AFTER ESTABLISHMENT OF INTRODUCED POPULATIONS OF THE GREATER EUROPEAN PINE SHOOT BEETLE, TOMICUS PINIPERDA (L.) (COLEOPTERA: CURCULIONIDAE, SCOLYTINAE) BY NICHOLAS JAMES RUDZIK A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Graduate Faculty of Forestry University of Toronto © 2009 Copyright by Nicholas James Rudzik Library and Archives Bibliothèque et Canada Archives Canada Published Heritage Direction du Branch Patrimoine de l’édition 395 Wellington Street 395, rue Wellington Ottawa ON K1A 0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre référence ISBN: 978-0-494-61075-6 Our file Notre référence ISBN: 978-0-494-61075-6 NOTICE: AVIS: The author has granted a non- L’auteur a accordé une licence non exclusive exclusive license allowing Library and permettant à la Bibliothèque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par télécommunication ou par l’Internet, prêter, telecommunication or on the Internet, distribuer et vendre des thèses partout dans le loan, distribute and sell theses monde, à des fins commerciales ou autres, sur worldwide, for commercial or non- support microforme, papier, électronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L’auteur conserve la propriété du droit d’auteur ownership and moral rights in this et des droits moraux qui protège cette thèse. Ni thesis. Neither the thesis nor la thèse ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent être imprimés ou autrement printed or otherwise reproduced reproduits sans son autorisation. without the author’s permission. In compliance with the Canadian Conformément à la loi canadienne sur la Privacy Act some supporting forms protection de la vie privée, quelques may have been removed from this formulaires secondaires ont été enlevés de thesis. cette thèse. While these forms may be included Bien que ces formulaires aient inclus dans in the document page count, their la pagination, il n’y aura aucun contenu removal does not represent any loss manquant. of content from the thesis. Temporal Changes in Reproduction, Competition and Predation After Establishment of Introduced Populations of the Greater European Pine Shoot Beetle, Tomicus piniperda (L.) (Col.: Cur., Scol.) PhD 2009, Nicholas James Rudzik, Faculty of Forestry, University of Toronto Abstract The establishment of exotic species in novel environments is a major environmental concern, however, few long-term studies have examined the effects of these species on their host environment and community, especially in forest ecosystems. The arrival and subsequent spread of the greater European pine shoot beetle, Tomicus piniperda (L.) (Coleoptera: Curculionidae, Scolytinae), into southern Ontario pine forests provided a natural experiment to assess biotic interactions between an exotic species and its new community over several years. Reproductive success of Tomicus piniperda colonies of various ages was studied between 2001 and 2004. The size and composition of competitor and natural enemy complexes present in these communities were also quantified over time. The impact of the natural enemy complexes on T. piniperda reproduction was assessed, Brood production (no. eggs and galleries/female) by T. piniperda populations rapidly approached those reported from its native range in Europe, with lower densities of parental adults. Thus, reproduction remained consistently above the replacement level for this beetle over all four years of study suggesting that these recently-introduced populations were growing rapidly and at a greater rate than in their country of origin. Tomicus piniperda successfully integrated into a large bark beetle community, and appeared to be capable of displacing native beetles to more marginal bark habitats, however, these competitors were not eliminated during the course of the study. The long-term effect of this marginalization on populations of native beetles is ii uncertain. Tomicus piniperda rapidly acquired natural enemies in the introduced areas, however, natural enemy-caused mortality did not show a regulating effect on its populations. It seems that intraspecific competition, rather than predation, regulates T. piniperda populations following introduction. The implications of these findings for the establishment and spread of exotic species in forest systems are examined, especially with reference to a prominent theory for success, the Enemy Release Hypothesis. In short, the Enemy Release Hypothesis is not applicable to an exotic species that is not regulated by natural enemies in its native range, and assessments of the Enemy Release Hypothesis should always include a determination of enemy regulation of the exotic in its native range. iii Acknowledgements There are many people who have influenced me over the course of my degree, and I wish to take this opportunity to mention them. First off, I would like to thank my supervisor, Sandy Smith, for giving me the opportunity to conduct this research and extending my student experience. My committee members (Chris Darling, Don Jackson, Jennifer Thaler in the beginning, and Peter Kotanen at the end) provided advice and helpful comments. I would also like to thank Sharon Cowling my internal examiner and Therese Poland from USFS and Michigan State, my external examiner. I am grateful to Ian Kennedy and John McCarron, for giving me invaluable field and technical support. I wish to acknowledge the owners and managers of the sites I visited in the course of my field work for their kind permission to use their land: Mr. and Mrs. Gotz, Mr. and Mrs. Hawriko, Dr. and Mrs. Chute, Gary Lammers, Bill Huff, Terry Schwann, Gord Costie, Darren Rogerson, James Lane, and Mr. and Mrs. Deller. I would like to thank my colleagues in the Smith lab for useful discussions, particularly Krista Ryall (whose M.Sc. research on the ecology of Tomicus piniperda in Ontario provided the starting point for this project), and Michelle Yakimchuk and Ryan Morgan, who worked on other aspects of Tomicus piniperda ecology. Thank you to Md. Nurul Islam for assistance with insect identification. This research was funded by a grant from the Ontario Ministry of Natural Resources, and tuition support was provided by the Faculty of Forestry and by the School of Graduate Studies, University of Toronto, for all of which I am indebted. I must also thank my roommates, the Men of 510 (especially Matthew Doyle, Dan MacQueen, and Mounir Bashour), for cheerfully putting up with me for so many years. Similarly, the members of the University of Toronto fencing team who kept me active and provided relaxation and good fellowship – chief among them Thomas Nguyen and Alex Pekurar. Lena Quinto provided encouragement and support during the final stages of the work. My sister Alanna was always ready for a cup of coffee and a chat, when things were good or bad. Finally, I would like to thank my parents, without whose love and support I could not have finished my work. I dedicate this thesis to them. My thesis is finished. DG iv TABLE OF CONTENTS Abstract ii Acknowledgements iv List of Figures ix List of Tables xii Chapter 1: Biotic Interactions of Invasive Species with Particular Reference to the Greater Pine Shoot Beetle, Tomicus piniperda Abstract 1 Invasive Exotic Species 2 Stages of Exotic Immigration 4 Effects of Invasive Species on Their Host Ecosystems 5 i. Ecosystem-Level Impacts 6 ii. Genetic Effects 6 iii. Indirect Species Effects 8 iv. Biotic Interactions 8 Evaluation of the Enemy Release Hypothesis 12 Natural Enemy Accumulation 13 Evolution of Exotic Species 15 Research on the Effects of Exotic Species 17 Biology of Tomicus piniperda in its Native Range 18 Tomicus piniperda in North America 20 Thesis Objectives and Structure 22 Chapter 2: General Methods 24 Introduction 24 Site Characteristics 24 Standard Collection Procedures 28 Trap logs for Tomicus piniperda 28 Insect collection and log metrics 32 v Data analysis 33 Multiple regression 33 Specific analyses 34 Chapter 3: Changes in Tomicus piniperda Reproduction 35 Abstract 35 Introduction 35 Materials and Methods 37 Study areas 37 Data collection 37 Data analysis 37 Statistics 37 Multiple regression models 38 Analysis of Variance and General linear models 38 Population increase 39 Software 39 Results 39 Summary statistics 39 Multiple regression models 41 ANOVA and GLM 41 Population increase 47 Discussion 55 Chapter 4: Effects of Tomicus piniperda on the Native Scolytid Community 59 Abstract 59 Introduction 59 Materials and Methods 61 Study sites 61 Data collection 61 Insect identification and species abundance 61 Data analysis 61 vi Effects of Tomicus piniperda on the abundance of native scolytids 61 Effects of Tomicus piniperda on scolytid diversity 62 Effects of native scolytids on Tomicus piniperda brood production 63 Software 63 Results 64 Scolytid species present 64 Effects of Tomicus piniperda gallery density on scolytid numbers 67 Effects of Tomicus piniperda on scolytid diversity 77 Effects of native scolytids on Tomicus piniperda brood production 78 Discussion 84 Chapter 5: Accumulation of Native Natural Enemies on an Exotic Beetle 89 Abstract 89 Introduction 89 Materials and Methods 92 Study sites 92 Data collection 92 Insect identification