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A Temperature-Dependent Development Model for Willow A Temperature-Dependent Development Model for Willow Beetle Species (Coleoptera: Chrysomelidae) in Ireland: Simulation of Phenology/Voltinism in Response to Climate Change A thesis submitted for the Degree of Doctor of Philosophy October 2014 Ciarán P. Pollard Department of Geography Maynooth University National University of Ireland, Maynooth Kildare Head of Department: Dr. Jan Rigby Research Supervisors: Dr. Rowan Fealy / Dr. Christine Griffin For my parents, my family, my partner and my friends ii Word Template by Friedman & Morgan 2014 Morgan & Friedman by Word Template iii Word Template by Friedman & Morgan 2014 Morgan & Friedman by Word Template DECLARATION I, Ciarán Pollard, declare that this thesis titled, ‘A Temperature-Dependent Development Model for Willow Beetle Species (Coleoptera: Chrysomelidae): Simulation of Phenology/Voltinism in Response to Climate Change’ and the work presented in it are my own. I confirm: This work was done wholly or mainly while in the candidature for a research degree at this University. Where any part of this thesis has previously been submitted for a degree or any other qualification at this University or any other institution, this has been clearly stated. Where I have consulted the published work of others, this is always clearly attributed. Where I have quoted from the work of others, the source is always given. With the exception of such quotations, this thesis is entirely my own work. I have acknowledged all main sources of help. Where the thesis is based on work done by myself jointly with others, I have made clear exactly what was done by others and what I have contributed myself. Signed: ______________________________________________________________ Date: _________________________________________________________________ iv Word Template by Friedman & Morgan 2014 Morgan & Friedman by Word Template A Temperature-Dependent Development Model for Willow Beetle Species (Coleoptera: Chrysomelidae): Simulation of Phenology/Voltinism in Response to Climate Change Ciarán P. Pollard Abstract Rising fossil fuel prices, energy security and adherence to existing European Union (EU) climate/energy policies means that Ireland must look towards alternative energy sources to meet future demand. Woody biomass in the form of short rotation coppice willow (SRCW) is considered a viable option. SRCW is vulnerable to damage by a range of diseases and pests however. The blue (Phratora vulgatissima) and brown (Galerucella lineola) willow beetles (Coleoptera: Chrysomelidae) are identified economically as two of the most damaging insect pests of SRCW in Ireland. Policies which mandate levels of renewable energy use, to mitigate future climate change, fail to consider adaptation in the energy sector under increased levels of pestilence due to projected changes in the climate system. The effects of abiotic and biotic factors, mainly temperature and photoperiod, but also host plant, on beetle development were investigated. Constant temperature experiments showed that development time for all assessed life-cycle stages decreased as temperature increased. P. vulgatissima oviposition period and total fecundity were influenced by temperature also. Development was not found to vary considerably when P. vulgatissima larvae were reared on different host plant varieties (Tora, Resolution, Tordis and Inger) across a similar range of constant temperatures. A critical daylength (CDL) for P. vulgatissima facultative reproduction was calculated. The relationship between temperature and P. vulgatissima and G. lineola life-cycle stage development was represented by applying criteria satisfying non-linear deterministic and stochastic functions to development rates and development time distributions respectively. A combined phenology/voltinism model was constructed incorporating a Salix. viminalis degree-day budburst model, the temperature-dependent development rate and temperature-independent time distribution functions, and information regarding the reproductive diapause inducing CDL. Using observed temperature and statistically downscaled climate scenarios derived from different global climate models (GCMs) forced with different emission scenarios, model results suggested important spatio-temporal changes in the life cycle and voltinism of P. vulgatissima, including two annual generations for 5% and 50% beetle emergence proportions (E.P) at all observed locations nationally by the 2050s and three annual generations for 5% E.P for a percentage of years at certain v Word Template by Friedman & Morgan 2014 Morgan & Friedman by Word Template inland and south-westerly observed locations by the 2080s. The findings from this research may have implications for regional SRCW production, integrated pest and crop management and climate and energy policy in the future. vi Word Template by Friedman & Morgan 2014 Morgan & Friedman by Word Template ACKNOWLEDGEMENTS It seems quite usual to record acknowledgements for such works by declaring that there are so many people to thank. Fortunately for me, this is the situation. Unfortunately for all those who deserve acknowledgement, I have a terrible memory and I am bound to forget one or many, but please know that I am forever and truly grateful to all that contributed intellectually, financially and emotionally. First and foremost, I would like to express my sincerest gratitude to my two supervisors Dr. Rowan Fealy and Dr. Christine Griffin for their endless dispersion of knowledge, exceptional guidance, and sustained encouragement throughout this lengthy process. Whether it was for a rare and dreaded ‘progress update’ meeting or a more frequent and benevolent “how are you doing” chat, the ‘open door’ policy was well and truly tested. I am indebted to have had you both on my side and always pushing me towards the finish line. A wiser man once said “Surround yourself with people who make you happy. People who make you laugh, who help you when you’re in need”. I can confidently say that there was no shortage of happy and helpful individuals during my time in Maynooth. As I had the pleasure of working in both the Biology (Behavioural Ecology and Biocontrol Laboratory) and Geography (The Irish Climate Analysis and Research UnitS) departments, the list of such individuals is extensive but a special mention has to go to Catriona and Stephanie. Completing this thesis would have been a more daunting task had I not had you both to share the extreme up and down moments with. Thank you for allowing me share this experience with you. I am extremely grateful to have resided in a dynamic house in Maynooth with so many effervescent people over the years. I always looked forward to going home at the end of the day for a wind down beverage, a movie or a spirited game of Mario Kart. Another special mention has to go to a number of these full-time and part-time residents: Kevin, Lorcan and Shane for their phenomenal programming advice, proofreading and thesis formatting assistance, Pierce for looking after my beetles when I was in hospital, and Helen for nursing me back to health. Thank you for the countless laughs, greatest experiences and valued friendships. Here’s to the next wild adventure. Thank you to the official funding body, the Department of Agriculture, Food and the Marine, for supporting this project. Thank you to Stephen and Lilly for unofficially funding this research in the latter stages by employing me at Champlain College Dublin. Thank you to the staff at Teagasc, particularly Michael Gaffney, for preliminary experimentation advice vii Word Template by Friedman & Morgan 2014 Morgan & Friedman by Word Template and aiding in the provision of suitable environments for me to carry out this work. Thank you to Philip Fanning for accompanying me to the many willow sites nationwide to access and capture the offending beetle species. I would like to thank my immediate and extended family for their unconditional loyalty and love, especially my brother Seán and sister Siobhán. I would also like to thank departed but never forgotten members of my family, especially my father and my grandparents, for always encouraging me from afar. To my caring, courageous and illustrious mother, I will never be able to thank you enough, through actions or words, for everything you have provided me with in life. This work is more yours than it is mine. And finally, thank you to Jemma, for your indescribable kindness, patience and reassurance at all times. I couldn’t ask for a better friend or partner. viii Word Template by Friedman & Morgan 2014 Morgan & Friedman by Word Template CONTENTS ix Word Template by Friedman & Morgan 2014 Morgan & Friedman by Word Template 1 Introduction .................................................................................................................... 1 1.1 CLIMATE CHANGE OVERVIEW............................................................................................................. 3 1.1.1 Global Climate Observations and Projections: Temperature ......................................... 6 1.1.2 Irish Climate Observations and Projections: Temperature .......................................... 11 1.2 INSECT RESPONSES TO CLIMATE CHANGE: TEMPERATURE ....................................................... 13 1.3 SHORT ROTATION COPPICE AND LEAF-FEEDING BEETLE .......................................................... 15 1.4 GENERAL AIMS AND OBJECTIVES .................................................................................................... 20 1.5 THESIS
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