Development, Stability, and Consequences of Personality in the Juvenile Red Squirrel By Amanda D. Kelley A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science In Ecology Department of Biological Sciences University of Alberta ©Amanda Kelley, 2014 1 ABSTRACT Animal personality – defined as consistent differences in behaviour among individuals – is a growing field in behavioural ecology due to its demonstrated effects on fitness. However, the ontogeny of personality under natural conditions remains relatively unexplored. In this thesis, I examine the development, stability, and consequences of juvenile personality in the North American red squirrel (Tamiasciurus hudsonicus). I demonstrate that 1) conditions in early life – particularly sibling relations – influence juvenile personality, 2) both aggression and activity change from juvenile to yearling stages, but activity maintains rank stability, 3) juveniles that gain territories early in the season do not experience a decrease in syndrome deviation, and 4) both dispersal activity and territory acquisition are influenced by juvenile aggression. These results suggest that environmental effects are important in shaping juvenile personality, and personality in turn influences a juvenile’s ability to meet the challenges associated with natal dispersal. ii PREFACE Some of the research conducted for this thesis forms part of a research collaboration (The Kluane Red Squirrel Project), led by Stan Boutin at the University of Alberta, Andrew McAdam at the University of Guelph, and Murray Humphries at McGill University. Data from 2005 used in Chapter 4 were collected by Mark Andruskiuw and Adi Boon as part of their individual research projects. All analyses, literature review, and writing in all chapters are my original work. The research project, of which this thesis is a part, received research ethics approval from the Animal Care and Use Committee: BIOSCIENCES for the University of Alberta, in accordance with the Canadian Council on Animal Care Guidelines and Policies (“effects of resource variation on behavioural and life history characteristics of red squirrels”, 679/03/13). iii ACKNOWLEDGEMENTS I would like to thank Stan Boutin for advising me throughout my graduate studies and giving me free reign with my project. I also thank Ainsley Sykes for all of the behind-the-scenes work she does. I thank Mark Andruskiw for allowing me to use some of his data, as well as for giving me excellent trapping tips. Thanks to all of the Kluane Red Squirrel Project grad students, technicians, and post-docs, especially Cory Williams, Jeff Lane, Katie MacIntosh, Kayla Deasley, Ryan Taylor, Kristin Van Katwyk, and Jess Haines. Thanks to Pete Hurd, Colleen St. Clair, and Cindy Paszkowski for serving on my supervisory and examining committees. And thanks to Karl Larsen, who introduced me to the wonderful world of squirrels and encouraged me to pursue this project. iv CONTENTS LIST OF TABLES ............................................................................................................................................ vii LIST OF FIGURES ........................................................................................................................................... ix CHAPTER 1: GENERAL INTRODUCTION ......................................................................................................... 1 The North American red squirrel (Tamiasciurus hudsonicus) .............................................................. 2 Thesis overview ..................................................................................................................................... 3 LITERATURE CITED .................................................................................................................................... 4 CHAPTER 2: THE EFFECTS OF EARLY LIFE ON JUVENILE PERSONALITY ......................................................... 6 INTRODUCTION ......................................................................................................................................... 6 METHODS .................................................................................................................................................. 8 Study population ................................................................................................................................... 8 Finding and marking litters ................................................................................................................... 8 Juvenile trapping ................................................................................................................................... 8 Open field (OF) and Mirror Image Stimulation (MIS) trials .................................................................. 8 Synthesis of aggression and activity variables ...................................................................................... 9 Shared environment ........................................................................................................................... 10 Motor development and growth ........................................................................................................ 10 Anogenital Distance ............................................................................................................................ 11 RESULTS .................................................................................................................................................. 11 Principal Component Analysis............................................................................................................. 11 Strictly shared effects ......................................................................................................................... 12 Motor development and growth ........................................................................................................ 12 Anogenital distance ............................................................................................................................ 12 DISCUSSION ............................................................................................................................................. 12 Shared environment effects ............................................................................................................... 12 Shared and individual environment effects ........................................................................................ 14 Conclusion ........................................................................................................................................... 16 LITERATURE CITED .................................................................................................................................. 25 CHAPTER 3: STABILITY ACROSS ONTOGENY ............................................................................................... 30 INTRODUCTION ....................................................................................................................................... 30 METHODS ................................................................................................................................................ 31 Testing for stability ............................................................................................................................. 31 RESULTS .................................................................................................................................................. 32 v Individual, mean-level, and differential stability ................................................................................ 32 Structural stability and ownership interaction ................................................................................... 33 DISCUSSION ............................................................................................................................................. 33 LITERATURE CITED .................................................................................................................................. 40 CHAPTER 4: CONSEQUENCES OF JUVENILE PERSONALITY ......................................................................... 43 INTRODUCTION ....................................................................................................................................... 43 METHODS ................................................................................................................................................ 44 Dispersal forays ................................................................................................................................... 44 Overwinter Survival and Territory Ownership .................................................................................... 45 Trappability ......................................................................................................................................... 45 RESULTS .................................................................................................................................................. 45 Dispersal forays ................................................................................................................................... 45 Overwinter survival and territory ownership ..................................................................................... 46 Trappability ........................................................................................................................................