! "# $ % & % ' % ! "# !' "$% &'()!*+' ,, , , ' "# ' '% $$(' Behavioral research on wolf spiders (Araneae: Lycosidae): Assessing common assumptions and methods A dissertation for submission to the Graduate School Of the University of Cincinnati In partial fulfillment of the requirements for the degree of Doctor of Philosophy In the Department of Biological Sciences Of the McMicken College of Arts and Sciences By Jenai M. Rutledge B.S., Animal Behavior Bucknell University, Lewisburg, PA, May 2003 Committee Chair: Dr. George W. Uetz ABSTRACT. Ecological, behavioral, and evolutionary theory and research is based on a network of assumptions that simplify the otherwise complex physical and natural systems of life. Assumptions are a necessary part of conducting research because they provide a framework from which predictions about these systems can be made and tested through the interpretation of statistical analyses. However, the validity of conclusions drawn from any empirical study is only as good as the assumptions upon which the research design and interpretations were made. The research presented here addresses and tests a number of specific assumptions commonly made in research studies conducted on invertebrate animals, as applied to Schizocosa wolf spiders, an emerging animal model in animal behavior. My research focuses on two species, S. ocreata and S. rovneri well-known in studies of communication and mate choice. In two studies, I examined the traditional assumption that in invertebrates, flexibility of female mate choice behavior is minimal. From the first study it is clear that behavioral plasticity of these invertebrate animals in response to experience is greater than previous recognized. Exposure of female S. rovneri as juveniles to altered male phenotypes resulted in avoidance of familiar and preference for novel phenotypes as adults. However, these studies also show that certain types of experience (chemical vs. visual cues) may affect female mate preferences more than others, and that manipulation of male phenotypes (e.g., with nail polish) can sometimes have unintended consequences. In a second study with both S, ocreata and S. rovneri, the mechanisms that underlie species-level mate recognition (e.g., female mate preference) are more rigidly defined and do not appear to be influenced by social experience. A third study examined how well traditional measurements of body condition of spiders are able to separate out differences in feeding and/or hydration histories. This study provides evidence that S. ocreata may be able to iii modulate their apparent body condition (calculated by traditional body condition measures) when faced with short-term food and/or water deprivation. Specifically, the morphological body condition of spiders deprived of food or water remained remarkably similar for up to eight days. This suggests that current measures of body condition may not provide an accurate estimate of current body condition. Reults of these studies suggest that in designing experiments, the assumptions underlying commonplace experimental methods/techniques often go unrecognized, and if assumptions are inaccurate or wrongly applied, the validity of research can be jeopardized. It is therefore important that assumptions be evaluated in the light of novel data to ensure they are logical and current. iv v ACKNOWLEDGEMENTS I would like to thank my research advisor, George Uetz for his constant encouragement, feedback, and support. Without his dedication to my success and continued confidence in my abilities as a researcher and teacher, I would have ‘thrown-in the towel’ long ago. His down-to- earth personality and sincere interest in helping his students succeed (both in and outside of the lab) has made him great adviser and a valued friend. My committee members Elke Buschbeck, Eric Maurer, Ken Petren, and Ann Rypstra for valuable discussion and feedback, time, patience and support throughout the many many reinventions of my dissertation research. Ken Petren for all of the advice, supplies and lab space during the two years I spent trying to develop microsatellite markers for the cursed, Californian, colonial web-building spider, Metepeira spinipes. My husband Matt, my sister Jessica, and my Mom, Debbe, and Dad, Charlie for hours of field and lab assistance, professional guidance, and much emotional support (here too I thank my son, Brayden who always knows how to make me smile). To Kitty Uetz, for being a person I could turn to for help, guidance, support, encouragement, good artwork, and pretty much anything else I’ve needed. Thanks to many past and present graduate students for helpful feedback, advice, good discussion, and social pursuits; especially Julianna Johns (I would have lost my mind long ago if it weren’t for your terrific sense of humor and friendship), Brian and Christine Moskalik, and Shira Gordon. To the undergraduate researchers who have helped over the years with collection of spiders and maintenance of lab animals (especially Justin Allen and Melita Skelton). Funding for this research was provided by the American Arachnological Society, the University of Cincinnati Research Council, the National Science Foundation (IBN 0239164 to G.Uetz), the Wiemen/Wendel/Benedict Student Research Fund, and the Department of Biological Sciences. vi TABLE OF CONTENTS Behavioral research on wolf spiders (Araneae: Lycosidae): Assessing common assumptions and methods............................................................................................................................................ i ABSTRACT...................................................................................................................................iii ACKNOWLEDGEMENTS........................................................................................................... vi LIST OF TABLES......................................................................................................................... ix LIST OF FIGURES. ...................................................................................................................... xi Chapter 1: Introduction and General Overview.............................................................................. 1 References....................................................................................................................................... 9 Chapter 2: Exposure to multiple sensory cues as a juvenile affects adult female mate preferences in wolf spiders............................................................................................................................... 11 Abstract......................................................................................................................................... 12 Introduction................................................................................................................................... 13 Methods......................................................................................................................................... 15 Study Species............................................................................................................................ 15 Collection and Housing............................................................................................................. 17 Experimental Methods.............................................................................................................. 17 Results........................................................................................................................................... 23 Discussion..................................................................................................................................... 26 Acknowledgements....................................................................................................................... 31 References..................................................................................................................................... 32 Chapter 3: Effects of Juvenile Experience on Adult Female Mating Preferences in Two Closely Related Sympatric Wolf Spider Species....................................................................................... 48 Abstract......................................................................................................................................... 49 Introduction................................................................................................................................... 50 Methods......................................................................................................................................... 52 Study Species............................................................................................................................ 52 General Methods....................................................................................................................... 53 Juvenile Exposure ..................................................................................................................... 54 Adult Mate Recognition Trials ................................................................................................. 55 Statistical Analyses ................................................................................................................... 56 Results..........................................................................................................................................