University of Kentucky UKnowledge Theses and Dissertations--Biology Biology 2012 EMPIRICAL AND CONCEPTUAL APPROACHES TO LIFE-HISTORY TRADE-OFFS: THE SIZE AND NUMBER OF OFFSPRING IN BROODS OF A PARASITOID WASP Yoriko Saeki University of Kentucky, [email protected] Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Saeki, Yoriko, "EMPIRICAL AND CONCEPTUAL APPROACHES TO LIFE-HISTORY TRADE-OFFS: THE SIZE AND NUMBER OF OFFSPRING IN BROODS OF A PARASITOID WASP" (2012). Theses and Dissertations-- Biology. 8. https://uknowledge.uky.edu/biology_etds/8 This Doctoral Dissertation is brought to you for free and open access by the Biology at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Biology by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. 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REVIEW, APPROVAL AND ACCEPTANCE The document mentioned above has been reviewed and accepted by the student’s advisor, on behalf of the advisory committee, and by the Director of Graduate Studies (DGS), on behalf of the program; we verify that this is the final, approved version of the student’s dissertation including all changes required by the advisory committee. The undersigned agree to abide by the statements above. Yoriko Saeki, Student Dr. Philip Crowley, Major Professor Dr. Brian C. Rymond, Director of Graduate Studies EMPIRICAL AND CONCEPTUAL APPROACHES TO LIFE-HISTORY TRADE-OFFS: THE SIZE AND NUMBER OF OFFSPRING IN BROODS OF A PARASITOID WASP DISSERTATION A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the College of Arts and Sciences at the University of Kentucky By Yoriko Saeki Lexington, Kentucky Director: Dr. Philip Crowley, Professor, Department of Biology Lexington, Kentucky 2012 Copyright © Yoriko Saeki 2012 ABSTRACT OF DISSERTATION EMPIRICAL AND CONCEPTUAL APPROACHES TO LIFE-HISTORY TRADE-OFFS: THE SIZE AND NUMBER OF OFFSPRING IN BROODS OF A PARASITOID WASP Trade-offs in resource allocation underlie key life history traits of organisms. My dissertation focuses on the size-number trade-off in clonal broods of offspring using the polyembryonic wasp, Copidosoma bakeri parasitizing immature stages of the moth Agrotis ipsilon. I aim to characterize responses of wasp brood size and individual body mass by manipulating the environments in order to understand the allocation pattern in the size number trade-off. In reviewing the functional forms of trade-off relationships in relation to resource constraints, I distinguish among three main trade-off types based on graphical representations of the relationship between the trade-off variables: linear, convex (inverse), and concave. The size-number trade-off in C. bakeri shows convex relationship. Characteristics of the trade-off are sex specific: female broods have larger body mass but smaller brood size than do male broods. When food intake of the host was increased, the trade-off between wasp body mass and brood size for both sexes shifts toward both higher wasp brood size and higher body mass. When the host has better access to food late in development, the size-number trade-off curve moves up and to the right on the graph. However, the trait combinations shift along the same trade-off curve toward greater wasp body mass but smaller brood size when the host development time is shorter due to more resources in early in development. I also investigate temperature effects on the size-number trade-off. C. bakeri brood size significantly increases with high temperature early in host development. There is no shift in the allocation pattern of the size-number trade-off with temperature. Finally, I test effects of body mass on longevity, fecundity, and mating competitiveness of C. bakeri. Larger body size increases female longevity, and mated females produce more eggs than unmated females. There are no significant relationships between male body mass and longevity or mating competitiveness. Mating reduces male longevity independent of body mass. The different impact of body mass on fitness between male and female wasps suggests the observed sex-specific allocation patterns of the size-number trade-off. Implications of the experiments and possible follow-up work are discussed. Key words: clonal brood, host-parasitoid interaction, size-number trade-off, trade-off curve Yoriko Saeki May 21, 2012 EMPIRICAL AND CONCEPTUAL APPROACHES TO LIFE-HISTORY TRADE-OFFS: THE SIZE AND NUMBER OF OFFSPRING IN BROODS OF A PARASITOID WASP By Yoriko Saeki Philip H. Crowley, PhD Director of Dissertation Brian C. Rymond, PhD Director of Graduate Studies May 21, 2012 Table of Contents TABLE OF CONTENTS .................................................................................................. III LIST OF TABLES ............................................................................................................ VI LIST OF FIGURES ......................................................................................................... VII CHAPTER 1 INTRODUCTION .................................................................................. 1 Study System................................................................................................................ 3 Overview of the Chapters............................................................................................ 4 CHAPTER 2 ALLOCATION TRADE-OFFS AND LIFE HISTORIES: A GRAPHICAL APPROACH ................................................................................................ 7 OVERVIEW ....................................................................................................................... 7 DEFINITIONS AND TYPES OF TRADE-OFFS ......................................................................... 8 THE CONSTRAINING VARIABLE THAT FORCES THE TRADE-OFF ........................................ 10 THE RELATIONSHIP BETWEEN TWO LIFE-HISTORY TRAITS THAT TRADE OFF: SHAPES OF TRADE-OFF CURVES ........................................................................................................ 13 Linear relationship (Figure 2.1A) ............................................................................. 14 Linear-bent relationship (Figure 2.1B) ..................................................................... 15 Concave relationship (Figure 2.1C) ......................................................................... 16 Convex relationship (Figure 2.1D) ........................................................................... 16 COST-BENEFIT FITNESS RELATIONSHIPS ASSOCIATED WITH TRAIT MAGNITUDES AND TRADE-OFF ALLOCATION PATTERNS ................................................................................ 17 THE SHAPE OF TRADE-OFFS, ALLOCATION PATTERNS, AND ENVIRONMENTS .................... 18 SUMMARY ...................................................................................................................... 20 CHAPTER 3 A SEX-SPECIFIC SIZE-NUMBER TRADE-OFF IN CLONAL BROODS ............................................................................................................... 27 INTRODUCTION .............................................................................................................. 27 MATERIALS AND METHODS ............................................................................................ 29 Focal system.............................................................................................................. 29 Empirical methods .................................................................................................... 30 Data Analysis ............................................................................................................ 32 (i) Trade-off between the number and mass of progeny ....................................... 32 (ii) Interaction with host resources ....................................................................... 33 RESULTS......................................................................................................................... 35 Basic brood data ....................................................................................................... 35 Trade-off between the number and size of progeny .................................................. 36 Interaction with host resources ................................................................................. 37 DISCUSSION ..................................................................................................................