Mating Systems and Sexual Selection in Ungulates

............................................................................................19 INTRODUCTION ...................................................................................................... 21 I. GENERAL INTRODUCTION: CONTEXT OF THE STUDY .......................................................... 23 II. MATING SYSTEMS AND SEXUAL SELECTION: WHAT THE THEORY TELLS US .............. 27 II.1. DIVERSITY AND EVOLUTION OF MATING SYSTEMS ........................................................... 27 II.1.1. Parental care and party size ...................................................................................................... 27 II.1.2. Strategy of monopolization of mates and evolution of male mating systems........................... 28 II.2. THE THEORY OF SEXUAL SELECTION ..................................................................................... 32 II.2.1. Origin of the competition over mates ....................................................................................... 32 II.2.2. Darwin’s theory of sexual selection ......................................................................................... 32 II.2.3. The various forms of intra-sexual selection.............................................................................. 34 II.2.4. Inter-sexual selection and evolution of female mate choice..................................................... 34 II.3. VARIATION IN SEXUAL SELECTION AMONG SPECIES: THE THEORETICAL POINT OF VIEW..........................................................................................................................37 II.3.1. How to measure sexual selection?............................................................................................ 37 II.3.2. Variation in the opportunity for sexual selection...................................................................... 39 II.3.3. Variation in sexually selected traits and mechanisms of competition over mates .................... 40 III. MATING SYSTEMS AND SEXUAL SELECTION: NEW INSIGHTS FROM EMPIRICAL STUDIES .............................................................................................................................................................. 43 III.1. THE IMPORTANCE OF MAMMALS, AND ESPECIALLY UNGULATES, AS A STUDY MODEL.......................................................................................................................43 III.2. A NEW POWERFUL APPROACH BASED ON MOLECULAR TECHNIQUES.......................... 46 III.3. PARTY SIZE, SEXUAL DIMORPHISM AND THE OPPORTUNITY FOR SEXUAL SELECTION: A COMPLEX LINK................................................................................................................. 47 III.4. MATING SYSTEMS, SEXUALLY SELECTED TRAITS AND MECHANISMS OF COMPETITION OVER MATES: THE CASE OF THE UNGULATES........................................................ 49 III.4.1. Body size and mass .................................................................................................................. 50 III.4.2. Antler and horn size ................................................................................................................. 51 III.4.3. Antler and horn asymmetry ...................................................................................................... 53 III.4.4. Territory size, location, and habitat quality .............................................................................. 55 III.4.5. Chemical signals....................................................................................................................... 56 III.4.6. Acoustic signals........................................................................................................................ 57 III.4.7. Visual signals ........................................................................................................................... 58 te l-0 02 59 49 5, v er si on 1 28 F eb 2 00 8