Sperm Competition

by

Simone Immler

• LAST REVIEWED: 13 January 2014
• LAST MODIFIED: 13 January 2014
• DOI: 10.1093/obo/9780199941728-0016

Introduction

Sperm competition is defined as the competition between sperm from at least two males for the fertilization of a given set of eggs. It has been established as a powerful evolutionary force driving and influencing many different aspects of evolutionary biology and behavioral ecology, including sexual selection and sexual conflict, the evolution of mating systems, speciation and reproductive isolation, and the evolution of anisogamy. It is a field of research that is still relatively young, but it has received ample attention and researchers have greatly contributed to understanding the causes and consequences of sperm competition by developing extensive theoretical work, with seminal articles summarized under Sperm Competition in Theory and a large body of empirical studies in a wide range of taxonomic groups employing a wide range of empirical tools. The sections below are chosen according to dominant subject areas within the field of sperm competition, and they address the evolution of sperm and ejaculate traits (in Sperm in Competition), economics of sperm competition (in Male Behavioral and Physiological Adaptations to Sperm Competition), the genetic background (in Sperm Competition Genetics), how to assess sperm competition (in Measuring Sperm Competition), and finally Wider Implications of Sperm Competition.

General Overviews

Since the start of this research field in the early 1970s, several valuable books have been edited and written that provide solid and comprehensive overviews of the field as it developed over the years. The earliest is the edited book Mulcahy 1975, which provides an insight into the areas of interest within the topic of gamete competition in plants and animals, following a symposium on the topic. The edited volumes Smith 1984, Birkhead and Møller 1998, and Simmons 2001 provide excellent overviews of empirical work on different aspects of sperm competition. Smith 1984 focuses on how sperm competition affects the evolution of mating systems across animal taxa, whereas Birkhead and Møller 1998 provides an accurate account of the state of the art of the field after nearly thirty years of research, and Simmons 2001 concentrates on sperm competition in insects. The most recent addition is Birkhead, et al. 2009, which summarizes the underlying biological mechanisms driving the evolution of sperm, including function, morphometry and genetics. Birkhead 2000 is an entertaining and scientifically accurate account for the general public that provides some highlights from research on sperm competition.

• Birkhead, Tim R. 2000. Promiscuity: An evolutionary history of sperm competition. Cambridge, MA: Harvard Univ. Press.

  This popular science book explains the causes and consequences of sperm competition in an easy to read and entertaining way, making it accessible to the wider public.

• Birkhead, Tim R., David J. Hosken, and Scott Pitnick, eds. 2009. Sperm biology: An evolutionary perspective. Amsterdam and London: Elsevier/Academic Press.

  This edited volume provides an excellent overview of the historical background of the study of sperm biology and the various theoretical, mechanistic, and genetic approaches employed to study the evolution of sperm.

• Birkhead, Tim R., and Anders P. Møller, eds. 1998. Sperm competition and sexual selection. London and San Diego, CA: Academic Press.

  A comprehensive edited volume summarizing the research of sperm competition from both a theoretical and an empirical point of view, with chapters reflecting the different aspects of sperm competition in various taxonomic groups.

• Mulcahy, D. L., ed. 1975. Gamete competition in plants and animals: Proceedings of the Symposium on Gamete Competition in Plants and Animals, Villa Carlotta, Lake Como, Italy, 21–23 August 1975. Amsterdam: North-Holland.

  An interesting early work providing insight into the state of the art of research and hypotheses during the early stages of research on gamete and sperm competition in particular.

• Simmons, Leigh W. 2001. Sperm competition and its evolutionary consequences in the insects. Princeton, NJ: Princeton Univ. Press.

  An accurate and extensive account of the evolutionary causes and consequences of sperm competition in the insect world.

• Smith, R. L., ed. 1984. Sperm competition and the evolution of animal mating systems. Orlando, FL: Academic Press.

  This edited volume contains contributions from leaders in the field of sperm competition discussing the implications of sperm competition for male and female mating behavior and the evolution of animal mating systems. Chapters generally are divided by specific taxa.