2009 | 58 | 3-4 | 341-345
Dobór płciowy
Jacek Radwan
Sexual selection
The term sexual selection was introduced by Darwin to describe selection resulting from reproductive competition. His motivation was to explain evolution of extravagant traits characterizing many species, such as horns and feathers, occurring mostly in males. According to Darwin, despite costs associated with production and maintenance of such traits, their bearer's fitness can be increased by means of increased reproductive success: horns are used to combat reproductive competitors, and ornamental traits to attract the opposite sex. Researchers found ample evidence consistent with the mechanisms proposed by Darwin, including many examples of increased sexual attractiveness of highly ornamented males. The observation that sexually selected traits are often more pronounced in males than in females can be explained as a consequence of the asymmetry in gamete size. Reproductive success of females, a sex typically producing large gametes, is usually limited by the number of gametes produced, rather than by the access to mates, but reproductive success of males (typically producing an excess of small gametes) is limited by the access to females, which leads to reproductive competition. While the role of sexual ornaments in increasing male sexual attractiveness is well documented, the reasons why females show preferences for ornamented males are still debated. Leading hypotheses are discussed, including indicator mechanisms, where male ornament carries information about quality of resources or genes carried by males. Sexual selection is not limited to traits which increase mating success: in species where females mate with multiple males, spermatozoa compete for the fertilisation of eggs. This form of post-copulatory sexual selection (referred to as sperm competition) resulted in evolution of many spectacular adaptations parallel to those facilitating pre-copulatory competition. On the macroevolutionary scale, sexual selection has been shown to affect rates of speciation and extinction.
Instytut Nauk o Środowisku, Uniwersytet Jagielloński, Gronostajowa 7, 30-387 Kraków, Polska
Alatalo R. V., Lundberg A., Ratti O., 1990. Singing rate i female attraction in the pied flycatcher' an experiment. Anim. Beh. 39, 601-603.
Andersson M. B., 1994. Sexual selection. Princeton University Press, Princeton, NJ.
Berglund A., Rosenqvist G., Svensson I., 1989. Reproductive success of females limited by males in two pipefish species. Am. Nat. 133, 506-516.
Birkhead T. R., Moller A. P. (red.), 1998. Sperm competition and sexual selection. Academic Press, London.
Brockmann H. J., 2001. The evolution of alternative strategies and tactics. [W:] Advances in the Study of Behavior, 30, 1-51.
Chapman T., Arnqvist G., Bangham J., Rowe L., 2003. Sexual conflict. Trends Ecol. Evol. 18, 41-47.
FISHER R. A., 1930. The genetical theory of natural selection. Oxford University Press, Oxford.
Garcia C. M., Ramirez E., 2005. Evidence that sensory traps can evolve into honest signals. Nature 434, 501-505.
Hamilton W. D., Zuk M., 1982. Heritable true fitness and bright bird: A role for parasites? Science 218, 384-7.
Holland B., Rice W. R., 1998. Perspective: Chase-away sexual selection, Antagonistic seduction versus resistance. Evolution 52, 1-7.
Houle D., 1998. How should we explain variation in the genetic variance of traits? Genetica 103, 241-253.
Maan M. E., Hofker K. D., Van Alphen J. J. M., Seehausen O., 2006. Sensory drive in cichlid speciation. Am. Nat. 167, 947-954.
McLain D. K., Moulton M. P., Sanderson J. G., 1999. Sexual selection and extinction, The fate of plumage-dimorphic and plumage-monomorphic birds introduced onto islands. Evol. Ecol. Res. 1, 549-565.
Mead L. S., Arnold S. J., 2004. Quantitative genetic models of sexual selection. Trends Ecol. Evol. 19, 264-271.
Milinski M., 2006. The major histocompatibility complex, sexual selection, and mate choice. Ann. Rev. Ecol. Evol. Syst. 37, 159-186.
Moller A. P., Cuervo J. J. 1998. Speciation and feather ornamentation in birds. Evolution 52, 859-869.
Parker, G.A. 1970. Sperm competition and its evolutionary consequences in the insects. Biol. Rev. 45, 525-567.
Radwan J., 2008. Maintenance of genetic variation in sexual ornaments: a review of the mechanisms. Genetica 134, 113-127.
Rogers D. W., Grant C. A., Chapman T., Pomiankowski A., Fowler K., 2006. The influence of male and female eyespan on fertility in the stalk-eyed fly, Cyrtodiopsis dalmanni. Anim. Beh. 72, 1363-1369.
Tomkins J. L., Radwan J., Kotiaho J. S., Tregenza T. 2004. Genic capture and resolving the lek paradox. Trends Ecol. Evol. 19, 323-328.
Zahavi A. 1975. Mate selection - a selection for a handicap. J. Theor. Biol. 53, 205-14.