Lynn Drennan

Female Competition and Display in Kribensis (Pelvicachromis pulcher), a West African Cichlid

ABSTRACT

The field of sexual selection has focused on male-male competition and choice by females. This type of intrasexual competition and intersexual selection (mate choice) has been well documented experimentally. The opposite situation, female-female competition and choice by males, has only been considered fairly recently and in a few situations, typically those studying so called sex-role reversed systems. By conducting experiments on the biparental cichlid fish, Pelvicachromis pulcher, commonly called the kribensis, my objectives were to determine if a kribensis female will compete against another kribensis female for the attention of a kribensis male and to see if a kribensis male will choose his mate based on the kribensis female's display competition. More specifically, I looked at whether bright females, larger females or albino females provided longer display times when competing for a male mate. I also looked at whether a male was more likely to choose a bright, large, or an albino female versus duller or smaller females. I predicted that kribensis females do compete with displays against other kribensis females and that bright, large, and albino females will compete the most. I also predicted that kribensis males will choose their mates based on the female's display competition as well as the male choosing a bright, large or albino female. To test my objectives and predictions, research was conducted in the Evolutionary Ecology of Fishes Laboratory at California State University, Sacramento from Summer 2005 to Summer 2006. The experiment consisted of putting two females into an experimental aquarium and then introducting a male. The females were allowed to use displays to compete for a 30 minute trial. The display time of the females were recorded then they, along with the male, were left for five days so that the male could perhaps choose a female mate. As predicted, the females were found to compete against each other for the males, with the bright, larger and albino females competing the longest, and there was a general trend for the male to choose brighter and larger females. These findings provide evidence that female-female competition does occur outside of sex-revesed and uniparental mating systems and should be considered in understanding the sexual systems of a wider range of animals.

Citation

Drennan, Lynn Marie (2006) Female Competition and Display in Kribensis (Pelvicachromis pulcher), a West African Cichlid. Masters thesis, Department of Biological Sciences, California State University, Sacramento.

Lynn joined the lab in Fall of 2003 and finished in fall of 2006. .

CSUS BIO SCI