Biology Dept Hamline University Male Pelvic Fin Asymmetry and Female Mate Choice in Colisa lalia by Emory Matts Sexual selection has been widely studied and consists of two components, competition and mate choice. Females may choose males with traits that are better adapted to the environment, signifying good genes.
Slight asymmetry can occur because of stress during development, such as illness or starvation.
Females choosing symmetric males could be getting mates with genes better matched to the environment. Asymmetry and mate choice in fish has not been widely studied. The dwarf gourami, Colisa lalia, was observed in two different experiments in which individual females were allowed to choose between a naturally symmetrical male and a male with one experimentally shortened pelvic fin. Female choice was evaluated in two experiments. One experiment allowed all the fish to freely interact while the other experiment kept the males in containers so they could not interact.