Impact of Male:Female Ratio on Male Mating Behaviors ofPoecilia latipinna

Schimmel/Conrades Science Center 151

Studies on intersexual mating competition show that an increase in the proportion of males leads to increased male-male aggression and decreased courtship. Mating behaviors of the U.S. sailfin molly (Poecilia latipinna) have been studied in depth, however primarily in a 1:1 male:female ratio. We hypothesized that in a more female-biased ratio males would exhibit a higher frequency of female-oriented mating and courtship behaviors and in more male-biased ratios males would demonstrate a decrease in courtship behaviors and mating frequency and an increase in male competition. We observed male P. latipinna in four differing male:female ratios of 1:1, 1:5, 2:4, and 3:3. This study demonstrated that in a social environment with an increased proportion of competitors male P. latipinna put less time and energy into courtship displays and nibbling behaviors directed at females, and more time and energy into competing with other males, but that thrusting, a behavior that potentially can pass sperm to the female, did not change.