A comparison of light intensity preferences for an oviposition site in parthenogenetic and bisexual strains of Drosophila.

On the assumption that the survival of a parthenogenetic strain in nature relies on the strain's ability to compete with the bisexual population, we attempted to discern any diminution of competition between bisexual strains of Drosophila and parthenogenetic strains derived from them on the basis of light intensity preferences in choosing an oviposition site. Four different experiential conditions were imposed on each strain prior to testing for light intensity preferences for an oviposition site. Most light responses are significantly different in each strain for the four experiences. There are also significant differences among the bisexual, unisexual and F1 females of a given strain and between strains. Further experiments were performed to determine light preferences during oviposition when unisexual and bisexual females were in direct competition. In only one comparison were their light preferences significantly different. All strains were unique in their overall behavioral spectra.