Courtship Behavior and Paternity Outcomes in the Sailfin Molly (Poecilia latipinna)

Hannah Littlefield ’22

Student: Hannah Littlefield ’22
Research Mentor: Tami Panhuis (OWU Department of Biological Sciences)

Poeciliopsis fish have different strategies for providing nutrients to developing embryos. The strategies range from producing yolk to sustain the embryo prior to fertilization to providing constant nutrients throughout development using specialized placenta structures. We compared ovaries of closely related Poeciliopsis species to learn about how and why these differences evolved.

Fish in the genus Poeciliopsis give live birth and vary in their degree of placentation depending on the amount of post-fertilization maternal nutrient provisioning to the developing embryos. In matrotrophic species, little yolk is produced prior to fertilization and thus placental structures that allow the mother to transfer nutrients to the embryos have evolved. Histology slides of gestated ovaries of 4 closely related Poeciliopsis species were analyzed and compared to identify morphological differences to learn about how specializations in the placenta structures evolved. To accomplish this, oocytes and embryos at varying stages, as well as follicle and embryo sac structures were photographed from the slides and compared between species to reveal how the morphological traits vary.